AST: Activity-Security-Trust driven modeling of time varying networks

PubMed Central

Wang, Jian; Xu, Jiake; Liu, Yanheng; Deng, Weiwen

2016-01-01

Network modeling is a flexible mathematical structure that enables to identify statistical regularities and structural principles hidden in complex systems. The majority of recent driving forces in modeling complex networks are originated from activity, in which an activity potential of a time invariant function is introduced to identify agents’ interactions and to construct an activity-driven model. However, the new-emerging network evolutions are already deeply coupled with not only the explicit factors (e.g. activity) but also the implicit considerations (e.g. security and trust), so more intrinsic driving forces behind should be integrated into the modeling of time varying networks. The agents undoubtedly seek to build a time-dependent trade-off among activity, security, and trust in generating a new connection to another. Thus, we reasonably propose the Activity-Security-Trust (AST) driven model through synthetically considering the explicit and implicit driving forces (e.g. activity, security, and trust) underlying the decision process. AST-driven model facilitates to more accurately capture highly dynamical network behaviors and figure out the complex evolution process, allowing a profound understanding of the effects of security and trust in driving network evolution, and improving the biases induced by only involving activity representations in analyzing the dynamical processes. PMID:26888717

Time-varying delays compensation algorithm for powertrain active damping of an electrified vehicle equipped with an axle motor during regenerative braking

NASA Astrophysics Data System (ADS)

Zhang, Junzhi; Li, Yutong; Lv, Chen; Gou, Jinfang; Yuan, Ye

2017-03-01

The flexibility of the electrified powertrain system elicits a negative effect upon the cooperative control performance between regenerative and hydraulic braking and the active damping control performance. Meanwhile, the connections among sensors, controllers, and actuators are realized via network communication, i.e., controller area network (CAN), that introduces time-varying delays and deteriorates the control performances of the closed-loop control systems. As such, the goal of this paper is to develop a control algorithm to cope with all these challenges. To this end, the models of the stochastic network induced time-varying delays, based on a real in-vehicle network topology and on a flexible electrified powertrain, were firstly built. In order to further enhance the control performances of active damping and cooperative control of regenerative and hydraulic braking, the time-varying delays compensation algorithm for the electrified powertrain active damping during regenerative braking was developed based on a predictive scheme. The augmented system is constructed and the H∞ performance is analyzed. Based on this analysis, the control gains are derived by solving a nonlinear minimization problem. The simulations and hardware-in-loop (HIL) tests were carried out to validate the effectiveness of the developed algorithm. The test results show that the active damping and cooperative control performances are enhanced significantly.

Trends and drivers of fire activity vary across California aridland ecosystems

USGS Publications Warehouse

Syphard, Alexandra D.; Keeley, Jon E.; Abatzoglou, John T.

2017-01-01

Fire activity has increased in western US aridland ecosystems due to increased human-caused ignitions and the expansion of flammable exotic grasses. Because many desert plants are not adapted to fire, increased fire activity may have long-lasting ecological impacts on native vegetation and the wildlife that depend on it. Given the heterogeneity across aridland ecosystems, it is important to understand how trends and drivers of fire vary, so management can be customized accordingly. We examined historical trends and quantified the relative importance of and interactions among multiple drivers of fire patterns across five aridland ecoregions in southeastern California from 1970 to 2010. Fire frequency increased across all ecoregions for the first couple decades, and declined or plateaued since the 1990s; but area burned continued to increase in some regions. The relative importance of anthropogenic and biophysical drivers varied across ecoregions, with both direct and indirect influences on fire. Anthropogenic variables were equally important as biophysical variables, but some contributed indirectly, presumably via their influence on annual grass distribution and abundance. Grass burned disproportionately more than other cover types, suggesting that addressing exotics may be the key to fire management and conservation in much of the area.

Innovation diffusion on time-varying activity driven networks

NASA Astrophysics Data System (ADS)

Rizzo, Alessandro; Porfiri, Maurizio

2016-01-01

Since its introduction in the 1960s, the theory of innovation diffusion has contributed to the advancement of several research fields, such as marketing management and consumer behavior. The 1969 seminal paper by Bass [F.M. Bass, Manag. Sci. 15, 215 (1969)] introduced a model of product growth for consumer durables, which has been extensively used to predict innovation diffusion across a range of applications. Here, we propose a novel approach to study innovation diffusion, where interactions among individuals are mediated by the dynamics of a time-varying network. Our approach is based on the Bass' model, and overcomes key limitations of previous studies, which assumed timescale separation between the individual dynamics and the evolution of the connectivity patterns. Thus, we do not hypothesize homogeneous mixing among individuals or the existence of a fixed interaction network. We formulate our approach in the framework of activity driven networks to enable the analysis of the concurrent evolution of the interaction and individual dynamics. Numerical simulations offer a systematic analysis of the model behavior and highlight the role of individual activity on market penetration when targeted advertisement campaigns are designed, or a competition between two different products takes place.

Perianal Crohn's disease - association with significant inflammatory activity in proximal small bowel segments.

PubMed

Xavier, Sofia; Cúrdia Gonçalves, Tiago; Dias de Castro, Francisca; Magalhães, Joana; Rosa, Bruno; Moreira, Maria João; Cotter, José

2018-04-01

Perianal Crohn's disease (CD) prevalence varies according to the disease location, being particularly frequent in patients with colonic involvement. We aimed to evaluate small bowel involvement and compare small bowel capsule endoscopy findings and inflammatory activity between patients with and without perianal disease. Retrospective single-center study including 71 patients - all patients with perianal CD (17 patients) who performed a small bowel capsule endoscopy were included, and non-perianal CD patients were randomly selected (54 patients). Clinical and analytical variables at diagnosis were reviewed. Statistical analysis was performed with SPSS v21.0 and a two-tailed p value <.05 was defined as indicating statistical significance. Patients had a median age of 30 ± 16 years with 52.1% females. Perianal disease was present in 23.9%. Patients with perianal disease had significantly more relevant findings (94.1% vs 66.6%, p = .03) and erosions (70.6% vs 42.6%, p = .04), however, no differences were found between the two groups regarding ulcer, villous edema and stenosis detection. Overall, patients with perianal disease had more frequently significant small bowel inflammatory activity, defined as a Lewis Score ≥135 (94.1% vs 64.8%, p = .03), and higher Lewis scores in the first and second tertiles (450 ± 1129 vs 0 ± 169, p = .02 and 675 ± 1941 vs 0 ± 478, p = .04, respectively). No differences were found between the two groups regarding third tertile inflammatory activity assessed with the Lewis Score. Patients with perianal CD have significantly higher inflammatory activity in the small bowel, particularly in proximal small bowel segments, when compared with patients without perianal disease.

Interactions between financial stress and economic activity for the U.S.: A time- and frequency-varying analysis using wavelets

NASA Astrophysics Data System (ADS)

Ferrer, Román; Jammazi, Rania; Bolós, Vicente J.; Benítez, Rafael

2018-02-01

This paper examines the interactions between the main U.S. financial stress indices and several measures of economic activity in the time-frequency domain using a number of continuous cross-wavelet tools, including the usual wavelet squared coherence and phase difference as well as two new summary wavelet-based measures. The empirical results show that the relationship between financial stress and the U.S. real economy varies considerably over time and depending on the time horizon considered. A significant adverse effect of financial stress on U.S. economic activity is observed since the onset of the subprime mortgage crisis in the summer of 2007, indicating that the impact of financial market stress on the real economy is particularly severe during periods of major financial turmoil. Furthermore, the significant linkage between financial stress and the economic environment is mostly concentrated at time horizons from one to four years, demonstrating that the effect of financial stress on economic activity is especially visible in the long-run.

Does proprioceptive acuity during active knee rotation in the transverse plane vary at different ranges?

PubMed

Muaidi, Qassim I

2016-11-21

Knee proprioception in the sagittal plane has been widely investigated in prospective studies, however limited information is known about proprioceptive acuity during active knee rotation and the way most commonly injured. To investigate whether proprioceptive acuity during active internal and external knee rotation varies at different ranges in the transverse plane. Healthy volunteers (N: 26) without previous injury or surgery of the knee joint participated in the study.Knee rotation proprioceptive acuity was measured using a custom-designed device. The measure of proprioceptive acuity used in this study was the just-noticeable-difference (JND). Participants actively rotated the knee at different intervals(initial, mid, and terminal internal or external rotation range) to one of four movement blocks and the magnitude of the permitted motion was judged. The means of the JND for proprioceptive acuity at initial internal rotation (0.80° ± 0.06) were significantly (p< 0.002) lower than for mid (1.62° ± 0.18), and terminal (2.08° ± 0.35) internal rotation. The means of the JND for proprioceptive acuity at initial external rotation (1.16° ± 0.10) were significantly (p< 0.04) lower than for mid (1.95° ± 0.30), and terminal (1.97° ± 0.24) internal rotation. Participants perceived smaller differences between active internal and external rotation movements at initial rotation range than at the mid and terminal rotation range of movement. This suggests better proprioceptive acuity at the initial rotation range of movement in the transverse plane.

Identification of sequence motifs significantly associated with antisense activity.

PubMed

McQuisten, Kyle A; Peek, Andrew S

2007-06-07

Predicting the suppression activity of antisense oligonucleotide sequences is the main goal of the rational design of nucleic acids. To create an effective predictive model, it is important to know what properties of an oligonucleotide sequence associate significantly with antisense activity. Also, for the model to be efficient we must know what properties do not associate significantly and can be omitted from the model. This paper will discuss the results of a randomization procedure to find motifs that associate significantly with either high or low antisense suppression activity, analysis of their properties, as well as the results of support vector machine modelling using these significant motifs as features. We discovered 155 motifs that associate significantly with high antisense suppression activity and 202 motifs that associate significantly with low suppression activity. The motifs range in length from 2 to 5 bases, contain several motifs that have been previously discovered as associating highly with antisense activity, and have thermodynamic properties consistent with previous work associating thermodynamic properties of sequences with their antisense activity. Statistical analysis revealed no correlation between a motif's position within an antisense sequence and that sequences antisense activity. Also, many significant motifs existed as subwords of other significant motifs. Support vector regression experiments indicated that the feature set of significant motifs increased correlation compared to all possible motifs as well as several subsets of the significant motifs. The thermodynamic properties of the significantly associated motifs support existing data correlating the thermodynamic properties of the antisense oligonucleotide with antisense efficiency, reinforcing our hypothesis that antisense suppression is strongly associated with probe/target thermodynamics, as there are no enzymatic mediators to speed the process along like the RNA Induced

Time-varying phononic crystals

NASA Astrophysics Data System (ADS)

Wright, Derek Warren

The primary objective of this thesis was to gain a deeper understanding of acoustic wave propagation in phononic crystals, particularly those that include materials whose properties can be varied periodically in time. This research was accomplished in three ways. First, a 2D phononic crystal was designed, created, and characterized. Its properties closely matched those determined through simulation. The crystal demonstrated band gaps, dispersion, and negative refraction. It served as a means of elucidating the practicalities of phononic crystal design and construction and as a physical verification of their more interesting properties. Next, the transmission matrix method for analyzing 1D phononic crystals was extended to include the effects of time-varying material parameters. The method was then used to provide a closed-form solution for the case of periodically time-varying material parameters. Some intriguing results from the use of the extended method include dramatically altered transmission properties and parametric amplification. New insights can be gained from the governing equations and have helped to identify the conditions that lead to parametric amplification in these structures. Finally, 2D multiple scattering theory was modified to analyze scatterers with time-varying material parameters. It is shown to be highly compatible with existing multiple scattering theories. It allows the total scattered field from a 2D time-varying phononic crystal to be determined. It was shown that time-varying material parameters significantly affect the phononic crystal transmission spectrum, and this was used to switch an incident monochromatic wave. Parametric amplification can occur under certain circumstances, and this effect was investigated using the closed-form solutions provided by the new 1D method. The complexity of the extended methods grows logarithmically as opposed linearly with existing methods, resulting in superior computational complexity for large

Outcome of papillary versus clear cell renal cell carcinoma varies significantly in non-metastatic disease

PubMed Central

Edelmann, Dominic; Benner, Axel; Zigeuner, Richard; Borgmann, Hendrik; Wolff, Ingmar; Krabbe, Laura M.; Musquera, Mireia; Dell’Oglio, Paolo; Capitanio, Umberto; Klatte, Tobias; Cindolo, Luca; May, Matthias; Brookman-May, Sabine D.

2017-01-01

Renal cell carcinoma (RCC) comprises a heterogenous group of tumors. Traditionally, papillary RCC (pRCC) is associated with a favorable outcome compared to clear cell RCC (ccRCC), while other series report equivalent or worse prognosis. In this paper we comparatively evaluate outcome of pRCC versus ccRCC in two large multi-institutional databases (cohort study), including distribution of pRCC subtypes 1 and 2. Retrospective data of 1,943 surgically treated pRCC patients from 17 European/ North American centers between 1984–2015 were compared to 5,600 ccRCC patients from a database comprising 11 European/ North American centers (1984–2011). Median follow-up was 64.6 months. Differences between pRCC, subtypes, and ccRCC were compared with t-tests, Chi^2-tests, and exact Fisher tests. Cancer-specific mortality was analyzed with cumulative incidence curves and Cox cause-specific hazard models. The robustness of our results was examined with sensitivity analyses. We present that cancer-specific mortality rates and variables as stage, lymph node, and distant metastasis differ significantly between groups. Furthermore, we demonstrate that patients with non-metastatic pRCC had a significantly better cancer-specific mortality (HR 0.76, p = 0.007), when compared to ccRCC. Additionally, pRCC type 2 versus ccRCC exhibited no difference in cancer-specific mortality (HR 0.9, p = 0.722), whereas pRCC type 1 versus ccRCC displayed a risk of death reduced by 69% (p = 0.044). Taken together, outcome of pRCC versus ccRCC varies significantly in non-metastatic disease. Furthermore, pRCC type 2 exhibited no difference in cancer-specific mortality, whereas pRCC type 1 displayed a significantly reduced risk of death. Consequently, there is urgent need to respect histopathological entities and their subtypes, when assigning follow-up or targeted therapy to RCC patients. PMID:28934212

Burstiness and tie activation strategies in time-varying social networks.

PubMed

Ubaldi, Enrico; Vezzani, Alessandro; Karsai, Márton; Perra, Nicola; Burioni, Raffaella

2017-04-13

The recent developments in the field of social networks shifted the focus from static to dynamical representations, calling for new methods for their analysis and modelling. Observations in real social systems identified two main mechanisms that play a primary role in networks' evolution and influence ongoing spreading processes: the strategies individuals adopt when selecting between new or old social ties, and the bursty nature of the social activity setting the pace of these choices. We introduce a time-varying network model accounting both for ties selection and burstiness and we analytically study its phase diagram. The interplay of the two effects is non trivial and, interestingly, the effects of burstiness might be suppressed in regimes where individuals exhibit a strong preference towards previously activated ties. The results are tested against numerical simulations and compared with two empirical datasets with very good agreement. Consequently, the framework provides a principled method to classify the temporal features of real networks, and thus yields new insights to elucidate the effects of social dynamics on spreading processes.

Burstiness and tie activation strategies in time-varying social networks

NASA Astrophysics Data System (ADS)

Ubaldi, Enrico; Vezzani, Alessandro; Karsai, Márton; Perra, Nicola; Burioni, Raffaella

2017-04-01

The recent developments in the field of social networks shifted the focus from static to dynamical representations, calling for new methods for their analysis and modelling. Observations in real social systems identified two main mechanisms that play a primary role in networks’ evolution and influence ongoing spreading processes: the strategies individuals adopt when selecting between new or old social ties, and the bursty nature of the social activity setting the pace of these choices. We introduce a time-varying network model accounting both for ties selection and burstiness and we analytically study its phase diagram. The interplay of the two effects is non trivial and, interestingly, the effects of burstiness might be suppressed in regimes where individuals exhibit a strong preference towards previously activated ties. The results are tested against numerical simulations and compared with two empirical datasets with very good agreement. Consequently, the framework provides a principled method to classify the temporal features of real networks, and thus yields new insights to elucidate the effects of social dynamics on spreading processes.

Comparison of adult physical activity levels in three Swiss alpine communities with varying access to motorized transportation.

PubMed

Dombois, Oliver Thommen; Braun-Fahrländer, Charlotte; Martin-Diener, Eva

2007-09-01

To compare physical activity levels of residents of three Swiss alpine communities with varying access to motorized transport and to investigate whether socio-demographic factors, the settlement structure or means of transport affect these levels. Between January and February 2004 a computer assisted telephone interview was conducted with 901 randomly selected adults aged 18 years or older living in three Swiss alpine communities. In particular, information on moderate and vigorous intensity physical activities and on transport behaviour was collected. Respondents were categorized as 'sufficiently active' or 'insufficiently active' according to self-reported physical activity. People living in community 1 without access to motorized traffic were significantly more likely to be sufficiently active (Sex- and age-adjusted prevalences of sufficient total physical activity, 43.9% 95% CI: 38.3%-49.8%) compared to individuals living in the other two communities (community 2: 35.9%, 95% CI: 30.6%-41.6%, community 3: 32.7%, 95% CI: 27.5%-38.3%). The differences were due to higher levels of moderate physical activities. Vigorous physical activity levels did not differ between the communities. Community differences were explained by passive means of transport to work and for leisure time activities. Although the environment encountered in the three alpine communities is generally conducive to physical activity the majority of the participants did not achieve recommended activity levels. Passive mode of transport to work and during leisure time was strongly associated with insufficient total physical activity. Walking and cycling for transportation is thus a promising approach to promote health enhancing physical activity.

A Resume of Stochastic, Time-Varying, Linear System Theory with Application to Active-Sonar Signal-Processing Problems

DTIC Science & Technology

1981-06-15

relationships 5 3. Normalized energy in ambiguity function for i = 0 14 k ilI SACLANTCEN SR-50 A RESUME OF STOCHASTIC, TIME-VARYING, LINEAR SYSTEM THEORY WITH...the order in which systems are concatenated is unimportant. These results are exactly analogous to the results of time-invariant linear system theory in...REFERENCES 1. MEIER, L. A rdsum6 of deterministic time-varying linear system theory with application to active sonar signal processing problems, SACLANTCEN

Multistability of neural networks with discontinuous non-monotonic piecewise linear activation functions and time-varying delays.

PubMed

Nie, Xiaobing; Zheng, Wei Xing

2015-05-01

This paper is concerned with the problem of coexistence and dynamical behaviors of multiple equilibrium points for neural networks with discontinuous non-monotonic piecewise linear activation functions and time-varying delays. The fixed point theorem and other analytical tools are used to develop certain sufficient conditions that ensure that the n-dimensional discontinuous neural networks with time-varying delays can have at least 5(n) equilibrium points, 3(n) of which are locally stable and the others are unstable. The importance of the derived results is that it reveals that the discontinuous neural networks can have greater storage capacity than the continuous ones. Moreover, different from the existing results on multistability of neural networks with discontinuous activation functions, the 3(n) locally stable equilibrium points obtained in this paper are located in not only saturated regions, but also unsaturated regions, due to the non-monotonic structure of discontinuous activation functions. A numerical simulation study is conducted to illustrate and support the derived theoretical results. Copyright © 2015 Elsevier Ltd. All rights reserved.

Linear Parameter Varying Identification of Dynamic Joint Stiffness during Time-Varying Voluntary Contractions

PubMed Central

Golkar, Mahsa A.; Sobhani Tehrani, Ehsan; Kearney, Robert E.

2017-01-01

Dynamic joint stiffness is a dynamic, nonlinear relationship between the position of a joint and the torque acting about it, which can be used to describe the biomechanics of the joint and associated limb(s). This paper models and quantifies changes in ankle dynamic stiffness and its individual elements, intrinsic and reflex stiffness, in healthy human subjects during isometric, time-varying (TV) contractions of the ankle plantarflexor muscles. A subspace, linear parameter varying, parallel-cascade (LPV-PC) algorithm was used to identify the model from measured input position perturbations and output torque data using voluntary torque as the LPV scheduling variable (SV). Monte-Carlo simulations demonstrated that the algorithm is accurate, precise, and robust to colored measurement noise. The algorithm was then used to examine stiffness changes associated with TV isometric contractions. The SV was estimated from the Soleus EMG using a Hammerstein model of EMG-torque dynamics identified from unperturbed trials. The LPV-PC algorithm identified (i) a non-parametric LPV impulse response function (LPV IRF) for intrinsic stiffness and (ii) a LPV-Hammerstein model for reflex stiffness consisting of a LPV static nonlinearity followed by a time-invariant state-space model of reflex dynamics. The results demonstrated that: (a) intrinsic stiffness, in particular ankle elasticity, increased significantly and monotonically with activation level; (b) the gain of the reflex pathway increased from rest to around 10–20% of subject's MVC and then declined; and (c) the reflex dynamics were second order. These findings suggest that in healthy human ankle, reflex stiffness contributes most at low muscle contraction levels, whereas, intrinsic contributions monotonically increase with activation level. PMID:28579954

Does Compound I Vary Significantly between Isoforms of Cytochrome P450?

PubMed Central

2011-01-01

The cytochrome P450 (CYP) enzymes are important in many areas, including pharmaceutical development. Subtle changes in the electronic structure of the active species, Compound I, have been postulated previously to account partly for the experimentally observed differences in reactivity between isoforms. Current predictive models of CYP metabolism typically assume an identical Compound I in all isoforms. Here we present a method to calculate the electronic structure and to estimate the Fe–O bond enthalpy of Compound I, and apply it to several human and bacterial CYP isoforms. Conformational flexibility is accounted for by sampling large numbers of structures from molecular dynamics simulations, which are subsequently optimized with density functional theory (B3LYP) based quantum mechanics/molecular mechanics. The observed differences in Compound I between human isoforms are small: They are generally smaller than the spread of values obtained for the same isoform starting from different initial structures. Hence, it is unlikely that the variation in activity between human isoforms is due to differences in the electronic structure of Compound I. A larger difference in electronic structure is observed between the human isoforms and P450cam and may be explained by the slightly different hydrogen-bonding environment surrounding the cysteinyl sulfur. The presence of substrate in the active site of all isoforms studied appears to cause a slight decrease in the Fe–O bond enthalpy, apparently due to displacement of water out of the active site, suggesting that Compound I is less stable in the presence of substrate. PMID:21863858

Error-related negativity varies with the activation of gender stereotypes.

PubMed

Ma, Qingguo; Shu, Liangchao; Wang, Xiaoyi; Dai, Shenyi; Che, Hongmin

2008-09-19

The error-related negativity (ERN) was suggested to reflect the response-performance monitoring process. The purpose of this study is to investigate how the activation of gender stereotypes influences the ERN. Twenty-eight male participants were asked to complete a tool or kitchenware identification task. The prime stimulus is a picture of a male or female face and the target stimulus is either a kitchen utensil or a hand tool. The ERN amplitude on male-kitchenware trials is significantly larger than that on female-kitchenware trials, which reveals the low-level, automatic activation of gender stereotypes. The ERN that was elicited in this task has two sources--operation errors and the conflict between the gender stereotype activation and the non-prejudice beliefs. And the gender stereotype activation may be the key factor leading to this difference of ERN. In other words, the stereotype activation in this experimental paradigm may be indexed by the ERN.

Time-varying analysis of electrodermal activity during exercise

PubMed Central

Reljin, Natasa; Mills, Craig; Mills, Ian; Florian, John P.; VanHeest, Jaci L.; Chon, Ki H.

2018-01-01

The electrodermal activity (EDA) is a useful tool for assessing skin sympathetic nervous activity. Using spectral analysis of EDA data at rest, we have previously found that the spectral band which is the most sensitive to central sympathetic control is largely confined to 0.045 to 0.25 Hz. However, the frequency band associated with sympathetic control in EDA has not been studied for exercise conditions. Establishing the band limits more precisely is important to ensure the accuracy and sensitivity of the technique. As exercise intensity increases, it is intuitive that the frequencies associated with the autonomic dynamics should also increase accordingly. Hence, the aim of this study was to examine the appropriate frequency band associated with the sympathetic nervous system in the EDA signal during exercise. Eighteen healthy subjects underwent a sub-maximal exercise test, including a resting period, walking, and running, until achieving 85% of maximum heart rate. Both EDA and ECG data were measured simultaneously for all subjects. The ECG was used to monitor subjects’ instantaneous heart rate, which was used to set the experiment’s end point. We found that the upper bound of the frequency band (Fmax) containing the EDA spectral power significantly shifted to higher frequencies when subjects underwent prolonged low-intensity (Fmax ~ 0.28) and vigorous-intensity exercise (Fmax ~ 0.37 Hz) when compared to the resting condition. In summary, we have found shifting of the sympathetic dynamics to higher frequencies in the EDA signal when subjects undergo physical activity. PMID:29856815

Asymptotic theory of time varying networks with burstiness and heterogeneous activation patterns

NASA Astrophysics Data System (ADS)

Burioni, Raffaella; Ubaldi, Enrico; Vezzani, Alessandro

2017-05-01

The recent availability of large-scale, time-resolved and high quality digital datasets has allowed for a deeper understanding of the structure and properties of many real-world networks. The empirical evidence of a temporal dimension prompted the switch of paradigm from a static representation of networks to a time varying one. In this work we briefly review the framework of time-varying-networks in real world social systems, especially focusing on the activity-driven paradigm. We develop a framework that allows for the encoding of three generative mechanisms that seem to play a central role in the social networks’ evolution: the individual’s propensity to engage in social interactions, its strategy in allocate these interactions among its alters and the burstiness of interactions amongst social actors. The functional forms and probability distributions encoding these mechanisms are typically data driven. A natural question arises if different classes of strategies and burstiness distributions, with different local scale behavior and analogous asymptotics can lead to the same long time and large scale structure of the evolving networks. We consider the problem in its full generality, by investigating and solving the system dynamics in the asymptotic limit, for general classes of ties allocation mechanisms and waiting time probability distributions. We show that the asymptotic network evolution is driven by a few characteristics of these functional forms, that can be extracted from direct measurements on large datasets.

Study on photoemission surface of varied doping GaN photocathode

NASA Astrophysics Data System (ADS)

Qiao, Jianliang; Du, Ruijuan; Ding, Huan; Gao, Youtang; Chang, Benkang

2014-09-01

For varied doping GaN photocathode, from bulk to surface the doping concentrations are distributed from high to low. The varied doping GaN photocathode may produce directional inside electric field within the material, so the higher quantum efficiency can be obtained. The photoemission surface of varied doping GaN photocathode is very important to the high quantum efficiency, but the forming process of the surface state after Cs activation or Cs/O activation has been not known completely. Encircling the photoemission mechanism of varied GaN photocathode, considering the experiment phenomena during the activation and the successful activation results, the varied GaN photocathode surface model [GaN(Mg):Cs]:O-Cs after activation with cesium and oxygen was given. According to GaN photocathode activation process and the change of electronic affinity, the comparatively ideal NEA property can be achieved by Cs or Cs/O activation, and higher quantum efficiency can be obtained. The results show: The effective NEA characteristic of GaN can be gotten only by Cs. [GaN(Mg):Cs] dipoles form the first dipole layer, the positive end is toward the vacuum side. In the activation processing with Cs/O, the second dipole layer is formed by O-Cs dipoles, A O-Cs dipole includes one oxygen atom and two Cs atoms, and the positive end is also toward the vacuum side thus the escape of electrons can be promoted.

Novel CDK inhibition profiles of structurally varied 1-aza-9-oxafluorenes.

PubMed

Voigt, Burkhardt; Meijer, Laurent; Lozach, Olivier; Schächtele, Christoph; Totzke, Frank; Hilgeroth, Andreas

2005-02-01

A series of 1-aza-9-oxafluorenes with functionally varied 3-substituents have been prepared from N-phenoxycarbonyl-4-phenyl-1,4-dihydropyridines and p-benzoquinone and biologically evaluated as inhibitors of various cyclin-dependant kinases. The absence of a 3-hydrogen bond acceptor function leads to a complete loss of inhibitory activity. Differing hydrogen bond acceptor functions surprisingly cause significant shifts in the selectivity of inhibition profiles.

Scaling properties in time-varying networks with memory

NASA Astrophysics Data System (ADS)

Kim, Hyewon; Ha, Meesoon; Jeong, Hawoong

2015-12-01

The formation of network structure is mainly influenced by an individual node's activity and its memory, where activity can usually be interpreted as the individual inherent property and memory can be represented by the interaction strength between nodes. In our study, we define the activity through the appearance pattern in the time-aggregated network representation, and quantify the memory through the contact pattern of empirical temporal networks. To address the role of activity and memory in epidemics on time-varying networks, we propose temporal-pattern coarsening of activity-driven growing networks with memory. In particular, we focus on the relation between time-scale coarsening and spreading dynamics in the context of dynamic scaling and finite-size scaling. Finally, we discuss the universality issue of spreading dynamics on time-varying networks for various memory-causality tests.

Are secular correlations between sunspots, geomagnetic activity, and global temperature significant?

USGS Publications Warehouse

Love, J.J.; Mursula, K.; Tsai, V.C.; Perkins, D.M.

2011-01-01

Recent studies have led to speculation that solar-terrestrial interaction, measured by sunspot number and geomagnetic activity, has played an important role in global temperature change over the past century or so. We treat this possibility as an hypothesis for testing. We examine the statistical significance of cross-correlations between sunspot number, geomagnetic activity, and global surface temperature for the years 1868-2008, solar cycles 11-23. The data contain substantial autocorrelation and nonstationarity, properties that are incompatible with standard measures of cross-correlational significance, but which can be largely removed by averaging over solar cycles and first-difference detrending. Treated data show an expected statistically- significant correlation between sunspot number and geomagnetic activity, Pearson p < 10-4, but correlations between global temperature and sunspot number (geomagnetic activity) are not significant, p = 0.9954, (p = 0.8171). In other words, straightforward analysis does not support widely-cited suggestions that these data record a prominent role for solar-terrestrial interaction in global climate change. With respect to the sunspot-number, geomagnetic-activity, and global-temperature data, three alternative hypotheses remain difficult to reject: (1) the role of solar-terrestrial interaction in recent climate change is contained wholly in long-term trends and not in any shorter-term secular variation, or, (2) an anthropogenic signal is hiding correlation between solar-terrestrial variables and global temperature, or, (3) the null hypothesis, recent climate change has not been influenced by solar-terrestrial interaction. ?? 2011 by the American Geophysical Union.

Are secular correlations between sunspots, geomagnetic activity, and global temperature significant?

NASA Astrophysics Data System (ADS)

Love, Jeffrey J.; Mursula, Kalevi; Tsai, Victor C.; Perkins, David M.

2011-11-01

Recent studies have led to speculation that solar-terrestrial interaction, measured by sunspot number and geomagnetic activity, has played an important role in global temperature change over the past century or so. We treat this possibility as an hypothesis for testing. We examine the statistical significance of cross-correlations between sunspot number, geomagnetic activity, and global surface temperature for the years 1868-2008, solar cycles 11-23. The data contain substantial autocorrelation and nonstationarity, properties that are incompatible with standard measures of cross-correlational significance, but which can be largely removed by averaging over solar cycles and first-difference detrending. Treated data show an expected statistically-significant correlation between sunspot number and geomagnetic activity, Pearson p < 10-4, but correlations between global temperature and sunspot number (geomagnetic activity) are not significant, p = 0.9954, (p = 0.8171). In other words, straightforward analysis does not support widely-cited suggestions that these data record a prominent role for solar-terrestrial interaction in global climate change. With respect to the sunspot-number, geomagnetic-activity, and global-temperature data, three alternative hypotheses remain difficult to reject: (1) the role of solar-terrestrial interaction in recent climate change is contained wholly in long-term trends and not in any shorter-term secular variation, or, (2) an anthropogenic signal is hiding correlation between solar-terrestrial variables and global temperature, or, (3) the null hypothesis, recent climate change has not been influenced by solar-terrestrial interaction.

Weather and children's physical activity; how and why do relationships vary between countries?

PubMed

Harrison, Flo; Goodman, Anna; van Sluijs, Esther M F; Andersen, Lars Bo; Cardon, Greet; Davey, Rachel; Janz, Kathleen F; Kriemler, Susi; Molloy, Lynn; Page, Angie S; Pate, Russ; Puder, Jardena J; Sardinha, Luis B; Timperio, Anna; Wedderkopp, Niels; Jones, Andy P

2017-05-30

Globally most children do not engage in enough physical activity. Day length and weather conditions have been identified as determinants of physical activity, although how they may be overcome as barriers is not clear. We aim to examine if and how relationships between children's physical activity and weather and day length vary between countries and identify settings in which children were better able to maintain activity levels given the weather conditions they experienced. In this repeated measures study, we used data from 23,451 participants in the International Children's Accelerometry Database (ICAD). Daily accelerometer-measured physical activity (counts per minute; cpm) was matched to local weather conditions and the relationships assessed using multilevel regression models. Multilevel models accounted for clustering of days within occasions within children within study-cities, and allowed us to explore if and how the relationships between weather variables and physical activity differ by setting. Increased precipitation and wind speed were associated with decreased cpm while better visibility and more hours of daylight were associated with increased cpm. Models indicated that increases in these variables resulted in average changes in mean cpm of 7.6/h of day length, -13.2/cm precipitation, 10.3/10 km visibility and -10.3/10kph wind speed (all p < 0.01). Temperature showed a cubic relationship with cpm, although between 0 and 20 degrees C the relationship was broadly linear. Age showed interactions with temperature and precipitation, with the associations larger among younger children. In terms of geographic trends, participants from Northern European countries and Melbourne, Australia were the most active, and also better maintained their activity levels given the weather conditions they experienced compared to those in the US and Western Europe. We found variation in the relationship between weather conditions and physical activity between ICAD

Teaching physical activities to students with significant disabilities using video modeling.

PubMed

Cannella-Malone, Helen I; Mizrachi, Sharona V; Sabielny, Linsey M; Jimenez, Eliseo D

2013-06-01

The objective of this study was to examine the effectiveness of video modeling on teaching physical activities to three adolescents with significant disabilities. The study implemented a multiple baseline across six physical activities (three per student): jumping rope, scooter board with cones, ladder drill (i.e., feet going in and out), ladder design (i.e., multiple steps), shuttle run, and disc ride. Additional prompt procedures (i.e., verbal, gestural, visual cues, and modeling) were implemented within the study. After the students mastered the physical activities, we tested to see if they would link the skills together (i.e., complete an obstacle course). All three students made progress learning the physical activities, but only one learned them with video modeling alone (i.e., without error correction). Video modeling can be an effective tool for teaching students with significant disabilities various physical activities, though additional prompting procedures may be needed.

Dynamic Factor Analysis Models with Time-Varying Parameters

ERIC Educational Resources Information Center

Chow, Sy-Miin; Zu, Jiyun; Shifren, Kim; Zhang, Guangjian

2011-01-01

Dynamic factor analysis models with time-varying parameters offer a valuable tool for evaluating multivariate time series data with time-varying dynamics and/or measurement properties. We use the Dynamic Model of Activation proposed by Zautra and colleagues (Zautra, Potter, & Reich, 1997) as a motivating example to construct a dynamic factor…

Behaviors and kinetics of toluene adsorption-desorption on activated carbons with varying pore structure.

PubMed

Yang, Xi; Yi, Honghong; Tang, Xiaolong; Zhao, Shunzheng; Yang, Zhongyu; Ma, Yueqiang; Feng, Tiecheng; Cui, Xiaoxu

2018-05-01

This work was undertaken to investigate the behaviors and kinetics of toluene adsorption and desorption on activated carbons with varying pore structure. Five kinds of activated carbon from different raw materials were selected. Adsorption isotherms and breakthrough curves for toluene were measured. Langmuir and Freundlich equations were fitted to the equilibrium data, and the Freundlich equation was more suitable for simulating toluene adsorption. The process consisted of monolayer, multilayer and partial active site adsorption types. The effect of the pore structure of the activated carbons on toluene adsorption capacity was investigated. The quasi-first-order model was more suitable for describing the process than the quasi-second-order model. The adsorption data was also modeled by the internal particle diffusion model and it was found that the adsorption process could be divided into three stages. In the external surface adsorption process, the rate depended on the specific surface area. During the particle diffusion stage, pore structure and volume were the main factors affecting adsorption rate. In the final equilibrium stage, the rate was determined by the ratio of meso- and macro-pores to total pore volume. The rate over the whole adsorption process was dominated by the toluene concentration. The desorption behavior of toluene on activated carbons was investigated, and the process was divided into heat and mass transfer parts corresponding to emission and diffusion mechanisms, respectively. Physical adsorption played the main role during the adsorption process. Copyright © 2017. Published by Elsevier B.V.

Facing two faces: Defense activation varies as a function of personal relevance.

PubMed

Bublatzky, Florian; Alpers, Georg W

2017-04-01

It can be unsettling to be watched by a group of people, and when they express anger or hostility, this can prime defensive behavior. In contrast, when others smile at us, this may be comforting. This study tested to which degree the impact of facial expressions (happy, neutral, and angry) varies with the personal relevance of a social situation. Modelling a triadic situation, two faces looked either directly at the participant, faced each other, or they were back to back. Results confirmed that this variation constitutes a gradient of personal relevance (directed frontally > towards > away), as reflected by corresponding defensive startle modulation and autonomic nervous system activity. This gradient was particularly pronounced for angry faces and it was steeper in participants with higher levels of social anxiety. Thus, sender-recipient constellations modulate the processing of facial emotions in favor of adequate behavioral responding (e.g., avoidance) in group settings. Copyright © 2017 Elsevier B.V. All rights reserved.

Social contagions on time-varying community networks

NASA Astrophysics Data System (ADS)

Liu, Mian-Xin; Wang, Wei; Liu, Ying; Tang, Ming; Cai, Shi-Min; Zhang, Hai-Feng

2017-05-01

Time-varying community structures exist widely in real-world networks. However, previous studies on the dynamics of spreading seldom took this characteristic into account, especially those on social contagions. To study the effects of time-varying community structures on social contagions, we propose a non-Markovian social contagion model on time-varying community networks based on the activity-driven network model. A mean-field theory is developed to analyze the proposed model. Through theoretical analyses and numerical simulations, two hierarchical features of the behavior adoption processes are found. That is, when community strength is relatively large, the behavior can easily spread in one of the communities, while in the other community the spreading only occurs at higher behavioral information transmission rates. Meanwhile, in spatial-temporal evolution processes, hierarchical orders are observed for the behavior adoption. Moreover, under different information transmission rates, three distinctive patterns are demonstrated in the change of the whole network's final adoption proportion along with the growing community strength. Within a suitable range of transmission rate, an optimal community strength can be found that can maximize the final adoption proportion. Finally, compared with the average activity potential, the promoting or inhibiting of social contagions is much more influenced by the number of edges generated by active nodes.

Active spectral sensor evaluation under varying conditions

USDA-ARS?s Scientific Manuscript database

Plant stress has been estimated by spectral signature using both passive and active sensors. As optical sensors measure reflected light from a target, changes in illumination characteristics critically affect sensor response. Active sensors are of benefit in minimizing uncontrolled illumination effe...

PRN 96-8: Toxicologically Significant Levels of Pesticide Active Ingredients

EPA Pesticide Factsheets

This notice sets out EPA's interpretation of the term toxicologically significant as it applies to contaminants in pesticide products that are also pesticide active ingredients. It provides risk-based concentration levels of such contaminants.

The Varied Roles of Notch in Cancer

PubMed Central

Aster, Jon C.; Pear, Warren S.; Blacklow, Stephen C.

2018-01-01

Notch receptors influence cellular behavior by participating in a seemingly simple signaling pathway, but outcomes produced by Notch signaling are remarkably varied depending on signal dose and cell context. Here, after briefly reviewing new insights into physiologic mechanisms of Notch signaling in healthy tissues and defects in Notch signaling that contribute to congenital disorders and viral infection, we discuss the varied roles of Notch in cancer, focusing on cell autonomous activities that may be either oncogenic or tumor suppressive. PMID:27959635

Linear-parameter-varying gain-scheduled control of aerospace systems

NASA Astrophysics Data System (ADS)

Barker, Jeffrey Michael

The dynamics of many aerospace systems vary significantly as a function of flight condition. Robust control provides methods of guaranteeing performance and stability goals across flight conditions. In mu-syntthesis, changes to the dynamical system are primarily treated as uncertainty. This method has been successfully applied to many control problems, and here is applied to flutter control. More recently, two techniques for generating robust gain-scheduled controller have been developed. Linear fractional transformation (LFT) gain-scheduled control is an extension of mu-synthesis in which the plant and controller are explicit functions of parameters measurable in real-time. This LFT gain-scheduled control technique is applied to the Benchmark Active Control Technology (BACT) wing, and compared with mu-synthesis control. Linear parameter-varying (LPV) gain-scheduled control is an extension of Hinfinity control to parameter varying systems. LPV gain-scheduled control directly incorporates bounds on the rate of change of the scheduling parameters, and often reduces conservatism inherent in LFT gain-scheduled control. Gain-scheduled LPV control of the BACT wing compares very favorably with the LFT controller. Gain-scheduled LPV controllers are generated for the lateral-directional and longitudinal axes of the Innovative Control Effectors (ICE) aircraft and implemented in nonlinear simulations and real-time piloted nonlinear simulations. Cooper-Harper and pilot-induced oscillation ratings were obtained for an initial design, a reference aircraft and a redesign. Piloted simulation results for the initial LPV gain-scheduled control of the ICE aircraft are compared with results for a conventional fighter aircraft in discrete pitch and roll angle tracking tasks. The results for the redesigned controller are significantly better than both the previous LPV controller and the conventional aircraft.

The catalytic activity of a recombinant single chain variable fragment nucleic acid-hydrolysing antibody varies with fusion tag and expression host.

PubMed

Lee, Joungmin; Kim, Minjae; Seo, Youngsil; Lee, Yeonjin; Park, Hyunjoon; Byun, Sung June; Kwon, Myung-Hee

2017-11-01

The antigen-binding properties of single chain Fv antibodies (scFvs) can vary depending on the position and type of fusion tag used, as well as the host cells used for expression. The issue is even more complicated with a catalytic scFv antibody that binds and hydrolyses a specific antigen. Herein, we investigated the antigen-binding and -hydrolysing activities of the catalytic anti-nucleic acid antibody 3D8 scFv expressed in Escherichia coli or HEK293f cells with or without additional amino acid residues at the N- and C-termini. DNA-binding activity was retained in all recombinant forms. However, the DNA-hydrolysing activity varied drastically between forms. The DNA-hydrolysing activity of E. coli-derived 3D8 scFvs was not affected by the presence of a C-terminal human influenza haemagglutinin (HA) or His tag. By contrast, the activity of HEK293f-derived 3D8 scFvs was completely lost when additional residues were included at the N-terminus and/or when a His tag was incorporated at the C-terminus, whereas a HA tag at the C-terminus did not diminish activity. Thus, we demonstrate that the antigen-binding and catalytic activities of a catalytic antibody can be separately affected by the presence of additional residues at the N- and C-termini, and by the host cell type. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Comparative research on the influence of varied Al component on the active layer of AlGaN photocathode

NASA Astrophysics Data System (ADS)

He, Minyou; Chen, Liang; Su, Lingai; Yin, Lin; Qian, Yunsheng

2017-06-01

To theoretically research the influence of a varied Al component on the active layer of AlGaN photocathodes, the first principle based on density functional theory is used to calculate the formation energy and band structure of Al x Ga1-x N with x at 0, 0.125, 0.25, 0.325, and 0.5. The calculation results show that the formation energy declines along with the Al component rise, while the band gap is increasing with Al component increasing. Al x Ga1-x N with x at 0, 0.125, 0.25, 0.325, and 0.5 are direct band gap semiconductors, and their absorption coefficient curves have the same variation tendency. For further study, we designed two kinds of reflection-mode AlGaN photocathode samples. Sample 1 has an Al x Ga1-x N active layer with varied Al component ranging from 0.5 to 0 and decreasing from the bulk to the surface, while sample 2 has an Al x Ga1-x N active layer with the fixed Al component of 0.25. Using the multi-information measurement system, we measured the spectral response of the activated samples at room temperature. Their photocathode parameters were obtained by fitting quantum efficiency curves. Results show that sample 1 has a better spectral response than sample 2 at the range of short-wavelength. This work provides a reference for the structure design of the AlGaN photocathode. Project supported by the National Natural Science Foundation of China (Nos. 61308089, 6144005) and the Public Technology Applied Research Project of Zhejiang Province (No. 2013C31068).

The temporal structures and functional significance of scale-free brain activity

PubMed Central

He, Biyu J.; Zempel, John M.; Snyder, Abraham Z.; Raichle, Marcus E.

2010-01-01

SUMMARY Scale-free dynamics, with a power spectrum following P ∝ f-β, are an intrinsic feature of many complex processes in nature. In neural systems, scale-free activity is often neglected in electrophysiological research. Here, we investigate scale-free dynamics in human brain and show that it contains extensive nested frequencies, with the phase of lower frequencies modulating the amplitude of higher frequencies in an upward progression across the frequency spectrum. The functional significance of scale-free brain activity is indicated by task performance modulation and regional variation, with β being larger in default network and visual cortex and smaller in hippocampus and cerebellum. The precise patterns of nested frequencies in the brain differ from other scale-free dynamics in nature, such as earth seismic waves and stock market fluctuations, suggesting system-specific generative mechanisms. Our findings reveal robust temporal structures and behavioral significance of scale-free brain activity and should motivate future study on its physiological mechanisms and cognitive implications. PMID:20471349

Simple reaction time to the onset of time-varying sounds.

PubMed

Schlittenlacher, Josef; Ellermeier, Wolfgang

2015-10-01

Although auditory simple reaction time (RT) is usually defined as the time elapsing between the onset of a stimulus and a recorded reaction, a sound cannot be specified by a single point in time. Therefore, the present work investigates how the period of time immediately after onset affects RT. By varying the stimulus duration between 10 and 500 msec, this critical duration was determined to fall between 32 and 40 milliseconds for a 1-kHz pure tone at 70 dB SPL. In a second experiment, the role of the buildup was further investigated by varying the rise time and its shape. The increment in RT for extending the rise time by a factor of ten was about 7 to 8 msec. There was no statistically significant difference in RT between a Gaussian and linear rise shape. A third experiment varied the modulation frequency and point of onset of amplitude-modulated tones, producing onsets at different initial levels with differently rapid increase or decrease immediately afterwards. The results of all three experiments results were explained very well by a straightforward extension of the parallel grains model (Miller and Ulrich Cogn. Psychol. 46, 101-151, 2003), a probabilistic race model employing many parallel channels. The extension of the model to time-varying sounds made the activation of such a grain depend on intensity as a function of time rather than a constant level. A second approach by mechanisms known from loudness produced less accurate predictions.

Multistability of memristive Cohen-Grossberg neural networks with non-monotonic piecewise linear activation functions and time-varying delays.

PubMed

Nie, Xiaobing; Zheng, Wei Xing; Cao, Jinde

2015-11-01

The problem of coexistence and dynamical behaviors of multiple equilibrium points is addressed for a class of memristive Cohen-Grossberg neural networks with non-monotonic piecewise linear activation functions and time-varying delays. By virtue of the fixed point theorem, nonsmooth analysis theory and other analytical tools, some sufficient conditions are established to guarantee that such n-dimensional memristive Cohen-Grossberg neural networks can have 5(n) equilibrium points, among which 3(n) equilibrium points are locally exponentially stable. It is shown that greater storage capacity can be achieved by neural networks with the non-monotonic activation functions introduced herein than the ones with Mexican-hat-type activation function. In addition, unlike most existing multistability results of neural networks with monotonic activation functions, those obtained 3(n) locally stable equilibrium points are located both in saturated regions and unsaturated regions. The theoretical findings are verified by an illustrative example with computer simulations. Copyright © 2015 Elsevier Ltd. All rights reserved.

Are all sport activities equal? A systematic review of how youth psychosocial experiences vary across differing sport activities.

PubMed

Evans, M Blair; Allan, Veronica; Erickson, Karl; Martin, Luc J; Budziszewski, Ross; Côté, Jean

2017-02-01

Models of sport development often support the assumption that young athletes' psychosocial experiences differ as a result of seemingly minor variations in how their sport activities are designed (eg, participating in team or individual sport; sampling many sports or specialising at an early age). This review was conducted to systematically search sport literature and explore how the design of sport activities relates to psychosocial outcomes. Systematic search, followed by data extraction and synthesis. The Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines were applied and a coding sheet was used to extract article information and code for risk of bias. Academic databases and manual search of peer-reviewed journals. Search criteria determined eligibility primarily based on the sample (eg, ages 7 through 17 years) and study design (eg, measured psychosocial constructs). 35 studies were located and were classified within three categories: (1) sport types, (2) sport settings, and (3) individual patterns of sport involvement. These studies represented a wide range of scores when assessed for risk of bias and involved an array of psychosocial constructs, with the most prevalent investigations predicting outcomes such as youth development, self-esteem and depression by comparing (1) team or individual sport participants and (2) youth with varying amounts of sport involvement. As variations in sport activities impact youth sport experiences, it is vital for researchers to carefully describe and study these factors, while practitioners may use the current findings when designing youth sport programmes. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

PCB concentrations and activity of sea lamprey Petromyzon marinus vary by sex

USGS Publications Warehouse

Madenjian, Charles P.; Johnson, Nicholas S.; Binder, Thomas R.; Rediske, Richard R.; O'Keefe, James P.

2013-01-01

We determined the polychlorinated biphenyl (PCB) concentrations of 40 male and 40 female adult sea lampreys Petromyzon marinus captured in the Cheboygan River, a tributary to Lake Huron, during May 2011. In addition, we performed a laboratory experiment using passive integrated transponder tags to determine whether male adult sea lampreys were more active than female adult sea lampreys. Sex had a significant effect on PCB concentration, and PCB concentration at a given level of sea lamprey condition was approximately 25 % greater in males than in females. Adjusting for the difference in condition between the sexes, males averaged a 17 % greater PCB concentration compared with females. Results from the laboratory experiment indicated that males were significantly more active than females. The observed sex difference in PCB concentrations was not due to female sea lampreys releasing eggs at spawning because the sea lamprey is semelparous, and we caught the sea lampreys before spawning. Rather, we attributed the sex difference in PCB concentrations to a greater rate of energy expenditure in males compared with females. We proposed that this greater rate of energy expenditure was likely due to greater activity. Our laboratory experiment results supported this hypothesis. A greater resting metabolic rate may also have contributed to a greater rate of energy expenditure. Our findings should eventually be applicable toward improving control of sea lamprey, a pest responsible for considerable damage to fisheries in lakes where it is not native.

Significant changes in physical activity among pregnant women in the UK as assessed by accelerometry and self-reported activity.

PubMed

Rousham, E K; Clarke, P E; Gross, H

2006-03-01

Research on the impact of maternal physical activity on pregnancy outcomes has often employed subjective measures of physical activity obtained by diary or questionnaire. This study investigates the feasibility of using accelerometry as an objective measure of physical activity of pregnant women compared with subjective data obtained via activity recall among pregnant women. Activity data were collected prospectively on 57 women at 12, 16, 25, 34 and 38 weeks of gestation. Total daily physical activity was assessed by ambulatory accelerometer and activity interview (self-report). Maternal personality variables (health value, extroversion) were assessed by established scales. Leicestershire, UK. Pregnant women were recruited by voluntary participation via antenatal booking clinics. In all, 64 pregnant women with low-risk pregnancy were enrolled onto the study, of whom 57 completed the study. Mean 24 h physical activity levels (PAL) decreased significantly from second to third trimester as assessed by self-report interview (1.51-1.29 Metabolic Equivalent TEE-h/day, P<0.01) and accelerometry (200.05-147.42 counts/min, P<0.01). The correlation between the two measures declined as pregnancy progressed (r value ranging from 0.55 to 0.08). Compliance with the accelerometers declined from 90% at 12 weeks to 47% at 34 weeks (P<0.01). Compliance with the self-report interviews was 100%. Those who fully complied with the accelerometry demonstrated a significantly higher health value (P<0.05) and a significantly greater level of extroversion (P<0.05) than those who did not. Accelerometers and self-reported activity interviews both indicated a significant decline in PAL during pregnancy. Although subjects showed a willingness to use both methods, accelerometers resulted in variable compliance with 72 h monitoring. Both techniques may be limited by the need to measure low levels of physical activity during the third trimester. Cambridge Neurotechnology Ltd, UK, assisted with the

Annual physical examination reports vary by gender once teenagers become sexually active

PubMed Central

Marcell, Arik V.; Matson, Pam; Ellen, Jonathan M.; Ford, Carol A.

2010-01-01

Introduction Few sexually active male adolescents receive sexual/reproductive health (SRH) services. We examine whether the association between adolescents’ sexual behavior status and physical examination over time can help us understand why. Methods We conducted longitudinal cohort analysis of the National Longitudinal Study of Adolescent Health with 9239 adolescents who completed the baseline school (1994/95) and Wave 2 (1996) follow-up surveys approximately 1.5 years later (retention rate=71%). We fit logistic regression models with random effects to estimate individual odds of reporting a physical examination in the past 12 months at follow-up, as compared to baseline, stratified by sexual behavior status and gender, and adjusting for sociodemographic and healthcare access factors. Results 34.5% males and 38.2% females reported experiencing vaginal intercourse by follow-up, and 22.4% males and 24.7% females reported first experiencing intercourse during the study. Among sexually active adolescents, about half reported annual exams and one-fifth no exams. Among females, baseline to follow-up exam reports significantly increased in: sex initiators (adjusted Odds Ratio [95% confidence interval]=2.09 [1.66–2.64]); those reporting sex at both times (2.16 [1.51–3.09]); and those reporting no sex either time (2.47 [2.00–3.04]). Among males, baseline to follow-up exam reports significantly increased in those reporting no sex either time (1.57 [1.26–1.96]) and showed increasing trends in sex initiators (1.27 [0.92–1.76]). Discussion A majority of sexually active adolescents report annual physical exams over time. Providers should not miss opportunities to deliver evidence-based SRH to sexually active adolescents. Future efforts are needed to increase all adolescents’ access to SRH services. PMID:21700156

Functional significance of the pattern of renal sympathetic nerve activation.

PubMed

Dibona, G F; Sawin, L L

1999-08-01

To assess the renal functional significance of the pattern of renal sympathetic nerve activation, computer-generated stimulus patterns (delivered at constant integrated voltage) were applied to the decentralized renal sympathetic nerve bundle and renal hemodynamic and excretory responses determined in anesthetized rats. When delivered at the same integrated voltage, stimulus patterns resembling those observed in in vivo multifiber recordings of renal sympathetic nerve activity (diamond-wave patterns) produced greater renal vasoconstrictor responses than conventional square-wave patterns. Within diamond-wave patterns, increasing integrated voltage by increasing amplitude produced twofold greater renal vasoconstrictor responses than by increasing duration. With similar integrated voltages that were subthreshold for renal vasoconstriction, neither diamond- nor square-wave pattern altered glomerular filtration rate, whereas diamond- but not square-wave pattern reversibly decreased urinary sodium excretion by 25 +/- 3%. At the same number of pulses per second, intermittent stimulation produced faster and greater renal vasoconstriction than continuous stimulation. At the same number of pulses per second, increases in rest period during intermittent stimulation proportionally augmented the renal vasoconstrictor response compared with that observed with continuous stimulation; the maximum augmentation of 55% occurred at a rest period of 500 ms. These results indicate that the pattern of renal sympathetic nerve stimulation (activity) significantly influences the rapidity, magnitude, and selectivity of the renal vascular and tubular responses.

[Cytomixis, its nature, significance and the cytological consequences].

PubMed

Kravets, E A

2012-01-01

Cytomixis is the widespread natural process of intercellular interaction which is characteristic for vegetative and generative tissues in both normal and pathological conditions. The origin significance and genetic control cytomixis still remain not completely clear. The popularity of view of the pathological nature of cytomixis based on its peculiar plants with genetic instability and impaired homeostasis. In the genetic control of cytomixis seem to be involved meiotic genes which are responsible for segregation and organization of chromosomes. Their activity is modified by environmental factors through signal transduction. It is assumed via cytomixis, from one side, the informational contact can be reached and meiosis and gametogenesis are synchronized, with another, increase of the genetic variety and level of the heterozygosis of microsporocytes. The activity of cytomixis varies over wide limits. The greatest influence on its activity have mutagenesis hybridization and polyploidy. In this context cytomixis can fulfill the function of cell selection which is activated by exceeding of the threshold level of the microsporocyte damages (or genetical disbalance).

Learning Time-Varying Coverage Functions

PubMed Central

Du, Nan; Liang, Yingyu; Balcan, Maria-Florina; Song, Le

2015-01-01

Coverage functions are an important class of discrete functions that capture the law of diminishing returns arising naturally from applications in social network analysis, machine learning, and algorithmic game theory. In this paper, we propose a new problem of learning time-varying coverage functions, and develop a novel parametrization of these functions using random features. Based on the connection between time-varying coverage functions and counting processes, we also propose an efficient parameter learning algorithm based on likelihood maximization, and provide a sample complexity analysis. We applied our algorithm to the influence function estimation problem in information diffusion in social networks, and show that with few assumptions about the diffusion processes, our algorithm is able to estimate influence significantly more accurately than existing approaches on both synthetic and real world data. PMID:25960624

Learning Time-Varying Coverage Functions.

PubMed

Du, Nan; Liang, Yingyu; Balcan, Maria-Florina; Song, Le

2014-12-08

Coverage functions are an important class of discrete functions that capture the law of diminishing returns arising naturally from applications in social network analysis, machine learning, and algorithmic game theory. In this paper, we propose a new problem of learning time-varying coverage functions, and develop a novel parametrization of these functions using random features. Based on the connection between time-varying coverage functions and counting processes, we also propose an efficient parameter learning algorithm based on likelihood maximization, and provide a sample complexity analysis. We applied our algorithm to the influence function estimation problem in information diffusion in social networks, and show that with few assumptions about the diffusion processes, our algorithm is able to estimate influence significantly more accurately than existing approaches on both synthetic and real world data.

Annual physical examination reports vary by gender once teenagers become sexually active.

PubMed

Marcell, Arik V; Matson, Pam; Ellen, Jonathan M; Ford, Carol A

2011-07-01

Few sexually active male adolescents receive sexual and reproductive health (SRH) services. To understand this, we examined the association between sexual behavior status and physical examination of the adolescents over time. We conducted longitudinal cohort analysis of the National Longitudinal Study of Adolescent Health with 9,239 adolescents who completed the baseline school (1994/1995) and wave 2 (1996) follow-up surveys approximately 1.5 years later (retention rate = 71%). The logistic regression models were fitted with random effects to estimate individual odds of reporting a physical examination in the past 12 months at follow-up, compared with baseline, stratified by sexual behavior status and gender, and adjusting for sociodemographic and healthcare access factors. In all, 34.5% of male and 38.2% of female adolescents reported experiencing vaginal intercourse by follow-up, and 22.4% of male and 24.7% of female adolescents reported first experiencing intercourse during the study period. Among sexually active adolescents, about half reported having annual physical examinations and one-fifth reported not having any physical examinations. Among female adolescents, baseline to follow-up examination reports significantly increased in the following: sex initiators (adjusted odds ratio [OR] = 2.09, 95% confidence interval [CI] = 1.66-2.64); those reporting sex at both times (OR = 2.16, CI = 1.51-3.09); and those reporting no sex either time (OR = 2.47, CI = 2.00-3.04). Among male adolescents, baseline to follow-up examination reports significantly increased in those reporting no sex either time (OR = 1.57, CI = 1.26-1.96) and showed increasing trends in sex initiators (OR = 1.27, CI = .92-1.76). A majority of sexually active adolescents report annual physical examinations over time. Providers should not miss opportunities to deliver evidence-based SRH to sexually active adolescents. Future efforts are needed to increase access of all adolescents to SRH services

Using animal models to determine the significance of complement activation in Alzheimer's disease

PubMed Central

Loeffler, David A

2004-01-01

Complement inflammation is a major inflammatory mechanism whose function is to promote the removal of microorganisms and the processing of immune complexes. Numerous studies have provided evidence for an increase in this process in areas of pathology in the Alzheimer's disease (AD) brain. Because complement activation proteins have been demonstrated in vitro to exert both neuroprotective and neurotoxic effects, the significance of this process in the development and progression of AD is unclear. Studies in animal models of AD, in which brain complement activation can be experimentally altered, should be of value for clarifying this issue. However, surprisingly little is known about complement activation in the transgenic animal models that are popular for studying this disorder. An optimal animal model for studying the significance of complement activation on Alzheimer's – related neuropathology should have complete complement activation associated with senile plaques, neurofibrillary tangles (if present), and dystrophic neurites. Other desirable features include both classical and alternative pathway activation, increased neuronal synthesis of native complement proteins, and evidence for an increase in complement activation prior to the development of extensive pathology. In order to determine the suitability of different animal models for studying the role of complement activation in AD, the extent of complement activation and its association with neuropathology in these models must be understood. PMID:15479474

Influence of gold nanoparticles of varying size in improving the lipase activity within cationic reverse micelles.

PubMed

Maiti, Subhabrata; Das, Dibyendu; Shome, Anshupriya; Das, Prasanta Kumar

2010-02-08

Herein, we report the effect of gold nanoparticles (GNPs) in enhancing lipase activity in reverse micelles of cetyltrimethylammonium bromide (CTAB)/water/isooctane/n-hexanol. The size and concentration of the nanoparticles were varied and their specific roles were assessed in detail. An overall enhancement of activity was observed in the GNP-doped CTAB reverse micelles. The improvement in activity becomes more prominent with increasing concentration and size of the GNPs (0-52 microM and ca. 3-30 nm, respectively). The observed highest lipase activity (k(2)=1070+/-12 cm(3) g(-1) s(-1)) in GNP-doped CTAB reverse micelles ([GNP]: 52 microm, ca. 20 nm) is 2.5-fold higher than in CTAB reverse micelles without GNPs. Improvement in the lipase activity is only specific to the GNP-doped reverse micellar media, whereas GNP deactivates and structurally deforms the enzyme in aqueous media. The reason for this activation is probably due to the formation of larger-sized reverse micelles in which the GNP acts as a polar core and the surfactants aggregate around the nanoparticle ('GNP pool') instead of only water. Lipase at the augmented interface of the GNP-doped reverse micelle showed improved activity because of enhancement in both the substrate and enzyme concentrations and increased flexibility in the lipase conformation. The extent of the activation is greater in the case of the larger-sized GNPs. A correlation has been established between the activity of lipase and its secondary structure by using circular dichroism and FTIR spectroscopic analysis. The generalized influence of GNP is verified in the reverse micelles of another surfactant, namely, cetyltripropylammonium bromide (CTPAB). TEM, dynamic light scattering (DLS), and UV/Vis spectroscopic analysis were utilized to characterize the GNPs and the organized aggregates. For the first time, CTAB-based reverse micelles have been found to be an excellent host for lipase simply by doping with appropriately sized GNPs.

Striving to be known by significant others: automatic activation of self-verification goals in relationship contexts.

PubMed

Kraus, Michael W; Chen, Serena

2009-07-01

Extending research on the automatic activation of goals associated with significant others, the authors hypothesized that self-verification goals typically pursued with significant others are automatically elicited when a significant-other representation is activated. Supporting this hypothesis, the activation of a significant-other representation through priming (Experiments 1 and 3) or through a transference encounter (Experiment 2) led participants to seek feedback that verifies their preexisting self-views. Specifically, significant-other primed participants desired self-verifying feedback, in general (Experiment 1), from an upcoming interaction partner (Experiment 2), and relative to acquaintance-primed participants and favorable feedback (Experiment 3). Finally, self-verification goals were activated, especially for relational self-views deemed high in importance to participants' self-concepts (Experiment 2) and held with high certainty (Experiment 3). Implications for research on self-evaluative goals, the relational self, and the automatic goal activation literature are discussed, as are consequences for close relationships. (PsycINFO Database Record (c) 2009 APA, all rights reserved).

Harbour porpoise distribution can vary at small spatiotemporal scales in energetic habitats

NASA Astrophysics Data System (ADS)

Benjamins, Steven; van Geel, Nienke; Hastie, Gordon; Elliott, Jim; Wilson, Ben

2017-07-01

Marine habitat heterogeneity underpins species distribution and can be generated through interactions between physical and biological drivers at multiple spatiotemporal scales. Passive acoustic monitoring (PAM) is used worldwide to study potential impacts of marine industrial activities on cetaceans, but understanding of animals' site use at small spatiotemporal scales (<1 km, <1 day) remains limited. Small-scale variability in vocalising harbour porpoise (Phocoena phocoena) distribution within two Scottish marine renewable energy development (MRED) sites was investigated by deploying dense arrays of C-POD passive acoustic detectors at a wave energy test site (the European Marine Energy Centre [Billia Croo, Orkney]) and by a minor tidal-stream site (Scarba [Inner Hebrides]). Respective arrays consisted of 7 and 11 moorings containing two C-PODs each and were deployed for up to 55 days. Minimum inter-mooring distances varied between 300-600 m. All C-POD data were analysed at a temporal resolution of whole minutes, with each minute classified as 1 or 0 on the basis of presence/absence of porpoise click trains (Porpoise-Positive Minutes/PPMs). Porpoise detection rates were analysed using Generalised Additive Models (GAMs) with Generalised Estimation Equations (GEEs). Although there were many porpoise detections (wave test site: N=3,432; tidal-stream site: N=17,366), daily detection rates varied significantly within both arrays. Within the wave site array (<1 km diameter), average daily detection rates varied from 4.3 to 14.8 PPMs/day. Within the tidal-stream array (<2 km diameter), average daily detection rates varied from 10.3 to 49.7 PPMs/day. GAM-GEE model results for individual moorings within both arrays indicated linkages between porpoise presence and small-scale heterogeneity among different environmental covariates (e.g., tidal phase, time of day). Porpoise detection rates varied considerably but with coherent patterns between moorings only several hundred

Active Learning with Rationales for Identifying Operationally Significant Anomalies in Aviation

NASA Technical Reports Server (NTRS)

Sharma, Manali; Das, Kamalika; Bilgic, Mustafa; Matthews, Bryan; Nielsen, David Lynn; Oza, Nikunj C.

2016-01-01

A major focus of the commercial aviation community is discovery of unknown safety events in flight operations data. Data-driven unsupervised anomaly detection methods are better at capturing unknown safety events compared to rule-based methods which only look for known violations. However, not all statistical anomalies that are discovered by these unsupervised anomaly detection methods are operationally significant (e.g., represent a safety concern). Subject Matter Experts (SMEs) have to spend significant time reviewing these statistical anomalies individually to identify a few operationally significant ones. In this paper we propose an active learning algorithm that incorporates SME feedback in the form of rationales to build a classifier that can distinguish between uninteresting and operationally significant anomalies. Experimental evaluation on real aviation data shows that our approach improves detection of operationally significant events by as much as 75% compared to the state-of-the-art. The learnt classifier also generalizes well to additional validation data sets.

[Significant increase of glucose transport activity in breast cancer].

PubMed

Li, Juan; Yang, Shou-jing; Zhao, Xi-long; Zhang, Ya-qing; Li, Kai-nan; Cui, Ji-hong; Li, Jing

2008-02-01

To study the expression level and significance of glucose transporter 1 (Glut-1) in normal breast tissue, adenosis, adenoma and breast carcinoma. A total of 147 cases of female breast tissue samples, including 92 cases of invasive ductal carcinoma, 26 cases of breast fibroadenoma, 24 cases of breast adenosis and 5 cases of normal breast tissues, were collected for quantitative detection of the expression of Glut-1 protein by immunohistochemistry (EnVision method) and Western blot, and its mRNA by reverse transcriptase-polymerase chain reaction (RT-PCR). In normal breast tissue and benign lesions of the breast, Glut-1 was undetectable or only weakly detectable in cytoplasm of ductal and acinar epithelia. In contrast, the intensity of Glut-1 staining was significantly higher in invasive ductal carcinomas (P = 0.0002) with protein expression predominantly in cellular membrane and lesser in cytoplasm. Western blot and RT-PCR analyses showed that the expression of Glut-1 protein and mRNA were significantly increased in invasive ductal carcinoma than fibroadenoma (P =0.001 for protein; P <0.05 for mRNA) and adenosis (P =0.001 for protein; P < 0.05 for mRNA). There was a significant difference among groups (P = 0.0002 for protein; P = 0.0001 for mRNA). Glucose transport activity, as indicated by Glut-1 protein and its mRNA expression, significantly increases in breast carcinoma than non-cancerous lesions. The over-expression of Glut-1 in breast carcinoma is tightly coupled with tumor cell proliferation, invasion and metastasis, implying that Glut-1 may serve as a new marker in the early diagnosis and prognostication of breast malignancy as well as a new therapeutic target.

Overweight adult cats have significantly lower voluntary physical activity than adult lean cats.

PubMed

de Godoy, Maria Rc; Shoveller, Anna K

2017-12-01

Objectives The objectives of the current pilot study were to evaluate whether body condition score (BCS) and body weight are significantly related to physical activity counts, and to evaluate potential interaction between BCS and voluntary physical activity measured over a 14 day period. Methods Ten (five lean, five overweight), neutered, adult American Shorthair cats were selected for this study (median age 4 ± 0.5 years). Cats with a BCS of ⩽3.0 were considered lean, whereas cats with a BCS >3.0 were considered overweight, using a 5-point scale. Cats were housed in a free-living environment with indoor/outdoor access and were individually fed once daily a commercially available dry extruded diet and allowed 1 h to eat. Voluntary physical activity was measured consecutively for 14 days using the Actical Activity Monitors that were worn parallel to the ribs and attached via a harness. Results Lean cats had a greater mean total daily voluntary physical activity ( P = 0.0059), and a greater voluntary physical activity during light ( P = 0.0023) and dark ( P = 0.0446) periods, with overweight cats having 60% of the physical activity of lean cats. Lean cats were more active before feeding and during animal care procedures. These data suggest that lean cats have a greater anticipatory physical activity prior to feeding and are more eager to have social interaction with humans than overweight cats. A significant interaction was observed between day of physical activity measurement and BCS for total daily voluntary physical activity ( P = 0.0133) and activity during the light period ( P = 0.0016) where lean cats were consistently more active than overweight cats. In general, cats were more active during weekdays vs weekends. Conclusions and relevance The results of this study suggest that overweight cats are less active than lean cats and that voluntary physical activity level appears to be influenced by social interaction with humans.

FT-Raman study of quinine aqueous solutions with varying pH: 2D correlation study

NASA Astrophysics Data System (ADS)

Wesełucha-Birczyńska, Aleksandra

2007-01-01

Quinine (C 20H 24N 2O 2) is one of the best known, for its antimalarial activity, Cinchona alkaloid. In the current study 2D correlation method was applied to analyze FT-Raman spectra of quinine aqueous solutions with varying pH, which was regarded as an external perturbation. Protonation appears to be the main cause leading to the emergence of cross peaks in the synchronous and asynchronous correlation maps. One should know that protonation process is an important step associated with quinine antimalarial activity. Methoxy group manifests its presence by creation of the respective correlation peaks and seems to be significant for quinine mode of action.

Time-Varying Networks of Inter-Ictal Discharging Reveal Epileptogenic Zone.

PubMed

Zhang, Luyan; Liang, Yi; Li, Fali; Sun, Hongbin; Peng, Wenjing; Du, Peishan; Si, Yajing; Song, Limeng; Yu, Liang; Xu, Peng

2017-01-01

The neuronal synchronous discharging may cause an epileptic seizure. Currently, most of the studies conducted to investigate the mechanism of epilepsy are based on EEGs or functional magnetic resonance imaging (fMRI) recorded during the ictal discharging or the resting-state, and few studies have probed into the dynamic patterns during the inter-ictal discharging that are much easier to record in clinical applications. Here, we propose a time-varying network analysis based on adaptive directed transfer function to uncover the dynamic brain network patterns during the inter-ictal discharging. In addition, an algorithm based on the time-varying outflow of information derived from the network analysis is developed to detect the epileptogenic zone. The analysis performed revealed the time-varying network patterns during different stages of inter-ictal discharging; the epileptogenic zone was activated prior to the discharge onset then worked as the source to propagate the activity to other brain regions. Consistence between the epileptogenic zones detected by our proposed approach and the actual epileptogenic zones proved that time-varying network analysis could not only reveal the underlying neural mechanism of epilepsy, but also function as a useful tool in detecting the epileptogenic zone based on the EEGs in the inter-ictal discharging.

Significant Quantum Effects in Hydrogen Activation

DOE PAGES

Kyriakou, Georgios; Davidson, Erlend R. M.; Peng, Guowen; ...

2014-03-31

Dissociation of molecular hydrogen is an important step in a wide variety of chemical, biological, and physical processes. Due to the light mass of hydrogen, it is recognized that quantum effects are often important to its reactivity. However, understanding how quantum effects impact the reactivity of hydrogen is still in its infancy. Here, we examine this issue using a well-defined Pd/Cu(111) alloy that allows the activation of hydrogen and deuterium molecules to be examined at individual Pd atom surface sites over a wide range of temperatures. Experiments comparing the uptake of hydrogen and deuterium as a function of temperature revealmore » completely different behavior of the two species. The rate of hydrogen activation increases at lower sample temperature, whereas deuterium activation slows as the temperature is lowered. Density functional theory simulations in which quantum nuclear effects are accounted for reveal that tunneling through the dissociation barrier is prevalent for H 2 up to ~190 K and for D 2 up to ~140 K. Kinetic Monte Carlo simulations indicate that the effective barrier to H 2 dissociation is so low that hydrogen uptake on the surface is limited merely by thermodynamics, whereas the D 2 dissociation process is controlled by kinetics. These data illustrate the complexity and inherent quantum nature of this ubiquitous and seemingly simple chemical process. Here, examining these effects in other systems with a similar range of approaches may uncover temperature regimes where quantum effects can be harnessed, yielding greater control of bond-breaking processes at surfaces and uncovering useful chemistries such as selective bond activation or isotope separation.« less

An active principle of Nigella sativa L., thymoquinone, showing significant antimicrobial activity against anaerobic bacteria.

PubMed

Randhawa, Mohammad Akram; Alenazy, Awwad Khalaf; Alrowaili, Majed Gorayan; Basha, Jamith

2017-01-01

Thymoquinone (TQ) is the major active principle of Nigella sativa seed (black seed) and is known to control many fungi, bacteria, and some viruses. However, the activity of TQ against anaerobic bacteria is not well demonstrated. Anaerobic bacteria can cause severe infections, including diarrhea, aspiration pneumonia, and brain abscess, particularly in immunodeficient individuals. The present study aimed to investigate the in vitro antimicrobial activity of TQ against some anaerobic pathogens in comparison to metronidazole. Standard, ATCC, strains of four anaerobic bacteria ( Clostridium difficile , Clostridium perfringens , Bacteroides fragilis , and Bacteroides thetaiotaomicron ), were initially isolated on special Brucella agar base (with hemin and vitamin K). Then, minimum inhibitory concentrations (MICs) of TQ and metronidazole were determined against these anaerobes when grown in Brucella agar, using serial agar dilution method according to the recommended guidelines for anaerobic organisms instructed by the Clinical and Laboratory Standards Institute. TQ showed a significant antimicrobial activity against anaerobic bacteria although much weaker than metronidazole. MICs of TQ and metronidazole against various anaerobic human pathogens tested were found to be between 10-160 mg/L and 0.19-6.25 mg/L, respectively. TQ controlled the anaerobic human pathogenic bacteria, which supports the use of N. sativa in the treatment of diarrhea in folk medicine. Further investigations are in need for determination of the synergistic effect of TQ in combination with metronidazole and the activity of derivatives of TQ against anaerobic infections.

Cobalt-doping-induced synthesis of ceria nanodisks and their significantly enhanced catalytic activity.

PubMed

Guo, Xiao-Hui; Mao, Chao-Chao; Zhang, Ji; Huang, Jun; Wang, Wa-Nv; Deng, Yong-Hui; Wang, Yao-Yu; Cao, Yong; Huang, Wei-Xin; Yu, Shu-Hong

2012-05-21

High-quality cobalt-doped ceria nanostructures with triangular column, triangular slab, and disklike shapes are synthesized by tuning the doping amount of cobalt nitrate in a facile hydrothermal reaction. The cobalt-doped ceria nanodisks display significantly enhanced catalytic activity in CO oxidation due to exposed highly active crystal planes and the presence of numerous surface defects. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

[The significance of extracurricular activities in the life of junior high school students].

PubMed

Sumiya, S; Muto, T

2001-06-01

In this study, the significance of extracurricular activities in the life of junior high school students were examined. Seventh and eighth graders participated in a two-stage questionnaire survey, administered in May and October. Based on developmental stage-environment fit theory (Eccles, Wigfield, & Schiefele, 1998), how well extracurricular activity settings fit needs of the students was analyzed. In support of the theory's hypothesis, results indicated that whether an extracurricular activity satisfied the student's developmental needs affected his/her sense of fulfillment and satisfaction in school life. In addition, the effect of seventh graders' commitment to extracurricular activities on their satisfaction of school life was stronger in October than in May. The findings suggested that for students who felt uneasy in class for whatever reasons, extracurricular activities provided an opportunity for relief.

A Skew-t space-varying regression model for the spectral analysis of resting state brain activity.

PubMed

Ismail, Salimah; Sun, Wenqi; Nathoo, Farouk S; Babul, Arif; Moiseev, Alexader; Beg, Mirza Faisal; Virji-Babul, Naznin

2013-08-01

It is known that in many neurological disorders such as Down syndrome, main brain rhythms shift their frequencies slightly, and characterizing the spatial distribution of these shifts is of interest. This article reports on the development of a Skew-t mixed model for the spatial analysis of resting state brain activity in healthy controls and individuals with Down syndrome. Time series of oscillatory brain activity are recorded using magnetoencephalography, and spectral summaries are examined at multiple sensor locations across the scalp. We focus on the mean frequency of the power spectral density, and use space-varying regression to examine associations with age, gender and Down syndrome across several scalp regions. Spatial smoothing priors are incorporated based on a multivariate Markov random field, and the markedly non-Gaussian nature of the spectral response variable is accommodated by the use of a Skew-t distribution. A range of models representing different assumptions on the association structure and response distribution are examined, and we conduct model selection using the deviance information criterion. (1) Our analysis suggests region-specific differences between healthy controls and individuals with Down syndrome, particularly in the left and right temporal regions, and produces smoothed maps indicating the scalp topography of the estimated differences.

Time-varying value of electric energy efficiency

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mims, Natalie A.; Eckman, Tom; Goldman, Charles

range in value of all the components of avoided costs across the locations studied. -Of the five energy efficiency measures studied, those targeting residential air conditioning in summer-peaking electric systems have the most significant added value when the total time-varying value is considered. -The increased use of rooftop solar systems, storage, and demand response, and the addition of electric vehicles and other major new electricity-consuming end uses are anticipated to significantly alter the load shape of many utility systems in the future. Data used to estimate the impact of energy efficiency measures on electric system peak demands will need to be updated periodically to accurately reflect the value of savings as system load shapes change. -Publicly available components of electric system costs avoided through energy efficiency are not uniform across states and utilities. Inclusion or exclusion of these components and differences in their value affect estimates of the time-varying value of energy efficiency. -Publicly available data on end-use load and energy savings shapes are limited, are concentrated regionally, and should be expanded.« less

Risk Factors for Clinically Significant Intimate Partner Violence among Active-Duty Members

ERIC Educational Resources Information Center

Smith Slep, Amy M.; Foran, Heather M.; Heyman, Richard E.; Snarr, Jeffery D.

2011-01-01

Hypothesized risk factors for men's and women's clinically significant intimate partner violence (CS-IPV) from four ecological levels (i.e., individual, family, workplace, community) were tested in a representative sample of active-duty U.S. Air Force members (N = 42,744). When considered together, we expected only individual and family factors to…

Clinical significance of nailfold capillaroscopy in systemic lupus erythematosus: correlation with endothelial cell activation markers and disease activity.

PubMed

Kuryliszyn-Moskal, A; Ciolkiewicz, M; Klimiuk, P A; Sierakowski, S

2009-01-01

To evaluate whether nailfold capillaroscopy (NC) changes are associated with the main serum endothelial cell activation markers and the disease activity of systemic lupus erythematosus (SLE). Serum levels of vascular endothelial growth factor (VEGF), endothelin-1 (ET-1), soluble E-selectin (sE-selectin), and soluble thrombomodulin (sTM) were determined by an enzyme-linked immunosorbent assay (ELISA) in 80 SLE patients and 33 healthy controls. Nailfold capillary abnormalities were seen in 74 out of 80 (92.5%) SLE patients. A normal capillaroscopic pattern or mild changes were found in 33 (41.25%) and moderate/severe abnormalities in 47 (58.75%) of all SLE patients. In SLE patients a capillaroscopic score >1 was more frequently associated with the presence of internal organ involvement (p < 0.001) as well as with immunosuppressive therapy (p < 0.01). Significant differences were found in VEGF (p < 0.001), ET-1 (p < 0.001), sE-selectin (p < 0.01), and sTM (p < 0.001) serum concentrations between SLE patients with a capillaroscopic score > 1 and controls. SLE patients with severe/moderate capillaroscopic abnormalities showed significantly higher VEGF serum levels than patients with mild changes (p < 0.001). Moreover, there was a significant positive correlation between the severity of capillaroscopic changes and the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) (p < 0.005) as well as between capillaroscopic score and VEGF serum levels (p < 0.001). Our findings confirm the usefulness of NC as a non-invasive technique for the evaluation of microvascular involvement in SLE patients. A relationship between changes in NC, endothelial cell activation markers and clinical features of SLE suggest an important role for microvascular abnormalities in clinical manifestation of the disease.

Subjective Significance Shapes Arousal Effects on Modified Stroop Task Performance: A Duality of Activation Mechanisms Account.

PubMed

Imbir, Kamil K

2016-01-01

Activation mechanisms such as arousal are known to be responsible for slowdown observed in the Emotional Stroop and modified Stroop tasks. Using the duality of mind perspective, we may conclude that both ways of processing information (automatic or controlled) should have their own mechanisms of activation, namely, arousal for an experiential mind, and subjective significance for a rational mind. To investigate the consequences of both, factorial manipulation was prepared. Other factors that influence Stroop task processing such as valence, concreteness, frequency, and word length were controlled. Subjective significance was expected to influence arousal effects. In the first study, the task was to name the color of font for activation charged words. In the second study, activation charged words were, at the same time, combined with an incongruent condition of the classical Stroop task around a fixation point. The task was to indicate the font color for color-meaning words. In both studies, subjective significance was found to shape the arousal impact on performance in terms of the slowdown reduction for words charged with subjective significance.

Varying negative work assistance at the ankle with a soft exosuit during loaded walking.

PubMed

Malcolm, Philippe; Lee, Sangjun; Crea, Simona; Siviy, Christopher; Saucedo, Fabricio; Galiana, Ignacio; Panizzolo, Fausto A; Holt, Kenneth G; Walsh, Conor J

2017-06-26

Only very recently, studies have shown that it is possible to reduce the metabolic rate of unloaded and loaded walking using robotic ankle exoskeletons. Some studies obtained this result by means of high positive work assistance while others combined negative and positive work assistance. There is no consensus about the isolated contribution of negative work assistance. Therefore, the aim of the present study is to examine the effect of varying negative work assistance at the ankle joint while maintaining a fixed level of positive work assistance with a multi-articular soft exosuit. We tested eight participants during walking at 1.5 ms -1 with a 23-kg backpack. Participants wore a version of the exosuit that assisted plantarflexion via Bowden cables tethered to an off-board actuation platform. In four active conditions we provided different rates of exosuit bilateral ankle negative work assistance ranging from 0.015 to 0.037 W kg -1 and a fixed rate of positive work assistance of 0.19 W kg -1 . All active conditions significantly reduced metabolic rate by 11 to 15% compared to a reference condition, where the participants wore the exosuit but no assistance was provided. We found no significant effect of negative work assistance. However, there was a trend (p = .08) toward greater reduction in metabolic rate with increasing negative work assistance, which could be explained by observed reductions in biological ankle and hip joint power and moment. The non-significant trend of increasing negative work assistance with increasing reductions in metabolic rate motivates the value in further studies on the relative effects of negative and positive work assistance. There may be benefit in varying negative work over a greater range or in isolation from positive work assistance.

The cag PAI is intact and functional but HP0521 varies significantly in Helicobacter pylori isolates from Malaysia and Singapore.

PubMed

Schmidt, H-M A; Andres, S; Nilsson, C; Kovach, Z; Kaakoush, N O; Engstrand, L; Goh, K-L; Fock, K M; Forman, D; Mitchell, H

2010-04-01

Helicobacter pylori-related disease is at least partially attributable to the genotype of the infecting strain, particularly the presence of specific virulence factors. We investigated the prevalence of a novel combination of H. pylori virulence factors, including the cag pathogenicity island (PAI), and their association with severe disease in isolates from the three major ethnicities in Malaysia and Singapore, and evaluated whether the cag PAI was intact and functional in vitro. Polymerase chain reaction (PCR) was used to detect dupA, cagA, cagE, cagT, cagL and babA, and to type vacA, the EPIYA motifs, HP0521 alleles and oipA ON status in 159 H. pylori clinical isolates. Twenty-two strains were investigated for IL-8 induction and CagA translocation in vitro. The prevalence of cagA, cagE, cagL, cagT, babA, oipA ON and vacA s1 and i1 was >85%, irrespective of the disease state or ethnicity. The prevalence of dupA and the predominant HP0521 allele and EPIYA motif varied significantly with ethnicity (p < 0.05). A high prevalence of an intact cag PAI was found in all ethnic groups; however, no association was observed between any virulence factor and disease state. The novel association between the HP0521 alleles, EPIYA motifs and host ethnicity indicates that further studies to determine the function of this gene are important.

Cathodic electrochemical activation of Co3O4 nanoarrays: a smart strategy to significantly boost the hydrogen evolution activity.

PubMed

Yang, Li; Zhou, Huang; Qin, Xin; Guo, Xiaodong; Cui, Guanwei; Asiri, Abdullah M; Sun, Xuping

2018-02-22

Co(hydro)oxides show unsatisfactory catalytic activity for the hydrogen evolution reaction (HER) in alkaline media, and it is thus highly desirable but still remains a challenge to design and develop Co(hydro)oxide derived materials as superb hydrogen-evolving catalysts using a facile, rapid and less energy-intensive method. Here, we propose a cathodic electrochemical activation strategy toward greatly boosted HER activity of a Co 3 O 4 nanoarray via room-temperature cathodic polarization in sodium hypophosphite solution. After activation, the overpotential significantly decreases from 260 to 73 mV to drive a geometrical catalytic current density of 10 mA cm -2 in 1.0 M KOH. Notably, this activated electrode also shows strong long-term electrochemical durability with the retention of its catalytic activity at 100 mA cm -2 for at least 40 h.

Impact of varying physical activity levels on airway sensitivity and bronchodilation in healthy humans.

PubMed

Smith, Joshua R; Kurti, Stephanie P; Johnson, Ariel M; Kolmer, Sarah A; Harms, Craig

2015-12-01

The purpose of this study was to determine if the amount of physical activity influences airway sensitivity and bronchodilation in healthy subjects across a range of physical activity levels. Thirty healthy subjects (age, 21.9 ± 2.6 years; 13 men/17 women) with normal pulmonary function reported to the laboratory on 2 separate occasions where they were randomized to breathe either hypertonic saline (HS) (nebulized hypertonic saline (25%) for 20 min) or HS followed by 5 deep inspirations (DIs), which has been reported to bronchodilate the airways. Pulmonary function tests (PFTs) were performed prior to both conditions and following the HS breathing or 5 DIs. Moderate to vigorous physical activity (MVPA) level was measured via accelerometer worn for 7 days. Following the HS breathing, forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) significantly decreased from baseline by -11.8% ± 8.4% and -9.3% ± 6.7%, respectively. A 2-segment linear model determined significant relationships between MVPA and percent change in FEV1 (r = 0.50) and FVC (r = 0.55). MVPA above ∼497 and ∼500 min/week for FEV1 and FVC, respectively, resulted in minor additional improvements (p > 0.05) in PFTs following the HS breathing. Following the DIs, FEV1 and FVC decreased (p < 0.05) by -7.3% ± 8.6% and -5.7% ± 5.7%, respectively, from baseline, but were not related (p > 0.05) to MVPA. In conclusion, these data demonstrate that higher MVPA levels attenuated airway sensitivity but not bronchodilation in healthy subjects.

The Influence of Epoch Length on Physical Activity Patterns Varies by Child's Activity Level

ERIC Educational Resources Information Center

Nettlefold, Lindsay; Naylor, P. J.; Warburton, Darren E. R.; Bredin, Shannon S. D.; Race, Douglas; McKay, Heather A.

2016-01-01

Purpose: Patterns of physical activity (PA) and sedentary time, including volume of bouted activity, are important health indicators. However, the effect of accelerometer epoch length on measurement of these patterns and associations with health outcomes in children remain unknown. Method: We measured activity patterns in 308 children (52% girls,…

Chicken embryo fibroblasts exposed to weak, time-varying magnetic fields share cell proliferation, adenosine deaminase activity, and membrane characteristics of transformed cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parola, A.H.; Porat, N.; Kiesow, L.A.

1993-01-01

Chicken embryo fibroblasts (CEF) exposed to a sinusoidally varying magnetic field (SVMF) (100 Hz, 700 microT, for 24 h) showed a remarkable rise of segmental rotational relaxation rate of adenosine deaminase (ADA, EC 3.5.4.4) as determined by multifrequency phase fluorometry. Pyrene-labeled, small subunit ADA was applied to cultured (normal) CEF, which have available and abundant ADA complexing protein (ADCP) on their plasma membranes. Sine-wave-modulated fluorometry of the pyrene yielded a profile of phase angle vs. modulation frequency. In SVMF-treated cells and in Rous-sarcoma-virus (RSV) transformed cells the differential phase values at low modulation frequencies of the excitation are remarkably reduced.more » This effect is magnetic rather than thermal, because the temperature was carefully controlled and monitored; nevertheless to further check this matter we studied CEF, infected by the RSV-Ts68 temperature-sensitive mutant (36 degrees C transformed, 41 degrees C revertant). When grown at 36 degrees C in the SVMF, cells did not show the slightest trend towards reversion, as would be expected had there been local heating. Concomitant with the increased segmental rotational relaxation rate of ADA, there was a decrease in fluorescence lifetime and a slight, yet significant, increase in membrane lipid microfluidity. These biophysical observations prompted us to examine the effect of SVMF on cell proliferation and ADA activity (a malignancy marker): higher rates of cell proliferation and reduced specific activity of ADA were observed.« less

Specific DNA binding activity of T antigen subclasses varies among different SV40-transformed cell lines.

PubMed

Burger, C; Fanning, E

1983-04-15

Large tumor antigen (T antigen) occurs in at least three different oligomeric subclasses in cells infected or transformed by simian virus 40 (SV40): 5-7 S, 14-16 S, and 23-25 S. The 23-25 S form is complexed with a host phosphoprotein (p53). The DNA binding properties of these three subclasses of T antigen from nine different cell lines and free p53 protein were compared using an immunoprecipitation assay. All three subclasses of T antigen bound specifically to SV40 DNA sequences near the origin of replication. However, the DNA binding activity varied between different cell lines over a 40- to 50-fold range. The 23-25 S and 14-16 S forms from most of the cell lines tested bound much less SV40 origin DNA than 5-7 S T antigen. The free p53 phosphoprotein did not bind specifically to any SV40 DNA sequences.

Varying and unchanging whiteness on the wings of dusk-active and shade-inhabiting Carystoides escalantei butterflies.

PubMed

Ge, Dengteng; Wu, Gaoxiang; Yang, Lili; Kim, Hye-Na; Hallwachs, Winnie; Burns, John M; Janzen, Daniel H; Yang, Shu

2017-07-11

Whiteness, although frequently apparent on the wings, legs, antennae, or bodies of many species of moths and butterflies, along with other colors and shades, has often escaped our attention. Here, we investigate the nanostructure and microstructure of white spots on the wings of Carystoides escalantei , a dusk-active and shade-inhabiting Costa Rican rain forest butterfly (Hesperiidae). On both males and females, two types of whiteness occur: angle dependent (dull or bright) and angle independent, which differ in the microstructure, orientation, and associated properties of their scales. Some spots on the male wings are absent from the female wings. Whether the angle-dependent whiteness is bright or dull depends on the observation directions. The angle-dependent scales also show enhanced retro-reflection. We speculate that the biological functions and evolution of Carystoides spot patterns, scale structures, and their varying whiteness are adaptations to butterfly's low light habitat and to airflow experienced on the wing base vs. wing tip.

Metabonomics-based analysis of Brachyspira pilosicoli's response to tiamulin reveals metabolic activity despite significant growth inhibition.

PubMed

Le Roy, Caroline Ivanne; Passey, Jade Louise; Woodward, Martin John; La Ragione, Roberto Marcello; Claus, Sandrine Paule

2017-06-01

Pathogenic anaerobes Brachyspira spp. are responsible for an increasing number of Intestinal Spirochaetosis (IS) cases in livestock against which few approved treatments are available. Tiamulin is used to treat swine dysentery caused by Brachyspira spp. and recently has been used to handle avian intestinal spirochaetosis (AIS). The therapeutic dose used in chickens requires further evaluation since cases of bacterial resistance to tiamulin have been reported. In this study, we evaluated the impact of tiamulin at varying concentrations on the metabolism of B. pilosicoli using a 1 H-NMR-based metabonomics approach allowing the capture of the overall bacterial metabolic response to antibiotic treatment. Based on growth curve studies, tiamulin impacted bacterial growth even at very low concentration (0.008 μg/mL) although its metabolic activity was barely affected 72 h post exposure to antibiotic treatment. Only the highest dose of tiamulin tested (0.250 μg/mL) caused a major metabolic shift. Results showed that below this concentration, bacteria could maintain a normal metabolic trajectory despite significant growth inhibition by the antibiotic, which may contribute to disease reemergence post antibiotic treatment. Indeed, we confirmed that B. pilosicoli remained viable even after exposition to the highest antibiotic dose. This paper stresses the need to ensure new evaluation of bacterial viability post bacteriostatic exposure such as tiamulin to guarantee treatment efficacy and decrease antibiotic resistance development. Copyright © 2017 Elsevier Ltd. All rights reserved.

Do associations between objectively-assessed physical activity and neighbourhood environment attributes vary by time of the day and day of the week? IPEN adult study.

PubMed

Cerin, Ester; Mitáš, Josef; Cain, Kelli L; Conway, Terry L; Adams, Marc A; Schofield, Grant; Sarmiento, Olga L; Reis, Rodrigo Siqueira; Schipperijn, Jasper; Davey, Rachel; Salvo, Deborah; Orzanco-Garralda, Rosario; Macfarlane, Duncan J; De Bourdeaudhuij, Ilse; Owen, Neville; Sallis, James F; Van Dyck, Delfien

2017-03-20

To more accurately quantify the potential impact of the neighbourhood environment on adults' physical activity (PA), it is important to compare environment-PA associations between periods of the day or week when adults are more versus less likely to be in their neighbourhood and utilise its PA resources. We examined whether, among adults from 10 countries, associations between objectively-assessed neighbourhood environment attributes and moderate-to-vigorous physical activity (MVPA) varied by time of the day and day of the week. The secondary aim was to examine whether such associations varied by employment status, gender and city. This cross-sectional study included 6,712 adults from 14 cities across 10 countries with ≥1 day of valid accelerometer-assessed MVPA and complete information on socio-demographic and objectively-assessed environmental characteristics within 0.5 and 1 km street-network buffers around the home. Accelerometer measures (MVPA min/h) were created for six time periods from early morning until late evening/night, for weekdays and weekend days separately. Associations were estimated using generalized additive mixed models. Time of the day, day of week, gender and employment status were significant moderators of environment-MVPA associations. Land use mix was positively associated with MVPA in women who were employed and in men irrespective of their employment status. The positive associations between MVPA and net residential density, intersection density and land use mix were stronger in the mornings of weekdays and the afternoon/evening periods of both weekdays and weekend days. Associations between number of parks and MVPA were stronger in the mornings and afternoon/evenings irrespective of day of the week. Public transport density showed consistent positive associations with MVPA during weekends, while stronger effects on weekdays were observed in the morning and early evenings. This study suggests that space and time constraints in adults

76 FR 5366 - Agency Information Collection Activities; Proposed Collection; Comment Request; Significant New...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-31

... ENVIRONMENTAL PROTECTION AGENCY [EPA-HQ-OAR-2004-0077; FRL-9259-4] Agency Information Collection Activities; Proposed Collection; Comment Request; Significant New Alternatives Policy (SNAP) Program Final Rulemaking Under Title VI of the Clean Air Act Amendments of 1990; EPA ICR No. 1596.08, OMB Control No. 2060...

Gain-scheduled {{\\mathscr{H}}}_{\\infty } buckling control of a circular beam-column subject to time-varying axial loads

NASA Astrophysics Data System (ADS)

Schaeffner, Maximilian; Platz, Roland

2018-06-01

For slender beam-columns loaded by axial compressive forces, active buckling control provides a possibility to increase the maximum bearable axial load above that of a purely passive structure. In this paper, an approach for gain-scheduled {{\\mathscr{H}}}∞ buckling control of a slender beam-column with circular cross-section subject to time-varying axial loads is investigated experimentally. Piezo-elastic supports with integrated piezoelectric stack actuators at the beam-column ends allow an active stabilization in arbitrary lateral directions. The axial loads on the beam-column influence its lateral dynamic behavior and, eventually, cause the beam-column to buckle. A reduced modal model of the beam-column subject to axial loads including the dynamics of the electrical components is set up and calibrated with experimental data. Particularly, the linear parameter-varying open-loop plant is used to design a model-based gain-scheduled {{\\mathscr{H}}}∞ buckling control that is implemented in an experimental test setup. The beam-column is loaded by ramp- and step-shaped time-varying axial compressive loads that result in a lateral deformation of the beam-column due to imperfections, such as predeformation, eccentric loading or clamping moments. The lateral deformations and the maximum bearable loads of the beam-column are analyzed and compared for the beam-column with and without gain-scheduled {{\\mathscr{H}}}∞ buckling control or, respectively, active and passive configuration. With the proposed gain-scheduled {{\\mathscr{H}}}∞ buckling control it is possible to increase the maximum bearable load of the active beam-column by 19% for ramp-shaped axial loads and to significantly reduce the beam-column deformations for step-shaped axial loads compared to the passive structure.

Oxidants and anti-oxidants status in acne vulgaris patients with varying severity.

PubMed

Al-Shobaili, Hani A

2014-01-01

Acne vulgaris is a common dermatological disorder with a multifactorial pathogenesis. Oxidative status has been implicated in the pathogenesis of several skin diseases, including acne. This study was aimed to investigate the levels of oxidative stress biomarkers in acne vulgaris patients with varying severities. The study involved 156 patients with acne and 46 healthy human controls. Based on clinical examination, patients were grouped into 3 subgroups as follows: mild, moderate, and severe acne. Oxidative stress was examined by measuring plasma levels of catalase (CAT), superoxide dismutase (SOD), total antioxidant capacity (TAC), and malondialdehyde (MDA). Plasma levels of MDA in acne patients were significantly higher as compared with that of the controls, whereas activities of the antioxidant enzymes SOD and CAT were lower. Moreover, TAC was also low in acne patients as compared with that of the controls. Higher MDA levels in the severe acne subgroup as compared with that of the mild and moderate subgroups were also observed. Furthermore, in the severe acne subgroup, a significant negative correlation was observed between MDA and CAT levels. The data suggests that oxidative stress plays a key role in acne progress and may be employed as a biomarker index to assess the disease's activity and to monitor its treatment.

High and varying prices for privately insured patients underscore hospital market power.

PubMed

White, Chapin; Bond, Amelia M; Reschovsky, James D

2013-09-01

Across 13 selected U.S. metropolitan areas, hospital prices for privately insured patients are much higher than Medicare payment rates and vary widely across and within markets, according to a study by the Center for Studying Health System Change (HSC) based on claims data for about 590,000 active and retired nonelderly autoworkers and their dependents. Across the 13 communities, aver­age hospital prices for privately insured patients are about one-and-a-half times Medicare rates for inpatient care and two times what Medicare pays for outpa­tient care. Within individual communities, prices vary widely, with the highest-priced hospital typically paid 60 percent more for inpatient services than the lowest-priced hospital. The price gap within markets is even greater for hospital outpatient care, with the highest-priced hospital typically paid nearly double the lowest-priced hospital. In contrast to the wide variation in hospital prices for pri­vately insured patients across and within markets, prices for primary care physi­cian services generally are close to Medicare rates and vary little within markets. Prices for specialist physician services, however, are higher relative to Medicare and vary more across and within markets. Of the 13 markets, five are in Michigan, which has an unusually concentrated private insurance market, with one insurer commanding a 70-percent market share. Despite the presence of a dominant insurer, almost all Michigan hospi­tals command prices that are higher than Medicare, and some hospitals com­mand prices that are twice what Medicare pays. In the eight markets outside of Michigan, private insurers generally pay even higher hospital prices, with even wider gaps between high- and low-priced hospitals. The variation in hospital and specialist physician prices within communities underscores that some hospitals and physicians have significant market power to command high prices, even in markets with a dominant insurer.

Neural Correlates of Math Gains Vary Depending on Parental Socioeconomic Status (SES)

PubMed Central

Demir-Lira, Özlem Ece; Prado, Jérôme; Booth, James R.

2016-01-01

We used functional magnetic resonance imaging (fMRI) to examine the neural predictors of math development, and asked whether these predictors vary as a function of parental socioeconomic status (SES) in children ranging in age from 8 to 13 years. We independently localized brain regions subserving verbal versus spatial processing in order to characterize relations between activation in these regions during an arithmetic task and long-term change in math skill (up to 3 years). Neural predictors of math gains encompassed brain regions subserving both verbal and spatial processing, but the relation between relative reliance on these regions and math skill growth varied depending on parental SES. Activity in an area of the left inferior frontal gyrus (IFG) identified by the verbal localizer was related to greater growth in math skill at the higher end of the SES continuum, but lesser improvements at the lower end. Activity in an area of the right superior parietal cortex identified by the spatial localizer was related to greater growth in math skill at the lower end of the SES continuum, but lesser improvements at the higher end. Results highlight early neural mechanisms as possible neuromarkers of long-term arithmetic learning and suggest that neural predictors of math gains vary with parental SES. PMID:27378987

Cross-modal pattern of brain activations associated with the processing of self- and significant other's name.

PubMed

Tacikowski, Pawel; Brechmann, André; Nowicka, Anna

2013-09-01

Previous neuroimaging studies have shown that the patterns of brain activity during the processing of personally relevant names (e.g., own name, friend's name, partner's name, etc.) and the names of famous people (e.g., celebrities) are different. However, it is not known how the activity in this network is influenced by the modality of the presented stimuli. In this fMRI study, we investigated the pattern of brain activations during the recognition of aurally and visually presented full names of the subject, a significant other, a famous person and unknown individuals. In both modalities, we found that the processing of self-name and the significant other's name was associated with increased activation in the medial prefrontal cortex (MPFC). Acoustic presentations of these names also activated bilateral inferior frontal gyri (IFG). This pattern of results supports the role of MPFC in the processing of personally relevant information, irrespective of their modality. Copyright © 2012 Wiley Periodicals, Inc., a Wiley company.

Limiting prothrombin activation to meizothrombin is compatible with survival but significantly alters hemostasis in mice

PubMed Central

Shaw, Maureen A.; Kombrinck, Keith W.; McElhinney, Kathryn E.; Sweet, David R.; Flick, Matthew J.; Palumbo, Joseph S.; Cheng, Mei; Esmon, Naomi L.; Esmon, Charles T.; Brill, Alexander; Wagner, Denisa D.; Degen, Jay L.

2016-01-01

Thrombin-mediated proteolysis is central to hemostatic function but also plays a prominent role in multiple disease processes. The proteolytic conversion of fII to α-thrombin (fIIa) by the prothrombinase complex occurs through 2 parallel pathways: (1) the inactive intermediate, prethrombin; or (2) the proteolytically active intermediate, meizothrombin (fIIaMZ). FIIaMZ has distinct catalytic properties relative to fIIa, including diminished fibrinogen cleavage and increased protein C activation. Thus, fII activation may differentially influence hemostasis and disease depending on the pathway of activation. To determine the in vivo physiologic and pathologic consequences of restricting thrombin generation to fIIaMZ, mutations were introduced into the endogenous fII gene, resulting in expression of prothrombin carrying 3 amino acid substitutions (R157A, R268A, and K281A) to limit activation events to yield only fIIaMZ. Homozygous fIIMZ mice are viable, express fII levels comparable with fIIWT mice, and have reproductive success. Although in vitro studies revealed delayed generation of fIIaMZ enzyme activity, platelet aggregation by fIIMZ is similar to fIIWT. Consistent with prior analyses of human fIIaMZ, significant prolongation of clotting times was observed for fIIMZ plasma. Adult fIIMZ animals displayed significantly compromised hemostasis in tail bleeding assays, but did not demonstrate overt bleeding. More notably, fIIMZ mice had 2 significant phenotypic advantages over fIIWT animals: protection from occlusive thrombosis after arterial injury and markedly diminished metastatic potential in a setting of experimental tumor metastasis to the lung. Thus, these novel animals will provide a valuable tool to assess the role of both fIIa and fIIaMZ in vivo. PMID:27252233

Varying electric charge in multiscale spacetimes

NASA Astrophysics Data System (ADS)

Calcagni, Gianluca; Magueijo, João; Fernández, David Rodríguez

2014-01-01

We derive the covariant equations of motion for Maxwell field theory and electrodynamics in multiscale spacetimes with weighted Laplacian. An effective spacetime-dependent electric charge of geometric origin naturally emerges from the theory, thus giving rise to a varying fine-structure constant. The theory is compared with other varying-coupling models, such as those with a varying electric charge or varying speed of light. The theory is also confronted with cosmological observations, which can place constraints on the characteristic scales in the multifractional measure. We note that the model considered here is fundamentally different from those previously proposed in the literature, either of the varying-e or varying-c persuasion.

Nonlinear dynamics near resonances of a rotor-active magnetic bearings system with 16-pole legs and time varying stiffness

NASA Astrophysics Data System (ADS)

Wu, R. Q.; Zhang, W.; Yao, M. H.

2018-02-01

In this paper, we analyze the complicated nonlinear dynamics of rotor-active magnetic bearings (rotor-AMB) with 16-pole legs and the time varying stiffness. The magnetic force with 16-pole legs is obtained by applying the electromagnetic theory. The governing equation of motion for rotor-active magnetic bearings is derived by using the Newton's second law. The resulting dimensionless equation of motion for the rotor-AMB system is expressed as a two-degree-of-freedom nonlinear system including the parametric excitation, quadratic and cubic nonlinearities. The averaged equation of the rotor-AMB system is obtained by using the method of multiple scales when the primary parametric resonance and 1/2 subharmonic resonance are taken into account. From the frequency-response curves, it is found that there exist the phenomena of the soft-spring type nonlinearity and the hardening-spring type nonlinearity in the rotor-AMB system. The effects of different parameters on the nonlinear dynamic behaviors of the rotor-AMB system are investigated. The numerical results indicate that the periodic, quasi-periodic and chaotic motions occur alternately in the rotor-AMB system.

The Regulation of Skeletal Muscle Active Hyperemia: The Differential Role of Adenosine in Muscles of Varied Fiber Types

DTIC Science & Technology

1986-04-21

Role of Adenosine in Muscles of Varied Fiber Types 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER...Role of Adenosine in Muscles of Varied Fiber Types Name of Candidate: Lisa M. Schwartz Doctor of Philosophy Degree Ap r i 1 21 , 1 9 8 6 Thesis and...adenosine in muscles of varied fiber types Lisa M. Schwartz, Doctor of Philosophy, 1986 Dissertation Directed by: Jack E. McKenzie, Associate

Marijuana smoking: effects of varying puff volume and breathhold duration.

PubMed

Azorlosa, J L; Greenwald, M K; Stitzer, M L

1995-02-01

Two studies were conducted to quantify biological and behavioral effects resulting from exposure to controlled doses of marijuana smoke. In one study, puff volume (30, 60 and 90 ml) and in a second study, breathhold duration (0, 10 and 20 sec) were systematically varied while holding constant other smoking topography parameters (number of puffs = 10, interpuff interval = 60 sec and inhalation volume = 25% of vital capacity). Each study also varied levels of delta 9-tetrahydro-cannabinol marijuana cigarette content (1.75% and 3.55%). Regular marijuana users served as subjects (n = 7 in each experiment). Subjects smoked 10 puffs in each of six sessions; a seventh, nonsmoking session (all measures recorded at the same times as in active smoking sessions) served as a control. Variations in puff volume produced significant dose-related changes in postsmoking plasma delta 9-tetrahydro-cannabinol levels, carbon monoxide boost and subjective effects (e.g., "high"). In contrast, breathholding for 10 or 20 sec versus 0 sec increased plasma delta 9-tetrahydro-cannabinol levels but not CO boost or subjective effects. Task performance measures were not reliably influenced by marijuana smoke exposure within the dosing ranges examined. These findings confirm the utility of the controlled smoking technology, support the notion that cumulative puff volume systematically influences biological exposure and subjective effects, but cast doubt on the common belief that prolonged breathholding of marijuana smoke enhances classical subjective effects associated with its reinforcing value in humans.

A significant increase in both basal and maximal calcineurin activity following fluid percussion injury in the rat.

PubMed

Kurz, Jonathan E; Parsons, J Travis; Rana, Aniruddha; Gibson, Cynthia J; Hamm, Robert J; Churn, Severn B

2005-04-01

Calcineurin, a neuronally enriched, calcium-stimulated phosphatase, is an important modulator of many neuronal processes, including several that are physiologically related to the pathology of traumatic brain injury. This study examined the effects of moderate, central fluid percussion injury on the activity of this important neuronal enzyme. Animals were sacrificed at several time-points postinjury and cortical, hippocampal, and cerebellar homogenates were assayed for calcineurin activity by dephosphorylation of p-nitrophenol phosphate. A significant brain injury-dependent increase was observed in both hippocampal and cortical homogenates under both basal and maximally-stimulated reaction conditions. This increase persisted 2-3 weeks post-injury. Brain injury did not alter substrate affinity, but did induce a significant increase in the apparent maximal dephosphorylation rate. Unlike the other brain regions, no change in calcineurin activity was observed in the cerebellum following brain injury. No brain region tested displayed a significant change in calcineurin enzyme levels as determined by Western blot, demonstrating that increased enzyme synthesis was not responsible for the observed increase in activity. The data support the conclusion that fluid percussion injury results in increased calcineurin activity in the rat forebrain. This increased activity has broad physiological implications, possibly resulting in altered cellular excitability or a greater likelihood of neuronal cell death.

A significant increase in both basal and maximal calcineurin activity in the rat pilocarpine model of status epilepticus.

PubMed

Kurz, J E; Sheets, D; Parsons, J T; Rana, A; Delorenzo, R J; Churn, S B

2001-07-01

This study focused on the effects of status epilepticus on the activity of calcineurin, a neuronally enriched, calcium-dependent phosphatase. Calcineurin is an important modulator of many neuronal processes, including learning and memory, induction of apoptosis, receptor function and neuronal excitability. Therefore, a status epilepticus-induced alteration of the activity of this important phosphatase would have significant physiological implications. Status epilepticus was induced by pilocarpine injection and allowed to continue for 60 min. Brain region homogenates were then assayed for calcineurin activity by dephosphorylation of p-nitrophenol phosphate. A significant status epilepticus-dependent increase in both basal and Mn(2+)-dependent calcineurin activity was observed in homogenates isolated from the cortex and hippocampus, but not the cerebellum. This increase was resistant to 150 nM okadaic acid, but sensitive to 50 microM okadaic acid. The increase in basal activity was also resistant to 100 microM sodium orthovanadate. Both maximal dephosphorylation rate and substrate affinity were increased following status epilepticus. However, the increase in calcineurin activity was not found to be due to an increase in calcineurin enzyme levels. Finally, increase in calcineurin activity was found to be NMDA-receptor activation dependent. The data demonstrate that status epilepticus resulted in a significant increase in both basal and maximal calcineurin activity.

Quantification of sound instability in embouchure tremor based on the time-varying fundamental frequency.

PubMed

Lee, André; Voget, Jakob; Furuya, Shinichi; Morise, Masanori; Altenmüller, Eckart

2016-05-01

Task-specific tremor in musicians is an involuntary oscillating muscular activity mostly of the hand or the embouchure, which predominantly occurs while playing the instrument. In contrast to arm or hand tremors, which have been examined and objectified based on movement kinematics and muscular activity, embouchure tremor has not yet been investigated. To quantify and describe embouchure tremor we analysed sound production and investigated the fluctuation of the time-varying fundamental frequency of sustained notes. A comparison between patients with embouchure tremor and healthy controls showed a significantly higher fluctuation of the fundamental frequency for the patients in the high pitch with a tremor frequency range between 3 and 8 Hz. The present findings firstly provide further information about a scarcely described movement disorder and secondly further evaluate a new quantification method for embouchure tremor, which has recently been established for embouchure dystonia.

Mobile Robot Positioning with 433-MHz Wireless Motes with Varying Transmission Powers and a Particle Filter.

PubMed

Canedo-Rodriguez, Adrian; Rodriguez, Jose Manuel; Alvarez-Santos, Victor; Iglesias, Roberto; Regueiro, Carlos V

2015-04-30

In wireless positioning systems, the transmitter's power is usually fixed. In this paper, we explore the use of varying transmission powers to increase the performance of a wireless localization system. To this extent, we have designed a robot positioning system based on wireless motes. Our motes use an inexpensive, low-power sub-1-GHz system-on-chip (CC1110) working in the 433-MHz ISM band. Our localization algorithm is based on a particle filter and infers the robot position by: (1) comparing the power received with the expected one; and (2) integrating the robot displacement. We demonstrate that the use of transmitters that vary their transmission power over time improves the performance of the wireless positioning system significantly, with respect to a system that uses fixed power transmitters. This opens the door for applications where the robot can localize itself actively by requesting the transmitters to change their power in real time.

Mobile Robot Positioning with 433-MHz Wireless Motes with Varying Transmission Powers and a Particle Filter

PubMed Central

Canedo-Rodriguez, Adrian; Rodriguez, Jose Manuel; Alvarez-Santos, Victor; Iglesias, Roberto; Regueiro, Carlos V.

2015-01-01

In wireless positioning systems, the transmitter's power is usually fixed. In this paper, we explore the use of varying transmission powers to increase the performance of a wireless localization system. To this extent, we have designed a robot positioning system based on wireless motes. Our motes use an inexpensive, low-power sub-1-GHz system-on-chip (CC1110) working in the 433-MHz ISM band. Our localization algorithm is based on a particle filter and infers the robot position by: (1) comparing the power received with the expected one; and (2) integrating the robot displacement. We demonstrate that the use of transmitters that vary their transmission power over time improves the performance of the wireless positioning system significantly, with respect to a system that uses fixed power transmitters. This opens the door for applications where the robot can localize itself actively by requesting the transmitters to change their power in real time. PMID:25942641

Identification of Time-Varying Pilot Control Behavior in Multi-Axis Control Tasks

NASA Technical Reports Server (NTRS)

Zaal, Peter M. T.; Sweet, Barbara T.

2012-01-01

Recent developments in fly-by-wire control architectures for rotorcraft have introduced new interest in the identification of time-varying pilot control behavior in multi-axis control tasks. In this paper a maximum likelihood estimation method is used to estimate the parameters of a pilot model with time-dependent sigmoid functions to characterize time-varying human control behavior. An experiment was performed by 9 general aviation pilots who had to perform a simultaneous roll and pitch control task with time-varying aircraft dynamics. In 8 different conditions, the axis containing the time-varying dynamics and the growth factor of the dynamics were varied, allowing for an analysis of the performance of the estimation method when estimating time-dependent parameter functions. In addition, a detailed analysis of pilots adaptation to the time-varying aircraft dynamics in both the roll and pitch axes could be performed. Pilot control behavior in both axes was significantly affected by the time-varying aircraft dynamics in roll and pitch, and by the growth factor. The main effect was found in the axis that contained the time-varying dynamics. However, pilot control behavior also changed over time in the axis not containing the time-varying aircraft dynamics. This indicates that some cross coupling exists in the perception and control processes between the roll and pitch axes.

Surface modification of CoCr alloy using varying concentrations of phosphoric and phosphonoacetic acids: albumin and fibrinogen adsorption, platelet adhesion, activation, and aggregation studies.

PubMed

Thiruppathi, Eagappanath; Larson, Mark K; Mani, Gopinath

2015-01-01

CoCr alloy is commonly used in various cardiovascular medical devices for its excellent physical and mechanical properties. However, the formation of blood clots on the alloy surfaces is a serious concern. This research is focused on the surface modification of CoCr alloy using varying concentrations (1, 25, 50, 75, and 100 mM) of phosphoric acid (PA) and phosphonoacetic acid (PAA) to generate various surfaces with different wettability, chemistry, and roughness. Then, the adsorption of blood plasma proteins such as albumin and fibrinogen and the adhesion, activation, and aggregation of platelets with the various surfaces generated were investigated. Contact angle analysis showed PA and PAA coatings on CoCr provided a gradient of hydrophilic surfaces. FTIR showed PA and PAA were covalently bound to CoCr surface and formed different bonding configurations depending on the concentrations of coating solutions used. AFM showed the formation of homogeneous PA and PAA coatings on CoCr. The single and dual protein adsorption studies showed that the amount of albumin and fibrinogen adsorbed on the alloy surfaces strongly depend on the type of PA and PAA coatings prepared by different concentrations of coating solutions. All PA coated CoCr showed reduced platelet adhesion and activation when compared to control CoCr. Also, 75 and 100 mM PA-CoCr showed reduced platelet aggregation. For PAA coated CoCr, no significant difference in platelet adhesion and activation was observed between PAA coated CoCr and control CoCr. Thus, this study demonstrated that CoCr can be surface modified using PA for potentially reducing the formation of blood clots and improving the blood compatibility of the alloy.

The Significance of Ras Activity in Pancreatic Cancer Initiation

PubMed Central

Logsdon, Craig D.; Lu, Weiqin

2016-01-01

The genetic landscape of pancreatic cancer shows nearly ubiquitous mutations of K-RAS. However, oncogenic K-Rasmt alone is not sufficient to lead to pancreatic ductal adenocarcinoma (PDAC) in either human or in genetically modified adult mouse models. Many stimulants, such as high fat diet, CCK, LPS, PGE2 and others, have physiological effects at low concentrations that are mediated in part through modest increases in K-Ras activity. However, at high concentrations, they induce inflammation that, in the presence of oncogenic K-Ras expression, substantially accelerates PDAC formation. The mechanism involves increased activity of oncogenic K-Rasmt. Unlike what has been proposed in the standard paradigm for the role of Ras in oncogenesis, oncogenic K-Rasmt is now known to not be constitutively active. Rather, it can be activated by standard mechanisms similar to wild-type K-Ras, but its activity is sustained for a prolonged period. Furthermore, if the level of K-Ras activity exceeds a threshold at which it begins to generate its own activators, then a feed-forward loop is formed between K-Ras activity and inflammation and pathological processes including oncogenesis are initiated. Oncogenic K-Rasmt activation, a key event in PDAC initiation and development, is subject to complex regulatory mechanisms. Reagents which inhibit inflammation, such as the Cox2 inhibitor celecoxib, block the feed-forward loop and prevent induction of PDAC in models with endogenous oncogenic K-Rasmt. Increased understanding of the role of activating and inhibitory mechanisms on oncogenic K-Rasmt activity is of paramount importance for the development of preventive and therapeutic strategies to fight against this lethal disease. PMID:26929740

The Significance of Ras Activity in Pancreatic Cancer Initiation.

PubMed

Logsdon, Craig D; Lu, Weiqin

2016-01-01

The genetic landscape of pancreatic cancer shows nearly ubiquitous mutations of K-RAS. However, oncogenic K-Ras(mt) alone is not sufficient to lead to pancreatic ductal adenocarcinoma (PDAC) in either human or in genetically modified adult mouse models. Many stimulants, such as high fat diet, CCK, LPS, PGE2 and others, have physiological effects at low concentrations that are mediated in part through modest increases in K-Ras activity. However, at high concentrations, they induce inflammation that, in the presence of oncogenic K-Ras expression, substantially accelerates PDAC formation. The mechanism involves increased activity of oncogenic K-Ras(mt). Unlike what has been proposed in the standard paradigm for the role of Ras in oncogenesis, oncogenic K-Ras(mt) is now known to not be constitutively active. Rather, it can be activated by standard mechanisms similar to wild-type K-Ras, but its activity is sustained for a prolonged period. Furthermore, if the level of K-Ras activity exceeds a threshold at which it begins to generate its own activators, then a feed-forward loop is formed between K-Ras activity and inflammation and pathological processes including oncogenesis are initiated. Oncogenic K-Ras(mt) activation, a key event in PDAC initiation and development, is subject to complex regulatory mechanisms. Reagents which inhibit inflammation, such as the Cox2 inhibitor celecoxib, block the feed-forward loop and prevent induction of PDAC in models with endogenous oncogenic K-Ras(mt). Increased understanding of the role of activating and inhibitory mechanisms on oncogenic K-Ras(mt) activity is of paramount importance for the development of preventive and therapeutic strategies to fight against this lethal disease.

Identifying typical physical activity on smartphone with varying positions and orientations.

PubMed

Miao, Fen; He, Yi; Liu, Jinlei; Li, Ye; Ayoola, Idowu

2015-04-13

Traditional activity recognition solutions are not widely applicable due to a high cost and inconvenience to use with numerous sensors. This paper aims to automatically recognize physical activity with the help of the built-in sensors of the widespread smartphone without any limitation of firm attachment to the human body. By introducing a method to judge whether the phone is in a pocket, we investigated the data collected from six positions of seven subjects, chose five signals that are insensitive to orientation for activity classification. Decision trees (J48), Naive Bayes and Sequential minimal optimization (SMO) were employed to recognize five activities: static, walking, running, walking upstairs and walking downstairs. The experimental results based on 8,097 activity data demonstrated that the J48 classifier produced the best performance with an average recognition accuracy of 89.6% during the three classifiers, and thus would serve as the optimal online classifier. The utilization of the built-in sensors of the smartphone to recognize typical physical activities without any limitation of firm attachment is feasible.

Holographic cinematography of time-varying reflecting and time-varying phase objects using a Nd:YAG laser.

PubMed

Decker, A J

1982-03-01

The use of a Nd:YAG laser to record holographic motion pictures of time-varying reflecting objects and time-varying phase objects is discussed. Sample frames from both types of holographic motion pictures are presented. The holographic system discussed is intended for three-dimensional flow visualization of the time-varying flows that occur in jet-engine components.

Holographic cinematography of time-varying reflecting and time-varying phase objects using a Nd:YAG laser

NASA Technical Reports Server (NTRS)

Decker, A. J.

1982-01-01

The use of a Nd:YAG laser to record holographic motion pictures of time-varying reflecting objects and time-varying phase objects is discussed. Sample frames from both types of holographic motion pictures are presented. The holographic system discussed is intended for three-dimensional flow visualization of the time-varying flows that occur in jet-engine components.

Time-varying BRDFs.

PubMed

Sun, Bo; Sunkavalli, Kalyan; Ramamoorthi, Ravi; Belhumeur, Peter N; Nayar, Shree K

2007-01-01

The properties of virtually all real-world materials change with time, causing their bidirectional reflectance distribution functions (BRDFs) to be time varying. However, none of the existing BRDF models and databases take time variation into consideration; they represent the appearance of a material at a single time instance. In this paper, we address the acquisition, analysis, modeling, and rendering of a wide range of time-varying BRDFs (TVBRDFs). We have developed an acquisition system that is capable of sampling a material's BRDF at multiple time instances, with each time sample acquired within 36 sec. We have used this acquisition system to measure the BRDFs of a wide range of time-varying phenomena, which include the drying of various types of paints (watercolor, spray, and oil), the drying of wet rough surfaces (cement, plaster, and fabrics), the accumulation of dusts (household and joint compound) on surfaces, and the melting of materials (chocolate). Analytic BRDF functions are fit to these measurements and the model parameters' variations with time are analyzed. Each category exhibits interesting and sometimes nonintuitive parameter trends. These parameter trends are then used to develop analytic TVBRDF models. The analytic TVBRDF models enable us to apply effects such as paint drying and dust accumulation to arbitrary surfaces and novel materials.

Relationship and significance between anti-beta2-glycoprotein I antibodies and platelet activation state in patients with ulcerative colitis.

PubMed

Gao, Yan-Hang; Gao, Pu-Jun; Wang, Chun-Guang; Wang, Xiao-Cong; Piao, Yun-Feng

2008-02-07

To study the relationship between anti-beta2-glycoprotein I (abeta2GPI) antibodies and platelet activation state in patients with ulcerative colitis (UC) and its significance. Peripheral blood samples were collected from 56 UC patients (34 males and 22 females, aged 43.5 years, range 21-66 years), including 36 at active stage and 20 at remission stage, and 25 sex-and age-matched controls. The level of abeta2GPI was measured by ELISA. The platelet activation markers, platelet activation complex-I (PAC-I) and P-selectin (CD62P) were detected by flow cytometry. The A value for IgG abeta2GPI in the active UC group was 0.61 +/- 0.13, significantly higher than that in the remittent UC and control groups (0.50 +/- 0.13 and 0.22 +/- 0.14, P < 0.01). There was a significant difference between the two groups (P < 0.01). The A value for IgM abeta2GPI in the active and remittent UC groups was 0.43 +/- 0.13 and 0.38 +/- 0.12, significantly higher than that in the control group (0.20 +/- 0.12, P < 0.01). However, there was no significant difference between the two groups (P > 0.05). The PAC-I positive rate for the active and remittent UC groups was 30.6% +/- 7.6% and 19.6% +/- 7.8% respectively, significantly higher than that for the control group (6.3% +/- 1.7%, P < 0.01). There was a significant difference between the two groups (P < 0.01). The CD62P positive rate for the active and remittent UC groups was 45.0% +/- 8.8% and 31.9% +/- 7.8% respectively, significantly higher than that for the control group (9.2% +/- 2.7%, P < 0.01). There was a significant difference between the two groups (P < 0.01). In the active UC group, the more severe the state of illness was, the higher the A value for IgG abeta2GPI was, and the positive rate for PAC-I and CD62P was positively correlated with the state of illness (Fabeta2GPI = 3.679, P < 0.05; FPAC-I (%) = 5.346, P < 0.01; and FCD62P (%) = 5. 418, P < 0.01). Meanwhile, in the same state of illness, the A value for IgG abeta2GPI was

Attitudes as Object-Evaluation Associations of Varying Strength

PubMed Central

Fazio, Russell H.

2009-01-01

Historical developments regarding the attitude concept are reviewed, and set the stage for consideration of a theoretical perspective that views attitude, not as a hypothetical construct, but as evaluative knowledge. A model of attitudes as object-evaluation associations of varying strength is summarized, along with research supporting the model’s contention that at least some attitudes are represented in memory and activated automatically upon the individual’s encountering the attitude object. The implications of the theoretical perspective for a number of recent discussions related to the attitude concept are elaborated. Among these issues are the notion of attitudes as “constructions,” the presumed malleability of automatically-activated attitudes, correspondence between implicit and explicit measures of attitude, and postulated dual or multiple attitudes. PMID:19424447

Chronic methamphetamine exposure significantly decreases microglia activation in the arcuate nucleus.

PubMed

Lloyd, Steven A; Corkill, Beau; Bruster, Matthew C; Roberts, Rick L; Shanks, Ryan A

2017-07-01

Methamphetamine is a powerful psychostimulant drug and its use and abuse necessitates a better understanding of its neurobiobehavioral effects. The acute effects of binge dosing of methamphetamine on the neurons in the CNS are well studied. However, the long-term effects of chronic, low-dose methamphetamine are less well characterized, especially in other cell types and areas outside of the major dopamine pathways. Mice were administered 5mg/kg/day methamphetamine for ten days and brain tissue was analyzed using histochemistry and image analysis. Increased microglia activity in the striatum confirmed toxic effects of methamphetamine in this brain region using this dosing paradigm. A significant decrease in microglia activity in the arcuate nucleus of the hypothalamus was observed with no effect noted on dopamine neurons in the arcuate nucleus. Given the importance of this area in homeostatic and neuroendocrine regulation, the current study highlights the need to more fully understand the systemic effects of chronic, low-dose methamphetamine use. The novel finding of microglia downregulation after chronic methamphetamine could lead to advances in understanding neuroinflammatory responses towards addiction treatment and protection from psychostimulant-induced neurotoxicity. Copyright © 2017 Elsevier B.V. All rights reserved.

Batch and column adsorption of herbicide fluroxypyr on different types of activated carbons from water with varied degrees of hardness and alkalinity.

PubMed

Pastrana-Martínez, L M; López-Ramón, M V; Fontecha-Cámara, M A; Moreno-Castilla, C

2010-02-01

There has been little research into the effects of the water hardness and alkalinity of surface waters on the adsorption of herbicides on activated carbons. The aim of this study was to determine the influence of these water characteristics on fluroxypyr adsorption on different activated carbons. At low fluroxypyr surface concentrations, the amount adsorbed from distilled water was related to the surface hydrophobicity. Surface area of carbons covered by fluroxypyr molecules ranged from 60 to 65%. Variations in fluroxypyr solubility with water hardness and alkalinity showed a salting-in effect. Calcium, magnesium and bicarbonate ions were adsorbed to a varied extent on the activated carbons. The presence of fluroxypyr in solution decreased their adsorption due to a competition effect. K(F) from the Freundlich equation linearly increased with water hardness due to salt-screened electrostatic repulsions between charged fluroxypyr molecules. The amount adsorbed from distilled water was largest at high fluroxypyr solution concentrations, because there was no competition between inorganic ions and fluroxypyr molecules. The column breakthrough volume and the amount adsorbed at breakthrough were smaller in tap versus distilled water. Carbon consumption was lower with activated carbon cloth than with the use of granular activated carbon. (c) 2009 Elsevier Ltd. All rights reserved.

Root and Rhizosphere Bacterial Phosphatase Activity Varies with Tree Species and Soil Phosphorus Availability in Puerto Rico Tropical Forest

DOE PAGES

Cabugao, Kristine Grace M.; Timm, Collin M.; Carrell, Alyssa A.; ...

2017-10-30

essential nutrient. Phosphatase activity is one such mechanism that varies in both roots and microbial community members. A thorough understanding of phosphatase activity provides insight into P mineralization in tropical forests, providing not only perspective on ecosystem function of tropical trees and microbial communities, but also in advancing efforts to improve representations of tropical forests in future climates.« less

Root and Rhizosphere Bacterial Phosphatase Activity Varies with Tree Species and Soil Phosphorus Availability in Puerto Rico Tropical Forest

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cabugao, Kristine Grace M.; Timm, Collin M.; Carrell, Alyssa A.

essential nutrient. Phosphatase activity is one such mechanism that varies in both roots and microbial community members. A thorough understanding of phosphatase activity provides insight into P mineralization in tropical forests, providing not only perspective on ecosystem function of tropical trees and microbial communities, but also in advancing efforts to improve representations of tropical forests in future climates.« less

Emotions in freely varying and mono-pitched vowels, acoustic and EGG analyses.

PubMed

Waaramaa, Teija; Palo, Pertti; Kankare, Elina

2015-12-01

Vocal emotions are expressed either by speech or singing. The difference is that in singing the pitch is predetermined while in speech it may vary freely. It was of interest to study whether there were voice quality differences between freely varying and mono-pitched vowels expressed by professional actors. Given their profession, actors have to be able to express emotions both by speech and singing. Electroglottogram and acoustic analyses of emotional utterances embedded in expressions of freely varying vowels [a:], [i:], [u:] (96 samples) and mono-pitched protracted vowels (96 samples) were studied. Contact quotient (CQEGG) was calculated using 35%, 55%, and 80% threshold levels. Three different threshold levels were used in order to evaluate their effects on emotions. Genders were studied separately. The results suggested significant gender differences for CQEGG 80% threshold level. SPL, CQEGG, and F4 were used to convey emotions, but to a lesser degree, when F0 was predetermined. Moreover, females showed fewer significant variations than males. Both genders used more hypofunctional phonation type in mono-pitched utterances than in the expressions with freely varying pitch. The present material warrants further study of the interplay between CQEGG threshold levels and formant frequencies, and listening tests to investigate the perceptual value of the mono-pitched vowels in the communication of emotions.

Systems of meaning and transference: Implicit significant-other activation evokes shared reality.

PubMed

Przybylinski, Elizabeth; Andersen, Susan M

2015-10-01

Evidence shows that representations of significant others (SOs) are used in interpersonal relations-for example, in the social-cognitive process of transference (see Andersen & Chen, 2002), a process that is assumed to serve meaning-making functions (Glassman & Andersen, 1999b). Five studies tested the more specific notion that implicit activation of an SO representation in transference should indirectly activate the worldview shared with the SO, leading to its active pursuit, validation, and protection. Shared worldviews were assessed beforehand, both idiographically, as values (Studies 1 and 4), and nomothetically, as political ideology or religious beliefs (Studies 2, 3, and 5). In each experiment, participants learned about new persons, one subtly resembling their own SO. Transference was assessed (memory bias; positive evaluation; see Andersen, Reznik, & Manzella, 1996) and, crucially, as predicted, when considering the new person resembling their SO (vs. the control persons), participants showed faster response latencies in a lexical decision task to words reflecting the worldview shared with the SO (vs. held only personally, Studies 1-3, or only by the SO, Study 3). With this person, they also anticipated a more meaningful interaction and actively socially tuned to the SO-shared worldview, selecting conversation topics reflecting the SO-shared worldview (vs. personally held or SO-held topics, Studies 1-3). Finally, threatening the SO-shared worldview with this person (vs. threatening personally held, SO-held, or irrelevant worldviews) prompted goal activation to restore the disrupted meaning (Studies 4 and 5), assessed by response latency in a lexical decision task. Transference thus evokes shared meaning systems and serves epistemic functions. (c) 2015 APA, all rights reserved).

Generating survival times to simulate Cox proportional hazards models with time-varying covariates.

PubMed

Austin, Peter C

2012-12-20

Simulations and Monte Carlo methods serve an important role in modern statistical research. They allow for an examination of the performance of statistical procedures in settings in which analytic and mathematical derivations may not be feasible. A key element in any statistical simulation is the existence of an appropriate data-generating process: one must be able to simulate data from a specified statistical model. We describe data-generating processes for the Cox proportional hazards model with time-varying covariates when event times follow an exponential, Weibull, or Gompertz distribution. We consider three types of time-varying covariates: first, a dichotomous time-varying covariate that can change at most once from untreated to treated (e.g., organ transplant); second, a continuous time-varying covariate such as cumulative exposure at a constant dose to radiation or to a pharmaceutical agent used for a chronic condition; third, a dichotomous time-varying covariate with a subject being able to move repeatedly between treatment states (e.g., current compliance or use of a medication). In each setting, we derive closed-form expressions that allow one to simulate survival times so that survival times are related to a vector of fixed or time-invariant covariates and to a single time-varying covariate. We illustrate the utility of our closed-form expressions for simulating event times by using Monte Carlo simulations to estimate the statistical power to detect as statistically significant the effect of different types of binary time-varying covariates. This is compared with the statistical power to detect as statistically significant a binary time-invariant covariate. Copyright © 2012 John Wiley & Sons, Ltd.

Adaptive sliding control of non-autonomous active suspension systems with time-varying loadings

NASA Astrophysics Data System (ADS)

Chen, Po-Chang; Huang, An-Chyau

2005-04-01

An adaptive sliding controller is proposed in this paper for controlling a non-autonomous quarter-car suspension system with time-varying loadings. The bound of the car-body loading is assumed to be available. Then, the reference coordinate is placed at the static position under the nominal loading so that the system dynamic equation is derived. Due to spring nonlinearities, the system property becomes asymmetric after coordinate transformation. Besides, in practical cases, system parameters are not easy to be obtained precisely for controller design. Therefore, in this paper, system uncertainties are lumped into two unknown time-varying functions. Since the variation bound of one of the unknown functions is not available, conventional adaptive schemes and robust designs are not applicable. To deal with this problem, the function approximation technique is employed to represent the unknown function as a finite combination of basis functions. The Lyapunov direct method can thus be used to find adaptive laws for updating coefficients in the approximating series and to prove stability of the closed-loop system. Since the position and velocity measurements of the unsprung mass are lumped into the unknown function, there is no need to install sensors on the axle and wheel assembly in the actual implementation. Simulation results are presented to show the performance of the proposed strategy.

Plant Food Delphinidin-3-Glucoside Significantly Inhibits Platelet Activation and Thrombosis: Novel Protective Roles against Cardiovascular Diseases

PubMed Central

Yang, Yan; Shi, Zhenyin; Reheman, Adili; Jin, Joseph W.; Li, Conglei; Wang, Yiming; Andrews, Marc C.; Chen, Pingguo; Zhu, Guangheng; Ling, Wenhua; Ni, Heyu

2012-01-01

Delphinidin-3-glucoside (Dp-3-g) is one of the predominant bioactive compounds of anthocyanins in many plant foods. Although several anthocyanin compounds have been reported to be protective against cardiovascular diseases (CVDs), the direct effect of anthocyanins on platelets, the key players in atherothrombosis, has not been studied. The roles of Dp-3-g in platelet function are completely unknown. The present study investigated the effects of Dp-3-g on platelet activation and several thrombosis models in vitro and in vivo. We found that Dp-3-g significantly inhibited human and murine platelet aggregation in both platelet-rich plasma and purified platelets. It also markedly reduced thrombus growth in human and murine blood in perfusion chambers at both low and high shear rates. Using intravital microscopy, we observed that Dp-3-g decreased platelet deposition, destabilized thrombi, and prolonged the time required for vessel occlusion. Dp-3-g also significantly inhibited thrombus growth in a carotid artery thrombosis model. To elucidate the mechanisms, we examined platelet activation markers via flow cytometry and found that Dp-3-g significantly inhibited the expression of P-selectin, CD63, CD40L, which reflect platelet α- and δ-granule release, and cytosol protein secretion, respectively. We further demonstrated that Dp-3-g downregulated the expression of active integrin αIIbβ3 on platelets, and attenuated fibrinogen binding to platelets following agonist treatment, without interfering with the direct interaction between fibrinogen and integrin αIIbβ3. We found that Dp-3-g reduced phosphorylation of adenosine monophosphate-activated protein kinase, which may contribute to the observed inhibitory effects on platelet activation. Thus, Dp-3-g significantly inhibits platelet activation and attenuates thrombus growth at both arterial and venous shear stresses, which likely contributes to its protective roles against thrombosis and CVDs. PMID:22624015

Antioxidant activities of polysaccharides from Lentinus edodes and their significance for disease prevention.

PubMed

Chen, Huoliang; Ju, Ying; Li, Junjie; Yu, Min

2012-01-01

The crude polysaccharide (LEP) was extracted by hot water from the fruiting bodies of Lentinus edodes, and further purified by DEAE-cellulose and Sepharose CL-6B chromatography, giving three polysaccharide fractions coded as LEPA1, LEPB1 and LEPC1. In this study, their chemical and physical characteristics of polysaccharide fractions and antioxidant capacities, including scavenging activity against hydroxyl radicals, superoxide radicals and Fe(2+)-chelating ability, were valuated. The results showed that LEPC1 exhibited significantly antioxidant activity at a concentration-dependent manner. Therefore these results indicated that the water-extractable polysaccharide fraction was a potent antioxidant and could be developed to be new health medicine for fighting against various human diseases. Copyright © 2011 Elsevier B.V. All rights reserved.

Treatment of Parkinson's disease could be regulated by movement sensors: subcutaneous infusion of varying apomorphine doses according to the intensity of motor activity.

PubMed

Rodríguez-Molinero, Alejandro; Pérez-Martínez, David A; Català, Andreu; Cabestany, Joan; Yuste, Antonio

2009-04-01

Most recent therapeutic solutions to treat Parkinson's disease seek continuous administration of dopaminergic agonists, as for example rigotine patches or apomorphine infusion pumps. Such drug-delivery devices are aimed at preventing fluctuations in drug plasma levels, which could cause certain symptoms such as wearing-off periods or dyskinesia. However, we postulate that drug plasma levels should not keep constant, but rather adjust to the varying intensity of the different user's activities. The rationale behind this is that the drug amount appropriate to treat a patient at rest is lower than that required to treat the same patient when engaged in physical activity. We propose dynamic real-time dose adjustment, so that the doses increase as the patient starts performing physical activity, thus preventing off periods such as "freeze" phenomenon, and the doses reduce during the resting periods, thus preventing adverse effects. Small portable movement sensors are currently available, which detect the amount and type of activity in a continuous way. Combining such technology with infusion pumps to produce modified pumps capable of adjusting the infusion rate to the user's activity, seems to be feasible in the short-term.

Biomimetic fabrication of pseudohexagonal aragonite tablets through a temperature-varying approach.

PubMed

Liu, Fenglin; Gao, Yanyan; Zhao, Shiqiang; Shen, Qiang; Su, Yunlan; Wang, Dujin

2010-07-07

Pseudohexagonal and single-crystal-like aragonite tablets, found in nacre, could be uniformly fabricated through a temperature-varying approach for the first time, indicating the triplet twinning nature and implying a potential significance in biomineralization.

Significant bone microarchitecture impairment in premenopausal women with active celiac disease.

PubMed

Zanchetta, María Belén; Costa, Florencia; Longobardi, Vanesa; Longarini, Gabriela; Mazure, Roberto Martín; Moreno, María Laura; Vázquez, Horacio; Silveira, Fernando; Niveloni, Sonia; Smecuol, Edgardo; Temprano, María de la Paz; Hwang, Hui Jer; González, Andrea; Mauriño, Eduardo César; Bogado, Cesar; Zanchetta, Jose R; Bai, Julio César

2015-07-01

Patients with active celiac disease (CD) are more likely to have osteoporosis and increased risk of fractures. High-resolution peripheral quantitative computed tomography (HR-pQCT) permits three-dimensional exploration of bone microarchitectural characteristics measuring separately cortical and trabecular compartments, and giving a more profound insight into bone disease pathophysiology and fracture. We aimed to determine the volumetric and microarchitectural characteristics of peripheral bones-distal radius and tibia-in an adult premenopausal cohort with active CD assessed at diagnosis. We prospectively enrolled 31 consecutive premenopausal women with newly diagnosed CD (median age 29 years, range: 18-49) and 22 healthy women of similar age (median age 30 years, range 21-41) and body mass index. Compared with controls, peripheral bones of CD patients were significantly lower in terms of total volumetric density mg/cm(3) (mean ± SD: 274.7 ± 51.7 vs. 324.7 ± 45.8, p 0.0006 at the radius; 264.4 ± 48.7 vs. 307 ± 40.7, p 0.002 at the tibia), trabecular density mg/cm(3) (118.6 ± 31.5 vs. 161.9 ± 33.6, p<0.0001 at the radius; 127.9 ± 28.7 vs. 157.6 ± 15.6, p < 0.0001 at the tibia); bone volume/trabecular volume ratio % (9.9 ± 2.6 vs. 13.5 ± 2.8, p<0.0001 at the radius; 10.6 ± 2.4 vs. 13.1 ± 1.3, p < 0.0001 at the tibia); number of trabeculae 1/mm (1.69 ± 0.27 vs. 1.89 ± 0.26, p 0.009 at the radius; 1.53 ± 0.32 vs. 1.80 ± 0.26, p 0.002 at the tibia); and trabecular thickness mm (0.058 ± 0.010 vs. 0.071 ± 0.008, p < 0.0001 at the radius with no significant difference at the tibia). Cortical density was significantly lower in both regions (D comp mg/cm(3) 860 ± 57.2 vs. 893.9 ± 43, p 0.02; 902.7 ± 48.7 vs. 932.6 ± 32.6, p 0.01 in radius and tibia respectively). Although cortical thickness was lower in CD patients, it failed to show any significant inter-group difference (a-8% decay with p 0.11 in both bones). Patients with symptomatic CD (n = 22) had

Significance of activity peaks in fruit flies, Drosophila melanogaster, under seminatural conditions.

PubMed

De, Joydeep; Varma, Vishwanath; Saha, Soham; Sheeba, Vasu; Sharma, Vijay Kumar

2013-05-28

Studies on circadian entrainment have traditionally been performed under controlled laboratory conditions. Although these studies have served the purpose of providing a broad framework for our understanding of regulation of rhythmic behaviors under cyclic conditions, they do not reveal how organisms keep time in nature. Although a few recent studies have attempted to address this, it is not yet clear which environmental factors regulate rhythmic behaviors in nature and how. Here, we report the results of our studies aimed at examining (i) whether and how changes in natural light affect activity/rest rhythm and (ii) what the functional significance of this rhythmic behavior might be. We found that wild-type strains of fruit flies, Drosophila melanogaster, display morning (M), afternoon (A), and evening (E) peaks of activity under seminatural conditions (SN), whereas under constant darkness in otherwise SN, they exhibited M and E peaks, and under constant light in SN, only the E peak occurred. Unlike the A peak, which requires exposure to bright light in the afternoon, light information is dispensable for the M and E peaks. Visual examination of behaviors suggests that the M peak is associated with courtship-related locomotor activity and the A peak is due to an artifact of the experimental protocol and largely circadian clock independent.

Administrative database code accuracy did not vary notably with changes in disease prevalence.

PubMed

van Walraven, Carl; English, Shane; Austin, Peter C

2016-11-01

Previous mathematical analyses of diagnostic tests based on the categorization of a continuous measure have found that test sensitivity and specificity varies significantly by disease prevalence. This study determined if the accuracy of diagnostic codes varied by disease prevalence. We used data from two previous studies in which the true status of renal disease and primary subarachnoid hemorrhage, respectively, had been determined. In multiple stratified random samples from the two previous studies having varying disease prevalence, we measured the accuracy of diagnostic codes for each disease using sensitivity, specificity, and positive and negative predictive value. Diagnostic code sensitivity and specificity did not change notably within clinically sensible disease prevalence. In contrast, positive and negative predictive values changed significantly with disease prevalence. Disease prevalence had no important influence on the sensitivity and specificity of diagnostic codes in administrative databases. Copyright © 2016 Elsevier Inc. All rights reserved.

Modeling information diffusion in time-varying community networks

NASA Astrophysics Data System (ADS)

Cui, Xuelian; Zhao, Narisa

2017-12-01

Social networks are rarely static, and they typically have time-varying network topologies. A great number of studies have modeled temporal networks and explored social contagion processes within these models; however, few of these studies have considered community structure variations. In this paper, we present a study of how the time-varying property of a modular structure influences the information dissemination. First, we propose a continuous-time Markov model of information diffusion where two parameters, mobility rate and community attractiveness, are introduced to address the time-varying nature of the community structure. The basic reproduction number is derived, and the accuracy of this model is evaluated by comparing the simulation and theoretical results. Furthermore, numerical results illustrate that generally both the mobility rate and community attractiveness significantly promote the information diffusion process, especially in the initial outbreak stage. Moreover, the strength of this promotion effect is much stronger when the modularity is higher. Counterintuitively, it is found that when all communities have the same attractiveness, social mobility no longer accelerates the diffusion process. In addition, we show that the local spreading in the advantage group has been greatly enhanced due to the agglomeration effect caused by the social mobility and community attractiveness difference, which thus increases the global spreading.

Relationship and significance between anti-β2-glycoproteinI antibodies and platelet activation state in patients with ulcerative colitis

PubMed Central

Gao, Yan-Hang; Gao, Pu-Jun; Wang, Chun-Guang; Wang, Xiao-Cong; Piao, Yun-Feng

2008-01-01

AIM: To study the relationship between anti-β2-glycoprotein I (aβ2GPI) antibodies and platelet activation state in patients with ulcerative colitis (UC) and its significance. METHODS: Peripheral blood samples were collected from 56 UC patients (34 males and 22 females, aged 43.5 years, range 21-66 years), including 36 at active stage and 20 at remission stage, and 25 sex-and age-matched controls. The level of aβ2GPI was measured by ELISA. The platelet activation markers, platelet activation complex-I (PAC-I) and P-selectin (CD62P) were detected by flow cytometry. RESULTS: The A value for IgG aβ2GPI in the active UC group was 0.61 ± 0.13, significantly higher than that in the remittent UC and control groups (0.50 ± 0.13 and 0.22 ± 0.14, P < 0.01). There was a significant difference between the two groups (P < 0.01). The A value for IgM aβ2GPI in the active and remittent UC groups was 0.43 ± 0.13 and 0.38 ± 0.12, significantly higher than that in the control group (0.20 ± 0.12, P < 0.01). However, there was no significant difference between the two groups (P > 0.05). The PAC-I positive rate for the active and remittent UC groups was 30.6% ± 7.6% and 19.6% ± 7.8% respectively, significantly higher than that for the control group (6.3% ± 1.7%, P < 0.01). There was a significant difference between the two groups (P < 0.01). The CD62P positive rate for the active and remittent UC groups was 45.0% ± 8.8% and 31.9% ± 7.8% respectively, significantly higher than that for the control group (9.2% ± 2.7%, P < 0.01). There was a significant difference between the two groups (P < 0.01). In the active UC group, the more severe the state of illness was, the higher the A value for IgG aβ2GPI was, and the positive rate for PAC-I and CD62P was positively correlated with the state of illness (Faβ2GPI = 3.679, P < 0.05; FPAC-I (%) = 5.346, P < 0.01; and FCD62P (%) = 5. 418, P < 0.01). Meanwhile, in the same state of illness, the A value for IgG aβ2GPI was positively

Groundwater Ecosystems Vary with Land Use across a Mixed Agricultural Landscape.

PubMed

Korbel, K L; Hancock, P J; Serov, P; Lim, R P; Hose, G C

2013-01-01

Changes in surface land use may threaten groundwater quality and ecosystem integrity, particularly in shallow aquifers where links between groundwater and surface activities are most intimate. In this study we examine the response of groundwater ecosystem to agricultural land uses in the shallow alluvial aquifer of the Gwydir River valley, New South Wales, Australia. We compared groundwater quality and microbial and stygofauna assemblages among sites under irrigated cropping, non-irrigated cropping and grazing land uses. Stygofauna abundance and richness was greatest at irrigated sites, with the composition of the assemblage suggestive of disturbance. Microbial assemblages and water quality also varied with land use. Our study demonstrates significant differences in the composition of groundwater ecosystems in areas with different surface land use, and highlights the utility of groundwater biota for biomonitoring, particularly in agricultural landscapes. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Identification of the active compounds and significant pathways of yinchenhao decoction based on network pharmacology

PubMed Central

Huang, Jihan; Cheung, Fan; Tan, Hor-Yue; Hong, Ming; Wang, Ning; Yang, Juan; Feng, Yibin; Zheng, Qingshan

2017-01-01

Yinchenhao decoction (YCHD) is a traditional Chinese medicine formulation, which has been widely used for the treatment of jaundice for 2,000 years. Currently, YCHD is used to treat various liver disorders and metabolic diseases, however its chemical/pharmacologic profiles remain to be elucidated. The present study identified the active compounds and significant pathways of YCHD based on network pharmacology. All of the chemical ingredients of YCHD were retrieved from the Traditional Chinese Medicine Systems Pharmacology database. Absorption, distribution, metabolism and excretion screening with oral bioavailability (OB) screening, drug-likeness (DL) and intestinal epithelial permeability (Caco-2) evaluation were applied to discover the bioactive compounds in YCHD. Following this, target prediction, pathway identification and network construction were employed to clarify the mechanism of action of YCHD. Following OB screening, and evaluation of DL and Caco-2, 34 compounds in YCHD were identified as potential active ingredients, of which 30 compounds were associated with 217 protein targets. A total of 31 significant pathways were obtained by performing enrichment analyses of 217 proteins using the JEPETTO 3.x plugin, and 16 classes of gene-associated diseases were revealed by performing enrichment analyses using Database for Annotation, Visualization and Integrated Discovery v6.7. The present study identified potential active compounds and significant pathways in YCHD. In addition, the mechanism of action of YCHD in the treatment of various diseases through multiple pathways was clarified. PMID:28791364

Proteomic analysis of soybean root exposed to varying sizes of silver nanoparticles under flooding stress.

PubMed

Mustafa, Ghazala; Sakata, Katsumi; Komatsu, Setsuko

2016-10-04

Silver nanoparticles (Ag-NPs) are excessively used as antibacterial agents; however, environmental interaction specifically with the plants remain uncertain. To study the size-dependent effects of Ag-NPs on soybean under flooding, a proteomic technique was used. Morphological analysis revealed that treatment with Ag-NPs of 15nm promoted soybean growth under flooding compared to 2 and 50-80nm. A total of 228 common proteins that significantly changed in abundance under flooding without and with Ag-NPs of 2, 15, and 50-80nm. Under varying sizes of Ag-NPs, number of protein synthesis related proteins decreased compared to flooding while number of amino acid synthesis related proteins were increased under Ag-NPs of 15nm. Hierarchical clustering identified the ribosomal proteins that increased under Ag-NPs of 15nm while decreased under other sizes. In silico protein-protein interaction indicated the beta ketoacyl reducatse 1 as the most interacted protein under Ag-NPs of 15nm while least interacted under other sizes. The beta ketoacyl reductase 1 was up-regulated under Ag-NPs of 15nm while its enzyme activity was decreased. These results suggest that the different sizes of Ag-NPs might affect the soybean growth under flooding by regulating the proteins related to amino acid synthesis and wax formation. This study highlighted the response of soybean proteins towards varying sizes of Ag NPs under flooding stress using gel-free proteomic technique. The Ag NPs of 15nm improved the length of root including hypocotyl of soybean. The proteins related to protein metabolism, cell division/organization, and amino acid metabolism were differentially changed under the varying sizes of Ag NPs. The protein synthesis-related proteins were decreased while amino acid metabolism-related proteins were increased under varying sizes of Ag NPs. The ribosomal proteins were increased under Ag NPs of 15nm. The beta ketoacyl reductase 1 was identified as the most interacted protein under varying

Germination niche breadth varies inconsistently among three Asclepias congeners along a latitudinal gradient.

PubMed

Finch, Jessamine; Walck, Jeffrey L; Hidayati, Siti N; Kramer, Andrea T; Lason, Victoria; Havens, Kayri

2018-05-20

Species responses to climate change will be primarily driven by their environmental tolerance range, or niche breadth, with the expectation that broad niches will increase resilience. Niche breadth is expected to be greater in more heterogeneous environments and moderated by life history. Niche breadth also varies across life stage. Therefore, the life stage with the narrowest niche may serve as the best predictor of climatic vulnerability. To investigate the relationship between niche breadth, climate, and life stage we identify germination niche breadth for dormant and nondormant seeds in multiple populations of three milkweed (Asclepias) species. Complementary trials evaluated germination under conditions simulating historic and predicted future climate by varying cold-moist stratification temperature, length, and incubation temperature. Germination niche breadth was derived from germination evenness across treatments (Levins B n ), with stratified seeds considered less dormant than non-stratified seeds. Germination response varies significantly among species, populations, and treatments. Cold-moist stratification ≥ 4 weeks (1-3°C) followed by incubation at 25/15°C+ achieves peak germination for most populations. Germination niche breadth significantly expands following stratification and interacts significantly with latitude of origin. Interestingly, two species display a positive relationship between niche breadth and latitude, while the third presents a concave quadratic relationship. Germination niche breadth significantly varies by species, latitude, and population, suggesting an interaction between source climate, life history, and site-specific factors. Results contribute to our understanding of inter- and intraspecific variation in germination, underscore the role of dormancy in germination niche breadth, and have implications for prioritizing and conserving species under climate change. This article is protected by copyright. All rights reserved

Emotion regulation ability varies in relation to intrinsic functional brain architecture

PubMed Central

Uchida, Mai; Biederman, Joseph; Gabrieli, John D. E.; Micco, Jamie; de Los Angeles, Carlo; Brown, Ariel; Kenworthy, Tara; Kagan, Elana

2015-01-01

This study investigated the neural basis of individual variation in emotion regulation, specifically the ability to reappraise negative stimuli so as to down-regulate negative affect. Brain functions in young adults were measured with functional Magnetic Resonance Imaging during three conditions: (i) attending to neutral pictures; (ii) attending to negative pictures and (iii) reappraising negative pictures. Resting-state functional connectivity was measured with amygdala and dorsolateral prefrontal cortical (DLPFC) seed regions frequently associated with emotion regulation. Participants reported more negative affect after attending to negative than neutral pictures, and less negative affect following reappraisal. Both attending to negative vs neutral pictures and reappraising vs attending to negative pictures yielded widespread activations that were significantly right-lateralized for attending to negative pictures and left-lateralized for reappraising negative pictures. Across participants, more successful reappraisal correlated with less trait anxiety and more positive daily emotion, greater activation in medial and lateral prefrontal regions, and lesser resting-state functional connectivity between (a) right amygdala and both medial prefrontal and posterior cingulate cortices, and (b) bilateral DLPFC and posterior visual cortices. The ability to regulate emotion, a source of resilience or of risk for distress, appears to vary in relation to differences in intrinsic functional brain architecture. PMID:25999363

From calls to communities: a model for time-varying social networks

NASA Astrophysics Data System (ADS)

Laurent, Guillaume; Saramäki, Jari; Karsai, Márton

2015-11-01

Social interactions vary in time and appear to be driven by intrinsic mechanisms that shape the emergent structure of social networks. Large-scale empirical observations of social interaction structure have become possible only recently, and modelling their dynamics is an actual challenge. Here we propose a temporal network model which builds on the framework of activity-driven time-varying networks with memory. The model integrates key mechanisms that drive the formation of social ties - social reinforcement, focal closure and cyclic closure, which have been shown to give rise to community structure and small-world connectedness in social networks. We compare the proposed model with a real-world time-varying network of mobile phone communication, and show that they share several characteristics from heterogeneous degrees and weights to rich community structure. Further, the strong and weak ties that emerge from the model follow similar weight-topology correlations as real-world social networks, including the role of weak ties.

Detectability of bovine TB using the tuberculin skin test does not vary significantly according to pathogen genotype within Northern Ireland.

PubMed

Wright, David M; Allen, Adrian R; Mallon, Thomas R; McDowell, Stanley W J; Bishop, Stephen C; Glass, Elizabeth J; Bermingham, Mairead L; Woolliams, John A; Skuce, Robin A

2013-10-01

Strains of many infectious diseases differ in parameters that influence epidemic spread, for example virulence, transmissibility, detectability and host specificity. Knowledge of inter-strain variation can be exploited to improve management and decrease disease incidence. Bovine tuberculosis (bTB) is increasingly prevalent among farmed cattle in the UK, exerting a heavy economic burden on the farming industry and government. We aimed to determine whether strains of Mycobacterium bovis (the causative agent of bTB) identified and classified using genetic markers (spoligotyping and multi-locus VNTR analysis) varied in response to the tuberculin skin test; this being the primary method of bTB detection used in the UK. Inter-strain variation in detectability of M. bovis could have important implications for disease control. The skin test is based on a differential delayed type hypersensitivity (DTH) response to intradermal injections of purified protein derivative (PPD) from M. bovis (PPD-B) and Mycobacterium avium (PPD-A). We searched for an association between skin test response (PPD-B skin rise minus PPD-A skin rise) and M. bovis genotype at the disclosing test in culture-confirmed cases using a field dataset consisting of 21,000 isolates belonging to 63 genotypes of M. bovis from cattle in Northern Ireland. We found no substantial variation among genotypes (estimated responses clustered tightly around the mean) controlling for animal sex, breed and test effects. We also estimated the ratio of skin test detected to undetected cases (i.e. cases only detected at abattoir). The skin test detection ratio varied among abattoirs with some detecting a greater proportion of cases than others but this variation was unrelated to the community composition of genotypes within each abattoir catchment. These two lines of evidence indicate that M. bovis genotypes in Northern Ireland have similar detectability using the skin test. Crown Copyright © 2013. Published by Elsevier B

A New Time-varying Concept of Risk in a Changing Climate.

PubMed

Sarhadi, Ali; Ausín, María Concepción; Wiper, Michael P

2016-10-20

In a changing climate arising from anthropogenic global warming, the nature of extreme climatic events is changing over time. Existing analytical stationary-based risk methods, however, assume multi-dimensional extreme climate phenomena will not significantly vary over time. To strengthen the reliability of infrastructure designs and the management of water systems in the changing environment, multidimensional stationary risk studies should be replaced with a new adaptive perspective. The results of a comparison indicate that current multi-dimensional stationary risk frameworks are no longer applicable to projecting the changing behaviour of multi-dimensional extreme climate processes. Using static stationary-based multivariate risk methods may lead to undesirable consequences in designing water system infrastructures. The static stationary concept should be replaced with a flexible multi-dimensional time-varying risk framework. The present study introduces a new multi-dimensional time-varying risk concept to be incorporated in updating infrastructure design strategies under changing environments arising from human-induced climate change. The proposed generalized time-varying risk concept can be applied for all stochastic multi-dimensional systems that are under the influence of changing environments.

Clinical significance of fibromyalgia syndrome in different rheumatic diseases: Relation to disease activity and quality of life.

PubMed

El-Rabbat M, Sarah; Mahmoud, Nermeen K; Gheita, Tamer A

2017-04-11

To describe the frequencies of fibromyalgia syndrome (FMS) in various rheumatic diseases; rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), systemic sclerosis (SSc) and Behçets disease (BD) patients and to study the relation to clinical manifestations and quality of life (QoL). 160 patients (50 RA, 50 SLE, 30 SSc and 30 BD) and matched corresponding healthy controls were included. Disease activity was assessed using disease activity score in 28 joints (DAS28) for RA, SLE Disease Activity index (SLEDAI), modified Rodnan skin score for SSc and BD Current Activity Form (BDCAF). The QoL was also recorded. Severity in FMS cases was estimated using the revised Fibromyalgia Impact Questionnaire score. In the RA, SLE, SSc and BD patients, FMS was found in 14%, 18%, 6.67% and 3.33% respectively compared to 2.1%, 3%, 3.3% and 0% in their corresponding controls. In RA patients, DAS28 was significantly higher in those with FMS (p=0.009) and significantly correlated with both Widespread Pain Index (WPI) (p=0.011) and Symptom Severity (SS) scale (p=0.012). The QoL scale in those with FMS was significantly worse (62.3±7.9) compared to those without (71.7±14.4) (p=0.023). In SLE patients, The WPI and SS both significantly correlated with the presence of thrombosis (r=0.28, p=0.049 and r=0.43, p=0.002 respectively). The SS scale tended to correlate with the SLEDAI (r=0.28, p=0.05). In BD patients, BDCAF and WPI significantly correlated (p=0.03). Fibromyalgia syndrome is more frequent in rheumatic diseases, could be related to the disease activity in RA and BD patients and to thrombosis in SLE and affected the QoL in RA. Copyright © 2017 Elsevier España, S.L.U. and Sociedad Española de Reumatología y Colegio Mexicano de Reumatología. All rights reserved.

Coexistence and local μ-stability of multiple equilibrium points for memristive neural networks with nonmonotonic piecewise linear activation functions and unbounded time-varying delays.

PubMed

Nie, Xiaobing; Zheng, Wei Xing; Cao, Jinde

2016-12-01

In this paper, the coexistence and dynamical behaviors of multiple equilibrium points are discussed for a class of memristive neural networks (MNNs) with unbounded time-varying delays and nonmonotonic piecewise linear activation functions. By means of the fixed point theorem, nonsmooth analysis theory and rigorous mathematical analysis, it is proven that under some conditions, such n-neuron MNNs can have 5 n equilibrium points located in ℜ n , and 3 n of them are locally μ-stable. As a direct application, some criteria are also obtained on the multiple exponential stability, multiple power stability, multiple log-stability and multiple log-log-stability. All these results reveal that the addressed neural networks with activation functions introduced in this paper can generate greater storage capacity than the ones with Mexican-hat-type activation function. Numerical simulations are presented to substantiate the theoretical results. Copyright © 2016 Elsevier Ltd. All rights reserved.

Physiological Signal Analysis for Evaluating Flow during Playing of Computer Games of Varying Difficulty.

PubMed

Tian, Yu; Bian, Yulong; Han, Piguo; Wang, Peng; Gao, Fengqiang; Chen, Yingmin

2017-01-01

Flow is the experience of effortless attention, reduced self-consciousness, and a deep sense of control that typically occurs during the optimal performance of challenging tasks. On the basis of the person-artifact-task model, we selected computer games (tasks) with varying levels of difficulty (difficult, medium, and easy) and shyness (personality) as flow precursors to study the physiological activity of users in a flow state. Cardiac and respiratory activity and mean changes in skin conductance (SC) were measured continuously while the participants ( n = 40) played the games. Moreover, the associations between self-reported psychological flow and physiological measures were investigated through a series of repeated-measures analyses. The results showed that the flow experience is related to a faster respiratory rate, deeper respiration, moderate heart rate (HR), moderate HR variability, and moderate SC. The main effect of shyness was non-significant, whereas the interaction of shyness and difficulty influenced the flow experience. These findings are discussed in relation to current models of arousal and valence. The results indicate that the flow state is a state of moderate mental effort that arises through the increased parasympathetic modulation of sympathetic activity.

Physiological Signal Analysis for Evaluating Flow during Playing of Computer Games of Varying Difficulty

PubMed Central

Tian, Yu; Bian, Yulong; Han, Piguo; Wang, Peng; Gao, Fengqiang; Chen, Yingmin

2017-01-01

Flow is the experience of effortless attention, reduced self-consciousness, and a deep sense of control that typically occurs during the optimal performance of challenging tasks. On the basis of the person–artifact–task model, we selected computer games (tasks) with varying levels of difficulty (difficult, medium, and easy) and shyness (personality) as flow precursors to study the physiological activity of users in a flow state. Cardiac and respiratory activity and mean changes in skin conductance (SC) were measured continuously while the participants (n = 40) played the games. Moreover, the associations between self-reported psychological flow and physiological measures were investigated through a series of repeated-measures analyses. The results showed that the flow experience is related to a faster respiratory rate, deeper respiration, moderate heart rate (HR), moderate HR variability, and moderate SC. The main effect of shyness was non-significant, whereas the interaction of shyness and difficulty influenced the flow experience. These findings are discussed in relation to current models of arousal and valence. The results indicate that the flow state is a state of moderate mental effort that arises through the increased parasympathetic modulation of sympathetic activity. PMID:28725206

Trends in space activities in 2014: The significance of the space activities of governments

NASA Astrophysics Data System (ADS)

Paikowsky, Deganit; Baram, Gil; Ben-Israel, Isaac

2016-01-01

This article addresses the principal events of 2014 in the field of space activities, and extrapolates from them the primary trends that can be identified in governmental space activities. In 2014, global space activities centered on two vectors. The first was geopolitical, and the second relates to the matrix between increasing commercial space activities and traditional governmental space activities. In light of these two vectors, the article outlines and analyzes trends of space exploration, human spaceflights, industry and technology, cooperation versus self-reliance, and space security and sustainability. It also reviews the space activities of the leading space-faring nations.

Neural coding of time-varying interaural time differences and time-varying amplitude in the inferior colliculus

PubMed Central

2017-01-01

Binaural cues occurring in natural environments are frequently time varying, either from the motion of a sound source or through interactions between the cues produced by multiple sources. Yet, a broad understanding of how the auditory system processes dynamic binaural cues is still lacking. In the current study, we directly compared neural responses in the inferior colliculus (IC) of unanesthetized rabbits to broadband noise with time-varying interaural time differences (ITD) with responses to noise with sinusoidal amplitude modulation (SAM) over a wide range of modulation frequencies. On the basis of prior research, we hypothesized that the IC, one of the first stages to exhibit tuning of firing rate to modulation frequency, might use a common mechanism to encode time-varying information in general. Instead, we found weaker temporal coding for dynamic ITD compared with amplitude modulation and stronger effects of adaptation for amplitude modulation. The differences in temporal coding of dynamic ITD compared with SAM at the single-neuron level could be a neural correlate of “binaural sluggishness,” the inability to perceive fluctuations in time-varying binaural cues at high modulation frequencies, for which a physiological explanation has so far remained elusive. At ITD-variation frequencies of 64 Hz and above, where a temporal code was less effective, noise with a dynamic ITD could still be distinguished from noise with a constant ITD through differences in average firing rate in many neurons, suggesting a frequency-dependent tradeoff between rate and temporal coding of time-varying binaural information. NEW & NOTEWORTHY Humans use time-varying binaural cues to parse auditory scenes comprising multiple sound sources and reverberation. However, the neural mechanisms for doing so are poorly understood. Our results demonstrate a potential neural correlate for the reduced detectability of fluctuations in time-varying binaural information at high speeds, as occurs

Vesicle biomechanics in a time-varying magnetic field.

PubMed

Ye, Hui; Curcuru, Austen

2015-01-01

Cells exhibit distortion when exposed to a strong electric field, suggesting that the field imposes control over cellular biomechanics. Closed pure lipid bilayer membranes (vesicles) have been widely used for the experimental and theoretical studies of cellular biomechanics under this electrodeformation. An alternative method used to generate an electric field is by electromagnetic induction with a time-varying magnetic field. References reporting the magnetic control of cellular mechanics have recently emerged. However, theoretical analysis of the cellular mechanics under a time-varying magnetic field is inadequate. We developed an analytical theory to investigate the biomechanics of a modeled vesicle under a time-varying magnetic field. Following previous publications and to simplify the calculation, this model treated the inner and suspending media as lossy dielectrics, the membrane thickness set at zero, and the electric resistance of the membrane assumed to be negligible. This work provided the first analytical solutions for the surface charges, electric field, radial pressure, overall translational forces, and rotational torques introduced on a vesicle by the time-varying magnetic field. Frequency responses of these measures were analyzed, particularly the frequency used clinically by transcranial magnetic stimulation (TMS). The induced surface charges interacted with the electric field to produce a biomechanical impact upon the vesicle. The distribution of the induced surface charges depended on the orientation of the coil and field frequency. The densities of these charges were trivial at low frequency ranges, but significant at high frequency ranges. The direction of the radial force on the vesicle was dependent on the conductivity ratio between the vesicle and the medium. At relatively low frequencies (<200 KHz), including the frequency used in TMS, the computed radial pressure and translational forces on the vesicle were both negligible. This work

Assessing changes in the physico-chemical properties and fluoride adsorption capacity of activated alumina under varied conditions

USGS Publications Warehouse

Craig, Laura; Stillings, Lisa; Decker, David L.

2017-01-01

Adsorption using activated alumina is a simple method for removing fluoride from drinking water, but to be cost effective the adsorption capacity must be high and effective long-term. The intent of this study was to assess changes in its adsorption capacity under varied conditions. This was determined by evaluating the physico-chemical properties, surface charge, and fluoride (F−) adsorption capacity and rate of activated alumina under conditions such as hydration period, particle size, and slow vs. fast titrations. X-ray diffraction and scanning electron microscopy analyses show that the mineralogy of activated alumina transformed to boehmite, then bayerite with hydration period and a corresponding reduction in adsorption capacity was expected; while surface area analyses show no notable changes with hydration period or particle size. The pH dependent surface charge was three times higher using slow potentiometric titrations as compared to fast titrations (due largely to diffusion into pore space), with the surface acidity generally unaffected by hydration period. Results from batch adsorption experiments similarly show no change in fluoride adsorption capacity with hydration period. There was also no notable difference in fluoride adsorption capacity between the particle size ranges of 0.5–1.0 mm and 0.125–0.250 mm, or with hydration period. However, adsorption rate increased dramatically with the finer particle sizes: at an initial F− concentration of 0.53 mmol L−1 (10 mg L−1), 90% was adsorbed in the 0.125–0.250 mm range after 1 h, while the 0.5–1.0 mm range required 24 h to achieve 90% adsorption. Also, the pseudo-second-order adsorption rate constants for the finer vs. larger particle sizes were 3.7 and 0.5 g per mmol F− per min respectively (24 h); and the initial intraparticle diffusion rate of the former was 2.6 times faster than the latter. The results show that adsorption capacity of activated alumina remains consistent and

The Impact of Varying Statutory Arrangements on Spatial Data Sharing and Access in Regional NRM Bodies

NASA Astrophysics Data System (ADS)

Paudyal, D. R.; McDougall, K.; Apan, A.

2014-12-01

Spatial information plays an important role in many social, environmental and economic decisions and increasingly acknowledged as a national resource essential for wider societal and environmental benefits. Natural Resource Management is one area where spatial information can be used for improved planning and decision making processes. In Australia, state government organisations are the custodians of spatial information necessary for natural resource management and regional NRM bodies are responsible to regional delivery of NRM activities. The access and sharing of spatial information between government agencies and regional NRM bodies is therefore as an important issue for improving natural resource management outcomes. The aim of this paper is to evaluate the current status of spatial information access, sharing and use with varying statutory arrangements and its impacts on spatial data infrastructure (SDI) development in catchment management sector in Australia. Further, it critically examined whether any trends and significant variations exist due to different institutional arrangements (statutory versus non-statutory) or not. A survey method was used to collect primary data from 56 regional natural resource management (NRM) bodies responsible for catchment management in Australia. Descriptive statistics method was used to show the similarities and differences between statutory and non-statutory arrangements. The key factors which influence sharing and access to spatial information are also explored. The results show the current statutory and administrative arrangements and regional focus for natural resource management is reasonable from a spatial information management perspective and provides an opportunity for building SDI at the catchment scale. However, effective institutional arrangements should align catchment SDI development activities with sub-national and national SDI development activities to address catchment management issues. We found minor

Effects of growing location on the production of main active components and antioxidant activity of Dasiphora fruticosa (L.) Rydb. by chemometric methods.

PubMed

Liu, Wei; Wang, Dongmei; Hou, Xiaogai; Yang, Yueqin; Xue, Xian; Jia, Qishi; Zhang, Lixia; Zhao, Wei; Yin, Dongxue

2018-05-17

Traditional Chinese medicine (TCM) plays a very important role in the health system of China. The content and activity of active component are main indexes that evaluate the quality of TCM, however they may vary with environmental factors in their growing locations. In this study, effects of environmental factors on the contents of active components and antioxidant activity of Dasiphora fruticosa from the five main production areas of China were investigated. The contents of tannin, total flavonoid and rutin were determined and varied within the range of 7.65-10.69%, 2.30-5.39% and 0.18-0.81%, respectively. Antioxidant activity was determined by DPPH assay, with the DPPH IC 50 values ranged from 8.791 to 32.534μg mL -1 . In order to further explore the cause of these significant geographical variations, the chemometric methods including correlation analysis, principal component analysis, gray correlation analysis, and path analysis were conducted. The results showed environmental factors had significant effect on the active component contents and antioxidant activity. Rapidly available phosphorus (RAP) and rapidly available nitrogen (RAN) were common dominant factors, and a significant positive correlation was observed between RAP and active components and antioxidant activity (P<0.05). Contributed by their high active components and strong antioxidant activity, Bange in Tibet and Geermu in Qinghai Province was selected as a favorable growing location, respectively. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Contextual Variability in Personality From Significant-Other Knowledge and Relational Selves.

PubMed

Andersen, Susan M; Tuskeviciute, Rugile; Przybylinski, Elizabeth; Ahn, Janet N; Xu, Joy H

2015-01-01

We argue that the self is intrinsically embedded in an interpersonal context such that it varies in IF-THEN terms, as the relational self. We have demonstrated that representations of the significant other and the relationship with that other are automatically activated by situational cues and that this activation affects both experienced and expressed aspects of the self and personality. Here, we expand on developments of the IF-THEN cognitive-affective framework of personality system (Mischel and Shoda, 1995), by extending it to the domain of interpersonal relationships at the dyadic level (Andersen and Chen, 2002). Going beyond Mischel's early research (Mischel, 1968), our framework combines social cognition and learning theory with a learning-based psychodynamic approach, which provides the basis for extensive research on the social-cognitive process of transference and the relational self as it arises in everyday social interactions (Andersen and Cole, 1990), evidence from which contributes to a modern conceptualization of personality that emphasizes the centrality of the situation.

Time-varying long term memory in the European Union stock markets

NASA Astrophysics Data System (ADS)

Sensoy, Ahmet; Tabak, Benjamin M.

2015-10-01

This paper proposes a new efficiency index to model time-varying inefficiency in stock markets. We focus on European stock markets and show that they have different degrees of time-varying efficiency. We observe that the 2008 global financial crisis has an adverse effect on almost all EU stock markets. However, the Eurozone sovereign debt crisis has a significant adverse effect only on the markets in France, Spain and Greece. For the late members, joining EU does not have a uniform effect on stock market efficiency. Our results have important implications for policy makers, investors, risk managers and academics.

LASR-Guided Variability Subtraction: The Linear Algorithm for Significance Reduction of Stellar Seismic Activity

NASA Astrophysics Data System (ADS)

Horvath, Sarah; Myers, Sam; Ahlers, Johnathon; Barnes, Jason W.

2017-10-01

Stellar seismic activity produces variations in brightness that introduce oscillations into transit light curves, which can create challenges for traditional fitting models. These oscillations disrupt baseline stellar flux values and potentially mask transits. We develop a model that removes these oscillations from transit light curves by minimizing the significance of each oscillation in frequency space. By removing stellar variability, we prepare each light curve for traditional fitting techniques. We apply our model to $\\delta$-Scuti KOI-976 and demonstrate that our variability subtraction routine successfully allows for measuring bulk system characteristics using traditional light curve fitting. These results open a new window for characterizing bulk system parameters of planets orbiting seismically active stars.

Work activity in food service: The significance of customer relations, tipping practices and gender for preventing musculoskeletal disorders.

PubMed

Laperrière, Ève; Messing, Karen; Bourbonnais, Renée

2017-01-01

Some evidence shows that food servers are exposed to an elevated risk of musculoskeletal disorders and injuries, and that their work activity varies by gender. Interviews of servers and observations of food service in Québec, Canada, were carried out in three restaurants and a questionnaire was administered to 64 workers from 44 other restaurants. The relationship with the customer has specific effects on work activity and transforms the physical, emotional and cognitive work. Strategies intended to speed service or otherwise related to the customer relationship can involve health risks. Women reported more direct food service (p < 0.01), a tendency to do more "housekeeping" tasks (p < 0.07) and fewer hours of work per week (p < 0.01). Women workers reported experiencing more sites of pain (p < 0.003). This exploratory study suggests that managing the server-customer relationship could be important in preventing musculoskeletal disorders in this population and that women are at particular risk. Copyright © 2016 Elsevier Ltd. All rights reserved.

Tendon material properties vary and are interdependent among turkey hindlimb muscles.

PubMed

Matson, Andrew; Konow, Nicolai; Miller, Samuel; Konow, Pernille P; Roberts, Thomas J

2012-10-15

The material properties of a tendon affect its ability to store and return elastic energy, resist damage, provide mechanical feedback and amplify or attenuate muscle power. While the structural properties of a tendon are known to respond to a variety of stimuli, the extent to which material properties vary among individual muscles remains unclear. We studied the tendons of six different muscles in the hindlimb of Eastern wild turkeys to determine whether there was variation in elastic modulus, ultimate tensile strength and resilience. A hydraulic testing machine was used to measure tendon force during quasi-static lengthening, and a stress-strain curve was constructed. There was substantial variation in tendon material properties among different muscles. Average elastic modulus differed significantly between some tendons, and values for the six different tendons varied nearly twofold, from 829±140 to 1479±106 MPa. Tendons were stretched to failure, and the stress at failure, or ultimate tensile stress, was taken as a lower-limit estimate of tendon strength. Breaking tests for four of the tendons revealed significant variation in ultimate tensile stress, ranging from 66.83±14.34 to 112.37±9.39 MPa. Resilience, or the fraction of energy returned in cyclic length changes was generally high, and one of the four tendons tested was significantly different in resilience from the other tendons (range: 90.65±0.83 to 94.02±0.71%). An analysis of correlation between material properties revealed a positive relationship between ultimate tensile strength and elastic modulus (r(2)=0.79). Specifically, stiffer tendons were stronger, and we suggest that this correlation results from a constrained value of breaking strain, which did not vary significantly among tendons. This finding suggests an interdependence of material properties that may have a structural basis and may explain some adaptive responses observed in studies of tendon plasticity.

Genetic and biochemical characterization of OXA-405, an OXA-48-type extended-spectrum β-lactamase without significant carbapenemase activity.

PubMed

Dortet, Laurent; Oueslati, Saoussen; Jeannot, Katy; Tandé, Didier; Naas, Thierry; Nordmann, Patrice

2015-07-01

The epidemiology of carbapenemases worldwide is showing that OXA-48 variants are becoming the predominant carbapenemase type in Enterobacteriaceae in many countries. However, not all OXA-48 variants possess significant activity toward carbapenems (e.g., OXA-163). Two Serratia marcescens isolates with resistance either to carbapenems or to extended-spectrum cephalosporins were successively recovered from the same patient. A genomic comparison using pulsed-field gel electrophoresis and automated Rep-PCR typing identified a 97.8% similarity between the two isolates. Both strains were resistant to penicillins and first-generation cephalosporins. The first isolate was susceptible to expanded-spectrum cephalosporins, was resistant to carbapenems, and had a significant carbapenemase activity (positive Carba NP test) related to the expression of OXA-48. The second isolate was resistant to expanded-spectrum cephalosporins, was susceptible to carbapenems, and did not express a significant imipenemase activity, (negative for the Carba NP test) despite possessing a blaOXA-48-type gene. Sequencing identified a novel OXA-48-type β-lactamase, OXA-405, with a four-amino-acid deletion compared to OXA-48. The blaOXA-405 gene was located on a ca. 46-kb plasmid identical to the prototype IncL/M blaOXA-48-carrying plasmid except for a ca. 16.4-kb deletion in the tra operon, leading to the suppression of self-conjugation properties. Biochemical analysis showed that OXA-405 has clavulanic acid-inhibited activity toward expanded-spectrum activity without significant imipenemase activity. This is the first identification of a successive switch of catalytic activity in OXA-48-like β-lactamases, suggesting their plasticity. Therefore, this report suggests that the first-line screening of carbapenemase producers in Enterobacteriaceae may be based on the biochemical detection of carbapenemase activity in clinical settings. Copyright © 2015, American Society for Microbiology. All Rights

An fMRI study of joint action–varying levels of cooperation correlates with activity in control networks

PubMed Central

Chaminade, Thierry; Marchant, Jennifer L.; Kilner, James; Frith, Christopher D.

2012-01-01

As social agents, humans continually interact with the people around them. Here, motor cooperation was investigated using a paradigm in which pairs of participants, one being scanned with fMRI, jointly controlled a visually presented object with joystick movements. The object oscillated dynamically along two dimensions, color and width of gratings, corresponding to the two cardinal directions of joystick movements. While the overall control of each participant on the object was kept constant, the amount of cooperation along the two dimensions varied along four levels, from no (each participant controlled one dimension exclusively) to full (each participant controlled half of each dimension) cooperation. Increasing cooperation correlated with BOLD signal in the left parietal operculum and anterior cingulate cortex (ACC), while decreasing cooperation correlated with activity in the right inferior frontal and superior temporal gyri, the intraparietal sulci and inferior temporal gyri bilaterally, and the dorsomedial prefrontal cortex. As joint performance improved with the level of cooperation, we assessed the brain responses correlating with behavior, and found that activity in most of the areas associated with levels of cooperation also correlated with the joint performance. The only brain area found exclusively in the negative correlation with cooperation was in the dorso medial frontal cortex, involved in monitoring action outcome. Given the cluster location and condition-related signal change, we propose that this region monitored actions to extract the level of cooperation in order to optimize the joint response. Our results, therefore, indicate that, in the current experimental paradigm involving joint control of a visually presented object with joystick movements, the level of cooperation affected brain networks involved in action control, but not mentalizing. PMID:22715326

A Smartphone Application Significantly Improved Diabetes Self-Care Activities with High User Satisfaction

PubMed Central

Kim, Yu Jin; Byun, Jong Kyu; Park, So Young; Hong, Soo Min; Chin, Sang Ouk; Chon, Suk; Oh, Seungjoon; Woo, Jeong-taek; Kim, Sung Woon; Kim, Young Seol

2015-01-01

Background We developed for the first time a smartphone application designed for diabetes self-management in Korea and registered a patent for the relevant algorithm. We also investigated the user satisfaction with the application and the change in diabetes related self-care activities after using the application. Methods We conducted a questionnaire survey on volunteers with diabetes who were using the application. Ninety subjects responded to the questionnaire between June 2012 and March 2013. A modified version of the Summary of Diabetes Self-Care Activities (SDSCA) was used in this study. Results The survey results exhibited a mean subject age of 44.0 years old, and males accounted for 78.9% of the subjects. Fifty percent of the subjects had diabetes for less than 3 years. The majority of respondents experienced positive changes in their clinical course after using the application (83.1%) and were satisfied with the structure and completeness of the application (86.7%). Additionally, the respondents' answers indicated that the application was easy to use (96.7%) and recommendable to others (97.7%) and that they would continue using the application to manage their diabetes (96.7%). After using the Diabetes Notepad application, diabetes related self-care activities assessed by SDSCA displayed statistically significant improvements (P<0.05), except for the number of days of drinking. Conclusion This smartphone-based application can be a useful tool leading to positive changes in diabetes related self-care activities and increase user satisfaction. PMID:26124991

Estimation of Time-Varying Pilot Model Parameters

NASA Technical Reports Server (NTRS)

Zaal, Peter M. T.; Sweet, Barbara T.

2011-01-01

Human control behavior is rarely completely stationary over time due to fatigue or loss of attention. In addition, there are many control tasks for which human operators need to adapt their control strategy to vehicle dynamics that vary in time. In previous studies on the identification of time-varying pilot control behavior wavelets were used to estimate the time-varying frequency response functions. However, the estimation of time-varying pilot model parameters was not considered. Estimating these parameters can be a valuable tool for the quantification of different aspects of human time-varying manual control. This paper presents two methods for the estimation of time-varying pilot model parameters, a two-step method using wavelets and a windowed maximum likelihood estimation method. The methods are evaluated using simulations of a closed-loop control task with time-varying pilot equalization and vehicle dynamics. Simulations are performed with and without remnant. Both methods give accurate results when no pilot remnant is present. The wavelet transform is very sensitive to measurement noise, resulting in inaccurate parameter estimates when considerable pilot remnant is present. Maximum likelihood estimation is less sensitive to pilot remnant, but cannot detect fast changes in pilot control behavior.

Morphable Word Clouds for Time-Varying Text Data Visualization.

PubMed

Chi, Ming-Te; Lin, Shih-Syun; Chen, Shiang-Yi; Lin, Chao-Hung; Lee, Tong-Yee

2015-12-01

A word cloud is a visual representation of a collection of text documents that uses various font sizes, colors, and spaces to arrange and depict significant words. The majority of previous studies on time-varying word clouds focuses on layout optimization and temporal trend visualization. However, they do not fully consider the spatial shapes and temporal motions of word clouds, which are important factors for attracting people's attention and are also important cues for human visual systems in capturing information from time-varying text data. This paper presents a novel method that uses rigid body dynamics to arrange multi-temporal word-tags in a specific shape sequence under various constraints. Each word-tag is regarded as a rigid body in dynamics. With the aid of geometric, aesthetic, and temporal coherence constraints, the proposed method can generate a temporally morphable word cloud that not only arranges word-tags in their corresponding shapes but also smoothly transforms the shapes of word clouds over time, thus yielding a pleasing time-varying visualization. Using the proposed frame-by-frame and morphable word clouds, people can observe the overall story of a time-varying text data from the shape transition, and people can also observe the details from the word clouds in frames. Experimental results on various data demonstrate the feasibility and flexibility of the proposed method in morphable word cloud generation. In addition, an application that uses the proposed word clouds in a simulated exhibition demonstrates the usefulness of the proposed method.

Efficient Encoding and Rendering of Time-Varying Volume Data

NASA Technical Reports Server (NTRS)

Ma, Kwan-Liu; Smith, Diann; Shih, Ming-Yun; Shen, Han-Wei

1998-01-01

Visualization of time-varying volumetric data sets, which may be obtained from numerical simulations or sensing instruments, provides scientists insights into the detailed dynamics of the phenomenon under study. This paper describes a coherent solution based on quantization, coupled with octree and difference encoding for visualizing time-varying volumetric data. Quantization is used to attain voxel-level compression and may have a significant influence on the performance of the subsequent encoding and visualization steps. Octree encoding is used for spatial domain compression, and difference encoding for temporal domain compression. In essence, neighboring voxels may be fused into macro voxels if they have similar values, and subtrees at consecutive time steps may be merged if they are identical. The software rendering process is tailored according to the tree structures and the volume visualization process. With the tree representation, selective rendering may be performed very efficiently. Additionally, the I/O costs are reduced. With these combined savings, a higher level of user interactivity is achieved. We have studied a variety of time-varying volume datasets, performed encoding based on data statistics, and optimized the rendering calculations wherever possible. Preliminary tests on workstations have shown in many cases tremendous reduction by as high as 90% in both storage space and inter-frame delay.

Emotion regulation ability varies in relation to intrinsic functional brain architecture.

PubMed

Uchida, Mai; Biederman, Joseph; Gabrieli, John D E; Micco, Jamie; de Los Angeles, Carlo; Brown, Ariel; Kenworthy, Tara; Kagan, Elana; Whitfield-Gabrieli, Susan

2015-12-01

This study investigated the neural basis of individual variation in emotion regulation, specifically the ability to reappraise negative stimuli so as to down-regulate negative affect. Brain functions in young adults were measured with functional Magnetic Resonance Imaging during three conditions: (i) attending to neutral pictures; (ii) attending to negative pictures and (iii) reappraising negative pictures. Resting-state functional connectivity was measured with amygdala and dorsolateral prefrontal cortical (DLPFC) seed regions frequently associated with emotion regulation. Participants reported more negative affect after attending to negative than neutral pictures, and less negative affect following reappraisal. Both attending to negative vs neutral pictures and reappraising vs attending to negative pictures yielded widespread activations that were significantly right-lateralized for attending to negative pictures and left-lateralized for reappraising negative pictures. Across participants, more successful reappraisal correlated with less trait anxiety and more positive daily emotion, greater activation in medial and lateral prefrontal regions, and lesser resting-state functional connectivity between (a) right amygdala and both medial prefrontal and posterior cingulate cortices, and (b) bilateral DLPFC and posterior visual cortices. The ability to regulate emotion, a source of resilience or of risk for distress, appears to vary in relation to differences in intrinsic functional brain architecture. © The Author (2015). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

One stone, two birds: silica nanospheres significantly increase photocatalytic activity and colloidal stability of photocatalysts

NASA Astrophysics Data System (ADS)

Rasamani, Kowsalya D.; Foley, Jonathan J., IV; Sun, Yugang

2018-03-01

Silver-doped silver chloride [AgCl(Ag)] nanoparticles represent a unique class of visible-light-driven photocatalysts, in which the silver dopants introduce electron-abundant mid-gap energy levels to lower the bandgap of AgCl. However, free-standing AgCl(Ag) nanoparticles, particularly those with small sizes and large surface areas, exhibit low colloidal stability and low compositional stability upon exposure to light irradiation, leading to easy aggregation and conversion to metallic silver and thus a loss of photocatalytic activity. These problems could be eliminated by attaching the small AgCl(Ag) nanoparticles to the surfaces of spherical dielectric silica particles with submicrometer sizes. The high optical transparency in the visible spectral region (400-800 nm), colloidal stability, and chemical/electronic inertness displayed by the silica spheres make them ideal for supporting photocatalysts and significantly improving their stability. The spherical morphology of the dielectric silica particles can support light scattering resonances to generate significantly enhanced electric fields near the silica particle surfaces, on which the optical absorption cross-section of the AgCl(Ag) nanoparticles is dramatically increased to promote their photocatalytic activity. The hybrid silica/AgCl(Ag) structures exhibit superior photocatalytic activity and stability, suitable for supporting photocatalysis sustainably; for instance, their efficiency in the photocatalytic decomposition of methylene blue decreases by only ˜9% even after ten cycles of operation.

Gender Differences in Barriers to Physical Activity among College Students Reporting Varying Levels of Regular Physical Activity

ERIC Educational Resources Information Center

Munford, Shawn N.

2011-01-01

Researchers have studied the primary determinants of physical activity in an effort to enhance health promotion initiatives nationwide. These physical activity determinants have been observed to differ among various segments of the population, suggesting a further examination of physical activity barriers among differing populations. Little…

Differential sensitivity of spinach and amaranthus to enhanced UV-B at varying soil nutrient levels: association with gas exchange, UV-B-absorbing compounds and membrane damage.

PubMed

Singh, Suruchi; Agrawal, Madhoolika; Agrawal, S B

2013-07-01

The metabolic reasons associated with differential sensitivity of C3 and C4 plant species to enhanced UV-B under varying soil nutrient levels are not well understood. In the present study, spinach (Spinacia oleracea L. var All Green), a C3 and amaranthus (Amaranthus tricolor L. var Pusa Badi Chaulai), a C4 plant were subjected to enhanced UV-B (280-315 nm; 7.2 kJ m(-2) day(-1)) over ambient under varying soil nutrient levels. The nutrient amendments were recommended Nitrogen (N), Phosphorus (P), Potassium (K), 1.5× recommended NPK, 1.5× recommended N and 1.5× recommended K. Enhanced UV-B negatively affected both the species at all nutrient levels, but the reductions varied with nutrient concentration and combinations. Reductions in photosynthetic rate, stomatal conductance and chlorophyll content were significantly more in spinach compared with amaranthus. The reduction in photosynthetic rate was maximum at 1.5× recommended K and minimum in 1.5× NPK amended plants. The oxidative damage to membranes measured in terms of malondialdehyde content was significantly higher in spinach compared with amaranthus. Enhanced UV-B reduced SOD activity in both the plants except in amaranthus at 1.5× recommended K. POX activity increased under enhanced UV-B at all nutrient levels in amaranthus, but only at 1.5× K in spinach. Amaranthus had significantly higher UV-B-absorbing compounds than spinach even under UV-B stress. Lowest reductions in yield and total biomass under enhanced UV-B compared with ambient were observed in amaranthus grown at 1.5× recommended NPK. Enhanced UV-B did not significantly change the nitrogen use efficiency in amaranthus at all NPK levels, but reduced in spinach except at 1.5× K. These findings suggest that the differential sensitivity of the test species under enhanced UV-B at varying nutrient levels is due to varying antioxidative and UV-B screening capacity, and their ability to utilize nutrients. Amaranthus tolerated enhanced UV-B stress

Motoneuron and sensory neuron plasticity to varying neuromuscular activity levels

NASA Technical Reports Server (NTRS)

Ishihara, Akihiko; Roy, Roland R.; Ohira, Yoshinobu; Edgerton, V. Reggie

2002-01-01

The size and phenotypic properties of the neural and muscular elements of the neuromuscular unit are matched under normal conditions. When subjected to chronic decreases or increases in neuromuscular activity, however, the adaptations in these properties are much more limited in the neural compared with the muscular elements.

The home physical activity environment and adolescent BMI, physical activity and TV viewing: Disparities across a diverse sample.

PubMed

Eisenberg, Marla E; Larson, Nicole I; Berge, Jerica M; Thul, Chelsey; Neumark-Sztainer, Dianne

2014-12-01

Characteristics of the home and family have been associated with adolescents' BMI and physical and sedentary activity, but few studies have examined how these characteristics vary across ethnic/racial groups. This study explores whether recommendations for activity promotion are equally relevant to different adolescent populations. Participants included 2,374 adolescents and their parent(s), recruited through 20 public schools in Minneapolis/St. Paul, MN in 2009-2010. Ethnic/racial groups included African American, Asian (primarily Hmong), East African, Hispanic, Native American, White, and mixed/other race. Linear regression analysis modeled adolescents' BMI z-scores and physical and sedentary activity based on six measures of the family/home activity environment, adjusted for covariates. Interactions of ethnicity/race and family/home environment were tested. All six family/home environment measures varied significantly across ethnicity/race. Family/home variables were significantly associated with adolescent physical activity and TV viewing in the expected directions, and these relationships were consistent across ethnic/racial groups in two-thirds of the models. However, in one-third of the cases, these associations were modified by ethnicity/race. For example, home access to a greater number of media devices was significantly associated with more TV viewing (β=.40, p=.015) only among White youth. Health promotion recommendations for adolescent physical activity are largely relevant across ethnic/racial groups. However, given differences found in the family/home environments of adolescents, cultural sensitivity is recommended in discussing these issues, and tailored recommendations may be appropriate for select groups or behaviors. Further mixed methods research is warranted to help identify key messages for specific groups.

Investigating the Relationship between Instructors’ Use of Active-Learning Strategies and Students’ Conceptual Understanding and Affective Changes in Introductory Biology: A Comparison of Two Active-Learning Environments

PubMed Central

Cleveland, Lacy M.; Olimpo, Jeffrey T.; DeChenne-Peters, Sue Ellen

2017-01-01

In response to calls for reform in undergraduate biology education, we conducted research examining how varying active-learning strategies impacted students’ conceptual understanding, attitudes, and motivation in two sections of a large-lecture introductory cell and molecular biology course. Using a quasi-experimental design, we collected quantitative data to compare participants’ conceptual understanding, attitudes, and motivation in the biological sciences across two contexts that employed different active-learning strategies and that were facilitated by unique instructors. Students participated in either graphic organizer/worksheet activities or clicker-based case studies. After controlling for demographic and presemester affective differences, we found that students in both active-learning environments displayed similar and significant learning gains. In terms of attitudinal and motivational data, significant differences were observed for two attitudinal measures. Specifically, those students who had participated in graphic organizer/worksheet activities demonstrated more expert-like attitudes related to their enjoyment of biology and ability to make real-world connections. However, all motivational and most attitudinal data were not significantly different between the students in the two learning environments. These data reinforce the notion that active learning is associated with conceptual change and suggests that more research is needed to examine the differential effects of varying active-learning strategies on students’ attitudes and motivation in the domain. PMID:28389428

Activation Dependence of Stretch Activation in Mouse Skinned Myocardium: Implications for Ventricular Function

PubMed Central

Stelzer, Julian E.; Larsson, Lars; Fitzsimons, Daniel P.; Moss, Richard L.

2006-01-01

Recent evidence suggests that ventricular ejection is partly powered by a delayed development of force, i.e., stretch activation, in regions of the ventricular wall due to stretch resulting from torsional twist of the ventricle around the apex-to-base axis. Given the potential importance of stretch activation in cardiac function, we characterized the stretch activation response and its Ca2+ dependence in murine skinned myocardium at 22°C in solutions of varying Ca2+ concentrations. Stretch activation was induced by suddenly imposing a stretch of 0.5–2.5% of initial length to the isometrically contracting muscle and then holding the muscle at the new length. The force response to stretch was multiphasic: force initially increased in proportion to the amount of stretch, reached a peak, and then declined to a minimum before redeveloping to a new steady level. This last phase of the response is the delayed force characteristic of myocardial stretch activation and is presumably due to increased attachment of cross-bridges as a consequence of stretch. The amplitude and rate of stretch activation varied with Ca2+ concentration and more specifically with the level of isometric force prior to the stretch. Since myocardial force is regulated both by Ca2+ binding to troponin-C and cross-bridge binding to thin filaments, we explored the role of cross-bridge binding in the stretch activation response using NEM-S1, a strong-binding, non-force–generating derivative of myosin subfragment 1. NEM-S1 treatment at submaximal Ca2+-activated isometric forces significantly accelerated the rate of the stretch activation response and reduced its amplitude. These data show that the rate and amplitude of myocardial stretch activation vary with the level of activation and that stretch activation involves cooperative binding of cross-bridges to the thin filament. Such a mechanism would contribute to increased systolic ejection in response to increased delivery of activator Ca2+ during

Haemolytic activity of soil from areas of varying podoconiosis endemicity in Ethiopia

PubMed Central

Le Blond, Jennifer S.; Baxter, Peter J.; Bello, Dhimiter; Raftis, Jennifer; Molla, Yordanos B.; Cuadros, Javier; Davey, Gail

2017-01-01

Background Podoconiosis, non-filarial elephantiasis, is a non-infectious disease found in tropical regions such as Ethiopia, localized in highland areas with volcanic soils cultivated by barefoot subsistence farmers. It is thought that soil particles can pass through the soles of the feet and taken up by the lymphatic system, leading to the characteristic chronic oedema of the lower legs that becomes disfiguring and disabling over time. Methods The close association of the disease with volcanic soils led us to investigate the characteristics of soil samples in an endemic area in Ethiopia to identify the potential causal constituents. We used the in vitro haemolysis assay and compared haemolytic activity (HA) with soil samples collected in a non-endemic region of the same area in Ethiopia. We included soil samples that had been previously characterized, in addition we present other data describing the characteristics of the soil and include pure phase mineral standards as comparisons. Results The bulk chemical composition of the soils were statistically significantly different between the podoconiosis-endemic and non-endemic areas, with the exception of CaO and Cr. Likewise, the soil mineralogy was statistically significant for iron oxide, feldspars, mica and chlorite. Smectite and kaolinite clays were widely present and elicited a strong HA, as did quartz, in comparison to other mineral phases tested, although no strong difference was found in HA between soils from the two areas. The relationship was further investigated with principle component analysis (PCA), which showed that a combination of an increase in Y, Zr and Al2O3, and a concurrent increase Fe2O3, TiO2, MnO and Ba in the soils increased HA. Conclusion The mineralogy and chemistry of the soils influenced the HA, although the interplay between the components is complex. Further research should consider the variable biopersistance, hygroscopicity and hardness of the minerals and further characterize the

Activation of the hip adductor muscles varies during a simulated weight-bearing task.

PubMed

Hides, Julie A; Beall, Paula; Franettovich Smith, Melinda M; Stanton, Warren; Miokovic, Tanja; Richardson, Carolyn

2016-01-01

To investigate the pattern of muscle activation of the individual hip adductor muscles using a standardised simulated unilateral weight-bearing task. A repeated measures design. Laboratory. 20 healthy individuals (11 females, 9 males) participated in the study. Age ranged from 20 to 25 years. Surface electromyography recordings from adductor magnus and adductor longus muscles were taken at levels representing 10-50% of body weight during a simulated weight-bearing task. Electromyography (EMG) data were normalised to maximal voluntary isometric contraction. The adductor magnus was recruited at significantly higher levels than the adductor longus muscle during a simulated weight-bearing task performed across 10-50% of body weight (p < 0.01). Adductor magnus and adductor longus muscles are recruited to different extents during a simulated weight-bearing task. This information should be considered when selecting exercises for management and prevention of groin strains. Closed chain exercises with weight-bearing through the lower limb are more likely to recruit the adductor magnus muscle over the adductor longus muscle. Copyright © 2015 Elsevier Ltd. All rights reserved.

Stem phototropism of trees: a possible significant factor in determining stem inclination on forest slopes.

PubMed

Matsuzaki, Jun; Masumori, Masaya; Tange, Takeshi

2006-09-01

The main stems of trees on forest slopes incline down the slope to various extents that are characteristic of the species. The inclination has been explained as an active response to a horizontally asymmetrical light environment, but the contributing physiological mechanisms are unknown. The present study tested the hypothesis that stem phototropism, gravitropism, or a combination of the two determines the inclination of tree stems on forest slopes. Cryptomeria japonica, Pinus densiflora, Quercus myrsinaefolia and Q. serrata were studied. Measurements were made of stem inclination of mature trees on forest slopes in uniform plantations of each species, and changes in stem inclination of potted seedlings in response to illumination treatments (unilateral or overhead) and inclination treatments (artificially inclined or erect). Indices of phototropic and gravitropic responsiveness were evaluated for each species, calculated from the change in stem inclination in response to artificial inclination with unilateral or overhead illumination. Stem inclination on forest slopes varied significantly among species: Q. serrata inclined most in the down-slope direction, C. japonica inclined the least, and P. densiflora and Q. myrsinaefolia were intermediate. The change in stem inclination of seedlings in each treatment varied significantly among species. One-year-old stems of Q. serrata and 2-year-old stems of Q. myrsinaefolia bent toward the light source. Interspecific variation in the change in stem inclination in response to the unilateral illumination or that in the index of phototropic responsiveness was strongly correlated with the variation in stem inclination on forest slopes. The orientation of woody stems that have finished elongation can be actively controlled by phototropism. Interspecific variation in phototropic responsiveness of trees is a possible significant determinant of interspecific variation in stem inclination on forest slopes.

Stem Phototropism of Trees: A Possible Significant Factor in Determining Stem Inclination on Forest Slopes

PubMed Central

MATSUZAKI, JUN; MASUMORI, MASAYA; TANGE, TAKESHI

2006-01-01

• Background and Aims The main stems of trees on forest slopes incline down the slope to various extents that are characteristic of the species. The inclination has been explained as an active response to a horizontally asymmetrical light environment, but the contributing physiological mechanisms are unknown. The present study tested the hypothesis that stem phototropism, gravitropism, or a combination of the two determines the inclination of tree stems on forest slopes. • Methods Cryptomeria japonica, Pinus densiflora, Quercus myrsinaefolia and Q. serrata were studied. Measurements were made of stem inclination of mature trees on forest slopes in uniform plantations of each species, and changes in stem inclination of potted seedlings in response to illumination treatments (unilateral or overhead) and inclination treatments (artificially inclined or erect). Indices of phototropic and gravitropic responsiveness were evaluated for each species, calculated from the change in stem inclination in response to artificial inclination with unilateral or overhead illumination. • Key Results Stem inclination on forest slopes varied significantly among species: Q. serrata inclined most in the down-slope direction, C. japonica inclined the least, and P. densiflora and Q. myrsinaefolia were intermediate. The change in stem inclination of seedlings in each treatment varied significantly among species. One-year-old stems of Q. serrata and 2-year-old stems of Q. myrsinaefolia bent toward the light source. Interspecific variation in the change in stem inclination in response to the unilateral illumination or that in the index of phototropic responsiveness was strongly correlated with the variation in stem inclination on forest slopes. • Conclusions The orientation of woody stems that have finished elongation can be actively controlled by phototropism. Interspecific variation in phototropic responsiveness of trees is a possible significant determinant of interspecific

Hemolymph drop impact outcomes on surfaces with varying wettability

NASA Astrophysics Data System (ADS)

Milionis, Athanasios; Ghokulla Krishnan, K.; Loth, Eric

2015-08-01

Insect fouling from coagulated hemolymph and exoskeleton parts is a major challenge in the aerospace industry for the next generation of aerodynamic surfaces, which will employ laminar flow that requires extremely smooth surfaces. However, the wetting physics and dynamics of hemolymph (insect blood) on surfaces are not well understood. The present study seeks to gain a fundamental insight on the effect of surface wetting characteristics and dynamics resulting from a hemolymph drop impact, the first such study. In particular, hemolymph drops extracted from Acheta domesticus were dispensed from a range of heights to vary the kinetic impact on surfaces, which had widely varying water wetting behavior (from superhydrophilic to superhydrophobic). The impact dynamics were investigated with high-speed imaging while the dried residues were studied with optical microscopy. It was found that a superhydrophobic surface (based on thermoplastic with silica nano-particles) was able to significantly reduce hemolymph drop spreading, and even provide complete rebound when impacting on inclined surfaces.

Tendon material properties vary and are interdependent among turkey hindlimb muscles

PubMed Central

Matson, Andrew; Konow, Nicolai; Miller, Samuel; Konow, Pernille P.; Roberts, Thomas J.

2012-01-01

SUMMARY The material properties of a tendon affect its ability to store and return elastic energy, resist damage, provide mechanical feedback and amplify or attenuate muscle power. While the structural properties of a tendon are known to respond to a variety of stimuli, the extent to which material properties vary among individual muscles remains unclear. We studied the tendons of six different muscles in the hindlimb of Eastern wild turkeys to determine whether there was variation in elastic modulus, ultimate tensile strength and resilience. A hydraulic testing machine was used to measure tendon force during quasi-static lengthening, and a stress–strain curve was constructed. There was substantial variation in tendon material properties among different muscles. Average elastic modulus differed significantly between some tendons, and values for the six different tendons varied nearly twofold, from 829±140 to 1479±106 MPa. Tendons were stretched to failure, and the stress at failure, or ultimate tensile stress, was taken as a lower-limit estimate of tendon strength. Breaking tests for four of the tendons revealed significant variation in ultimate tensile stress, ranging from 66.83±14.34 to 112.37±9.39 MPa. Resilience, or the fraction of energy returned in cyclic length changes was generally high, and one of the four tendons tested was significantly different in resilience from the other tendons (range: 90.65±0.83 to 94.02±0.71%). An analysis of correlation between material properties revealed a positive relationship between ultimate tensile strength and elastic modulus (r2=0.79). Specifically, stiffer tendons were stronger, and we suggest that this correlation results from a constrained value of breaking strain, which did not vary significantly among tendons. This finding suggests an interdependence of material properties that may have a structural basis and may explain some adaptive responses observed in studies of tendon plasticity. PMID:22771746

Dithiothreitol activity by particulate oxidizers of SOA produced from photooxidation of hydrocarbons under varied NOx levels

NASA Astrophysics Data System (ADS)

Jiang, Huanhuan; Jang, Myoseon; Yu, Zechen

2017-08-01

When hydrocarbons (HCs) are atmospherically oxidized, they form particulate oxidizers, including quinones, organic hydroperoxides, and peroxyacyl nitrates (PANs). These particulate oxidizers can modify cellular materials (e.g., proteins and enzymes) and adversely modulate cell functions. In this study, the contribution of particulate oxidizers in secondary organic aerosols (SOAs) to the oxidative potential was investigated. SOAs were generated from the photooxidation of toluene, 1,3,5-trimethylbenzene, isoprene, and α-pinene under varied NOx levels. Oxidative potential was determined from the typical mass-normalized consumption rate (reaction time t = 30 min) of dithiothreitol (DTTt), a surrogate for biological reducing agents. Under high-NOx conditions, the DTTt of toluene SOA was 2-5 times higher than that of the other types of SOA. Isoprene DTTt significantly decreased with increasing NOx (up to 69 % reduction by changing the HC / NOx ratio from 30 to 5). The DTTt of 1,3,5-trimethylbenzene and α-pinene SOA was insensitive to NOx under the experimental conditions of this study. The significance of quinones to the oxidative potential of SOA was tested through the enhancement of DTT consumption in the presence of 2,4-dimethylimidazole, a co-catalyst for the redox cycling of quinones; however, no significant effect of 2,4-dimethylimidazole on modulation of DTT consumption was observed for all SOA, suggesting that a negligible amount of quinones was present in the SOA of this study. For toluene and isoprene, mass-normalized DTT consumption (DTTm) was determined over an extended period of reaction time (t = 2 h) to quantify their maximum capacity to consume DTT. The total quantities of PANs and organic hydroperoxides in toluene SOA and isoprene SOA were also measured using the Griess assay and the 4-nitrophenylboronic acid assay, respectively. Under the NOx conditions (HC / NOx ratio: 5-36 ppbC ppb-1) applied in this study, the amount of organic hydroperoxides was

Adaptive significance of right hemisphere activation in aphasic language comprehension

PubMed Central

Meltzer, Jed A.; Wagage, Suraji; Ryder, Jennifer; Solomon, Beth; Braun, Allen R.

2013-01-01

Aphasic patients often exhibit increased right hemisphere activity during language tasks. This may represent takeover of function by regions homologous to the left-hemisphere language networks, maladaptive interference, or adaptation of alternate compensatory strategies. To distinguish between these accounts, we tested language comprehension in 25 aphasic patients using an online sentence-picture matching paradigm while measuring brain activation with MEG. Linguistic conditions included semantically irreversible (“The boy is eating the apple”) and reversible (“The boy is pushing the girl”) sentences at three levels of syntactic complexity. As expected, patients performed well above chance on irreversible sentences, and at chance on reversible sentences of high complexity. Comprehension of reversible non-complex sentences ranged from nearly perfect to chance, and was highly correlated with offline measures of language comprehension. Lesion analysis revealed that comprehension deficits for reversible sentences were predicted by damage to the left temporal lobe. Although aphasic patients activated homologous areas in the right temporal lobe, such activation was not correlated with comprehension performance. Rather, patients with better comprehension exhibited increased activity in dorsal fronto-parietal regions. Correlations between performance and dorsal network activity occurred bilaterally during perception of sentences, and in the right hemisphere during a post-sentence memory delay. These results suggest that effortful reprocessing of perceived sentences in short-term memory can support improved comprehension in aphasia, and that strategic recruitment of alternative networks, rather than homologous takeover, may account for some findings of right hemisphere language activation in aphasia. PMID:23566891

Einstein Equations from Varying Complexity

NASA Astrophysics Data System (ADS)

Czech, Bartłomiej

2018-01-01

A recent proposal equates the circuit complexity of a quantum gravity state with the gravitational action of a certain patch of spacetime. Since Einstein's equations follow from varying the action, it should be possible to derive them by varying complexity. I present such a derivation for vacuum solutions of pure Einstein gravity in three-dimensional asymptotically anti-de Sitter space. The argument relies on known facts about holography and on properties of tensor network renormalization, an algorithm for coarse-graining (and optimizing) tensor networks.

The effect of varying implant position in immediately loaded implant-supported mandibular overdentures.

PubMed

Shaarawy, Mohammed A; Aboelross, Ehab M

2013-06-01

This study was carried out to evaluate the effect of varying implant position in immediately loaded implant-supported mandibular overdentures on peri-implant bone density, muscle activity, and patient satisfaction. Fourteen completely edentulous patients were selected for the study. After complete denture construction, patients were divided into 2 equal groups. Four dental implants were installed bilaterally in the interforaminal region in the first group, while in the second group, 4 dental implants were inserted bilaterally: 2 in the interforaminal region and 2 in the first molar area. Immediately after suturing, telescopic abutments were screwed to the implants, and the retaining caps were picked up into the fitting surface of the lower denture, which was delivered to the patient. Patients were recalled for radiographic bone density evaluation just after denture delivery and then at 3, 6, and 12 months thereafter. Muscle activities of masseter and temporalis muscles as well as patient satisfaction were also evaluated. The results of the study showed a high success rate approximating 98.2% of the immediately loaded implants. The electromyographic (EMG) records of both muscles in group 1 were significantly higher during chewing hard food after 3 months compared with group 2 (P < .05). Bone density changes were comparable in the 2 groups except at the end of the follow-up period, when group 2 showed a significant increase in peri-implant bone density values of the posteriorly placed implants compared with group 1 (P < .05). From the results of this study, it may be concluded that wide distribution of immediately loaded implants used for supporting mandibular overdentures through posterior placement beyond the interforaminal area results in a favorable response in terms of increased peri-implant bone density as well as decreased EMG activity of masseter and temporalis muscles.

Fractal analysis of time varying data

DOEpatents

Vo-Dinh, Tuan; Sadana, Ajit

2002-01-01

Characteristics of time varying data, such as an electrical signal, are analyzed by converting the data from a temporal domain into a spatial domain pattern. Fractal analysis is performed on the spatial domain pattern, thereby producing a fractal dimension D.sub.F. The fractal dimension indicates the regularity of the time varying data.

Blood antimicrobial activity varies against different Mycobacterium spp.

PubMed

Rivero-Lezcano, Octavio Miguel; Blanco-Conde, Sara; López-Medrano, Ramiro; López-Fidalgo, Eduardo; Caño-Herrero, Manuela; Nebreda-Mayoral, Teresa

2017-12-01

In vitro analysis of mycobacterial pathogenicity or host susceptibility has traditionally relied on the infection of macrophages, the target cell of mycobacteria, despite difficulties reproducing their antimycobacterial activity. We have employed alternative models, namely whole blood and leukocytes in plasma, from QuantiFERON negative individuals, and performed infections with the pathogenic M. tuberculosis, the less pathogenic M. avium, M. kansasii and M. chelonae and the occasionally pathogenic M. gordonae and M. bovis. The anticoagulant used in blood extraction, heparin or EDTA, had a major influence in the outcome of the infection. Thus, while in the heparinized models a similar number of bacteria were enumerated in the inoculum and after seven days, in the presence of EDTA a killing effect was observed, despite the inhibitory effect of EDTA on cellular functions like the production of cytokines or reactive oxygen species (ROS). A special case was the rapidly growing mycobacteria M. chelonae, that multiplied in heparinized models but was eliminated in models with EDTA. We verified that EDTA is not responsible for the bactericidal effect, but acts as a bacteriostatic agent. Further work will determine whether blood derived models are a better alternative to the classical macrophage. Copyright © 2017 Elsevier Ltd. All rights reserved.

Optimization of Ligninolytic Enzyme Activity and Production Rate with Ceriporiopsis subvermispora for Application in Bioremediation by Varying Submerged Media Composition and Growth Immobilization Support

PubMed Central

Babič, Janja; Likozar, Blaž; Pavko, Aleksander

2012-01-01

Response surface methodology (central composite design of experiments) was employed to simultaneously optimize enzyme production and productivities of two ligninolytic enzymes produced by Ceriporiopsis subvermispora. Concentrations of glucose, ammonium tartrate and Polysorbate 80 were varied to establish the optimal composition of liquid media (OLM), where the highest experimentally obtained activities and productivities were 41 U L−1 and 16 U L−1 day−1 for laccase (Lac), and 193 U L−1 and 80 U L−1 day−1 for manganese peroxidase (MnP). Considering culture growth in OLM on various types of immobilization support, the best results were obtained with 1 cm beech wood cubes (BWCM). Enzyme activities in culture filtrate were 152 U L−1 for Lac and 58 U L−1 for MnP, since the chemical composition of this immobilization material induced higher Lac activity. Lower enzyme activities were obtained with polyurethane foam. Culture filtrates of OLM and BWCM were applied for dye decolorization. Remazol Brilliant Blue R (RBBR) was decolorized faster and more efficiently than Copper(II)phthalocyanine (CuP) with BWCM (80% and 60%), since Lac played a crucial role. Decolorization of CuP was initially faster than that of RBBR, due to higher MnP activities in OLM. The extent of decolorization after 14 h was 60% for both dyes. PMID:23109859

Routine activities and victimization at school: the significance of gender.

PubMed

Popp, Ann Marie; Peguero, Anthony A

2011-08-01

Routine activities theory has not fully considered the role of gender in shaping victimization and yet, the research literature clearly demonstrates that gender is associated with an individual's risk of victimization. In addition to the pervasive effect of gender on victimization, gender shapes an individual's daily routines and thus may create a gender-specific relationship with victimization. This article explores the importance of gender in understanding the relationship between student's participation in extracurricular routine activities (e.g., student government, clubs, sports, and etc.) and the risk of victimization. From the Education Longitudinal Study of 2002, a sample of 10th-grade students was drawn for analyses. Hierarchical Generalized Linear Modeling was employed to explore the role of gender in the relationship between extracurricular routine activities and victimization at school. The results reveal that students' gender indeed interacts with several of the extracurricular routine activities creating gender-specific risks of victimization. This article highlights the importance of gender in explaining victimization and suggests researchers should consider how gender may interact with other routine activities and victimization.

Performance improvement of ERP-based brain-computer interface via varied geometric patterns.

PubMed

Ma, Zheng; Qiu, Tianshuang

2017-12-01

Recently, many studies have been focusing on optimizing the stimulus of an event-related potential (ERP)-based brain-computer interface (BCI). However, little is known about the effectiveness when increasing the stimulus unpredictability. We investigated a new stimulus type of varied geometric pattern where both complexity and unpredictability of the stimulus are increased. The proposed and classical paradigms were compared in within-subject experiments with 16 healthy participants. Results showed that the BCI performance was significantly improved for the proposed paradigm, with an average online written symbol rate increasing by 138% comparing with that of the classical paradigm. Amplitudes of primary ERP components, such as N1, P2a, P2b, N2, were also found to be significantly enhanced with the proposed paradigm. In this paper, a novel ERP BCI paradigm with a new stimulus type of varied geometric pattern is proposed. By jointly increasing the complexity and unpredictability of the stimulus, the performance of an ERP BCI could be considerably improved.

Estimating time-varying conditional correlations between stock and foreign exchange markets

NASA Astrophysics Data System (ADS)

Tastan, Hüseyin

2006-02-01

This study explores the dynamic interaction between stock market returns and changes in nominal exchange rates. Many financial variables are known to exhibit fat tails and autoregressive variance structure. It is well-known that unconditional covariance and correlation coefficients also vary significantly over time and multivariate generalized autoregressive model (MGARCH) is able to capture the time-varying variance-covariance matrix for stock market returns and changes in exchange rates. The model is applied to daily Euro-Dollar exchange rates and two stock market indexes from the US economy: Dow-Jones Industrial Average Index and S&P500 Index. The news impact surfaces are also drawn based on the model estimates to see the effects of idiosyncratic shocks in respective markets.

Measuring the Impact of Varied Instructional Approaches in an Introductory Animal Science Course

ERIC Educational Resources Information Center

Bolt, Brian Grady

2009-01-01

The objectives of this project were to: evaluate the impact of demographic descriptors (gender, class rank and final grade) on student's self perceived level of engagement in classroom activities; measure the impact of varying teaching styles on a student's likelihood of correctly answering a knowledge based question and: assessing the…

The home physical activity environment and adolescent BMI, physical activity and TV viewing: Disparities across a diverse sample

PubMed Central

Larson, Nicole I.; Berge, Jerica M.; Thul, Chelsey; Neumark-Sztainer, Dianne

2014-01-01

Objective Characteristics of the home and family have been associated with adolescents' BMI and physical and sedentary activity, but few studies have examined how these characteristics vary across ethnic/racial groups. This study explores whether recommendations for activity promotion are equally relevant to different adolescent populations. Design Participants included 2,374 adolescents and their parent(s), recruited through 20 public schools in Minneapolis/St. Paul, MN in 2009-2010. Ethnic/racial groups included African American, Asian (primarily Hmong), East African, Hispanic, Native American, White, and mixed/other race. Linear regression analysis modeled adolescents' BMI z-scores and physical and sedentary activity based on six measures of the family/home activity environment, adjusted for covariates. Interactions of ethnicity/race and family/home environment were tested. Results All six family/home environment measures varied significantly across ethnicity/race. Family/home variables were significantly associated with adolescent physical activity and TV viewing in the expected directions, and these relationships were consistent across ethnic/racial groups in two-thirds of the models. However, in one-third of the cases, these associations were modified by ethnicity/race. For example, home access to a greater number of media devices was significantly associated with more TV viewing (β=.40, p=.015) only among White youth. Conclusion Health promotion recommendations for adolescent physical activity are largely relevant across ethnic/racial groups. However, given differences found in the family/home environments of adolescents, cultural sensitivity is recommended in discussing these issues, and tailored recommendations may be appropriate for select groups or behaviors. Further mixed methods research is warranted to help identify key messages for specific groups. PMID:25396114

Multiple μ-stability of neural networks with unbounded time-varying delays.

PubMed

Wang, Lili; Chen, Tianping

2014-05-01

In this paper, we are concerned with a class of recurrent neural networks with unbounded time-varying delays. Based on the geometrical configuration of activation functions, the phase space R(n) can be divided into several Φη-type subsets. Accordingly, a new set of regions Ωη are proposed, and rigorous mathematical analysis is provided to derive the existence of equilibrium point and its local μ-stability in each Ωη. It concludes that the n-dimensional neural networks can exhibit at least 3(n) equilibrium points and 2(n) of them are μ-stable. Furthermore, due to the compatible property, a set of new conditions are presented to address the dynamics in the remaining 3(n)-2(n) subset regions. As direct applications of these results, we can get some criteria on the multiple exponential stability, multiple power stability, multiple log-stability, multiple log-log-stability and so on. In addition, the approach and results can also be extended to the neural networks with K-level nonlinear activation functions and unbounded time-varying delays, in which there can store (2K+1)(n) equilibrium points, (K+1)(n) of them are locally μ-stable. Numerical examples are given to illustrate the effectiveness of our results. Copyright © 2014 Elsevier Ltd. All rights reserved.

Clinical significance of neonatal menstruation.

PubMed

Brosens, Ivo; Benagiano, Giuseppe

2016-01-01

Past studies have clearly shown the existence of a spectrum of endometrial progesterone responses in neonatal endometrium, varying from proliferation to full decidualization with menstrual-like shedding. The bleedings represent, similar to what occurs in adult menstruation, a progesterone withdrawal bleeding. Today, the bleeding is completely neglected and considered an uneventful episode of no clinical significance. Yet clinical studies have linked the risk of bleeding to a series of events indicating fetal distress. The potential link between the progesterone response and major adolescent disorders requires to be investigated by prospective studies. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Functional significance of the intermediate conductance Ca2+-activated K+ channel for the short-term survival of injured erythrocytes.

PubMed

Föller, Michael; Bobbala, Diwakar; Koka, Saisudha; Boini, Krishna M; Mahmud, Hasan; Kasinathan, Ravi S; Shumilina, Ekaterina; Amann, Kerstin; Beranek, Golo; Sausbier, Ulrike; Ruth, Peter; Sausbier, Matthias; Lang, Florian; Huber, Stephan M

2010-11-01

Increased cytosolic Ca(2+) concentrations activate Gardos K(+) channels in human erythrocytes with membrane hyperpolarization, efflux of K(+), Cl⁻, and osmotically obliged H₂O resulting in cell shrinkage, a phenomenon referred to as Gardos effect. We tested whether the Gardos effect delays colloid osmotic hemolysis of injured erythrocytes from mice lacking the Ca(2+)-activated K(+) channel K(Ca)3.1. To this end, we applied patch clamp and flow cytometry and determined in vitro as well as in vivo hemolysis. As a result, erythrocytes from K(Ca)3.1-deficient (K(Ca)3.1(-/-)) mice lacked Gardos channel activity and the Gardos effect. Blood parameters, reticulocyte count, or osmotic erythrocyte resistance, however, did not differ between K(Ca)3.1(-/-) mice and their wild-type littermates, suggesting low or absent Gardos channel activity in unstressed erythrocytes. Oxidative stress-induced Ca(2+) entry and phospholipid scrambling were significantly less pronounced in K(Ca)3.1(-/-) than in wild-type erythrocytes. Moreover, in vitro treatment with α-toxin from Staphylococcus aureus, which forms pores in the cellular membrane, resulted in significantly stronger hemolysis of K(Ca)3.1(-/-) than of wild-type erythrocytes. Intravenous injection of α-toxin induced more profound hemolysis in K(Ca)3.1(-/-) than in wild-type mice. Similarly, intra-peritoneal application of the redox-active substance phenylhydrazine, an agent for the induction of hemolytic anemia, was followed by a significantly stronger decrease of hematocrit in K(Ca)3.1(-/-) than in wild-type mice. Finally, malaria infection triggered the activation of K(Ca)3.1 and transient shrinkage of the infected erythrocytes. In conclusion, K(Ca)3.1 channel activity and Gardos effect counteract hemolysis of injured erythrocytes, thus decreasing hemoglobin release into circulating blood.

The biological significance of color constancy: an agent-based model with bees foraging from flowers under varied illumination.

PubMed

Faruq, Samia; McOwan, Peter W; Chittka, Lars

2013-08-20

The perceived color of an object depends on its spectral reflectance and the spectral composition of the illuminant. Thus when the illumination changes, the light reflected from the object also varies. This would result in a different color sensation if no color constancy mechanism is put in place-that is, the ability to form consistent representation of colors across various illuminants and background scenes. We explore the quantitative benefits of various color constancy algorithms in an agent-based model of foraging bees, where agents select flower color based on reward. Each simulation is based on 100 "meadows" with five randomly selected flower species with empirically determined spectral reflectance properties, and each flower species is associated with realistic distributions of nectar rewards. Simulated foraging bees memorize the colors of flowers that they have experienced as most rewarding, and their task is to discriminate against other flower colors with lower rewards, even in the face of changing illumination conditions. We compared the performance of von Kries, White Patch, and Gray World constancy models with (hypothetical) bees with perfect color constancy, and color-blind bees. A bee equipped with trichromatic color vision but no color constancy performed only ∼20% better than a color-blind bee (relative to a maximum improvement at 100% for perfect color constancy), whereas the most powerful recovery of reflectance in the face of changing illumination was generated by a combination of von Kries photoreceptor adaptation and a White Patch calibration (∼30% improvement relative to a bee without color constancy). However, none of the tested algorithms generated perfect color constancy.

At-sea behavior varies with lunar phase in a nocturnal pelagic seabird, the swallow-tailed gull

USGS Publications Warehouse

Cruz, Sebastian M.; Hooten, Mevin; Huyvaert, Kathryn P.; Proaño, Carolina B.; Anderson, David J.; Afanasyev, Vsevolod; Wikelski, Martin

2013-01-01

Strong and predictable environmental variability can reward flexible behaviors among animals. We used long-term records of activity data that cover several lunar cycles to investigate whether behavior at-sea of swallow-tailed gulls Creagrus furcatus, a nocturnal pelagic seabird, varied with lunar phase in the Galápagos Islands. A Bayesian hierarchical model showed that nighttime at-sea activity of 37 breeding swallow-tailed gulls was clearly associated with changes in moon phase. Proportion of nighttime spent on water was highest during darker periods of the lunar cycle, coinciding with the cycle of the diel vertical migration (DVM) that brings prey to the sea surface at night. Our data show that at-sea behavior of a tropical seabird can vary with environmental changes, including lunar phase.

At-sea behavior varies with lunar phase in a nocturnal pelagic seabird, the swallow-tailed gull.

PubMed

Cruz, Sebastian M; Hooten, Mevin; Huyvaert, Kathryn P; Proaño, Carolina B; Anderson, David J; Afanasyev, Vsevolod; Wikelski, Martin

2013-01-01

Strong and predictable environmental variability can reward flexible behaviors among animals. We used long-term records of activity data that cover several lunar cycles to investigate whether behavior at-sea of swallow-tailed gulls Creagrus furcatus, a nocturnal pelagic seabird, varied with lunar phase in the Galápagos Islands. A Bayesian hierarchical model showed that nighttime at-sea activity of 37 breeding swallow-tailed gulls was clearly associated with changes in moon phase. Proportion of nighttime spent on water was highest during darker periods of the lunar cycle, coinciding with the cycle of the diel vertical migration (DVM) that brings prey to the sea surface at night. Our data show that at-sea behavior of a tropical seabird can vary with environmental changes, including lunar phase.

Trapezius muscle activity increases during near work activity regardless of accommodation/vergence demand level.

PubMed

Richter, H O; Zetterberg, C; Forsman, M

2015-07-01

To investigate if trapezius muscle activity increases over time during visually demanding near work. The vision task consisted of sustained focusing on a contrast-varying black and white Gabor grating. Sixty-six participants with a median age of 38 (range 19-47) fixated the grating from a distance of 65 cm (1.5 D) during four counterbalanced 7-min periods: binocularly through -3.5 D lenses, and monocularly through -3.5 D, 0 D and +3.5 D. Accommodation, heart rate variability and trapezius muscle activity were recorded in parallel. General estimating equation analyses showed that trapezius muscle activity increased significantly over time in all four lens conditions. A concurrent effect of accommodation response on trapezius muscle activity was observed with the minus lenses irrespective of whether incongruence between accommodation and convergence was present or not. Trapezius muscle activity increased significantly over time during the near work task. The increase in muscle activity over time may be caused by an increased need of mental effort and visual attention to maintain performance during the visual tasks to counteract mental fatigue.

Walking with a four wheeled walker (rollator) significantly reduces EMG lower-limb muscle activity in healthy subjects.

PubMed

Suica, Zorica; Romkes, Jacqueline; Tal, Amir; Maguire, Clare

2016-01-01

To investigate the immediate effect of four-wheeled- walker(rollator)walking on lower-limb muscle activity and trunk-sway in healthy subjects. In this cross-sectional design electromyographic (EMG) data was collected in six lower-limb muscle groups and trunk-sway was measured as peak-to-peak angular displacement of the centre-of-mass (level L2/3) in the sagittal and frontal-planes using the SwayStar balance system. 19 subjects walked at self-selected speed firstly without a rollator then in randomised order 1. with rollator 2. with rollator with increased weight-bearing. Rollator-walking caused statistically significant reductions in EMG activity in lower-limb muscle groups and effect-sizes were medium to large. Increased weight-bearing increased the effect. Trunk-sway in the sagittal and frontal-planes showed no statistically significant difference between conditions. Rollator-walking reduces lower-limb muscle activity but trunk-sway remains unchanged as stability is likely gained through forces generated by the upper-limbs. Short-term stability is gained but the long-term effect is unclear and requires investigation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Weather is not significantly correlated with destination-specific transport-related physical activity among adults: A large-scale temporally matched analysis.

PubMed

Durand, Casey P; Zhang, Kai; Salvo, Deborah

2017-08-01

Weather is an element of the natural environment that could have a significant effect on physical activity. Existing research, however, indicates only modest correlations between measures of weather and physical activity. This prior work has been limited by a failure to use time-matched weather and physical activity data, or has not adequately examined the different domains of physical activity (transport, leisure, occupational, etc.). Our objective was to identify the correlation between weather variables and destination-specific transport-related physical activity in adults. Data were sourced from the California Household Travel Survey, collected in 2012-3. Weather variables included: relative humidity, temperature, wind speed, and precipitation. Transport-related physical activity (walking) was sourced from participant-recorded travel diaries. Three-part hurdle models were used to analyze the data. Results indicate statistically or substantively insignificant correlations between the weather variables and transport-related physical activity for all destination types. These results provide the strongest evidence to date that transport-related physical activity may occur relatively independently of weather conditions. The knowledge that weather conditions do not seem to be a significant barrier to this domain of activity may potentially expand the universe of geographic locations that are amenable to environmental and programmatic interventions to increase transport-related walking. Copyright © 2017 Elsevier Inc. All rights reserved.

[Functional significance of high-frequency components of brain electrical activity in the processes of gestalt formation].

PubMed

Dumenko, V N

2002-01-01

A review. Current views of the so-called binding problem, which considers hypothetical mechanisms of perception of sensory stimuli and formation of their corresponding Gestalts (internal images) are discussed. The mechanism of intensification of synchronized reactions of cortical electrical activity in the gamma band frequency (30-80 Hz) is the basis of the most popular point of view of "binding". The article considers the evidence for the functional significance of the high-frequency components exceeding the gamma-range (to 200 Hz) obtained by the author, the origin of these oscillations, and conditions of their focal derivation. The problem of "binding" and stages of instrumental conditioning (a stimulus, perception of the stimulus, and its transformation into a signal) as well as significance of the context in learning and formation of tonic states ensuring the realization of phasic reactions is discussed. Forms of "binding" at the final stage of conditioning (selective attention) are considered. The question is posed as to whether "binding" is exhausted only by the mechanisms of synchronization of activities of large neuronal populations and only in the frequencies of the gamma range.

The Effect of Varying Biting Position on Relative Jaw Muscle EMG activity

DTIC Science & Technology

1988-09-01

with muscle force is the key to 13 this approach as it allows inference of muscle contraction activity from EMG data. This relationship has been the...5! 15 LITERATURE REVIEW Introduction: The study of the physiology of bite force, muscle contraction force, joint reaction force and the lever system...Currently, the best method of indirectly observing muscle contraction activity is through electromyography. Although there appears to be a time delay

A novel indirect method for capturing involuntary musical imagery under varying cognitive load.

PubMed

Floridou, Georgia A; Williamson, Victoria J; Stewart, Lauren

2017-11-01

Involuntary musical imagery (INMI), i.e the internal experience of a repetitive musical fragment, is one of the most ubiquitous forms of spontaneous cognition. Findings regarding the relationship between INMI and cognitive load are conflicting. In the present study, 200 participants watched and evaluated two non-dialogue, music-only film trailers. Subsequently, they either closed their eyes for 5 min (baseline), or engaged in one of three dot tasks of varying challenge and attentional demand (low, medium, and high cognitive load). Finally, they completed a novel "Mind Activity Questionnaire", which allows for indirect INMI sampling rather than direct questioning. The same questionnaire was completed 24 hours later. Overall, a significant negative linear trend was found. At baseline, 65% of people reported experiencing INMI. This rate decreased to 32.5% in the low load condition with further reductions observed in the medium and high conditions, which did not differ significantly from each other. INMI frequency and duration followed the same pattern as the induction rates. In the 24-hour follow-up, 21% of participants reported INMI experiences. This study supports the hypothesis that INMI occurrence, frequency, and duration relate to spare cognitive capacity and demonstrates an ecologically valid laboratory paradigm for covertly inducing and documenting INMI experiences.

Design of 2D time-varying vector fields.

PubMed

Chen, Guoning; Kwatra, Vivek; Wei, Li-Yi; Hansen, Charles D; Zhang, Eugene

2012-10-01

Design of time-varying vector fields, i.e., vector fields that can change over time, has a wide variety of important applications in computer graphics. Existing vector field design techniques do not address time-varying vector fields. In this paper, we present a framework for the design of time-varying vector fields, both for planar domains as well as manifold surfaces. Our system supports the creation and modification of various time-varying vector fields with desired spatial and temporal characteristics through several design metaphors, including streamlines, pathlines, singularity paths, and bifurcations. These design metaphors are integrated into an element-based design to generate the time-varying vector fields via a sequence of basis field summations or spatial constrained optimizations at the sampled times. The key-frame design and field deformation are also introduced to support other user design scenarios. Accordingly, a spatial-temporal constrained optimization and the time-varying transformation are employed to generate the desired fields for these two design scenarios, respectively. We apply the time-varying vector fields generated using our design system to a number of important computer graphics applications that require controllable dynamic effects, such as evolving surface appearance, dynamic scene design, steerable crowd movement, and painterly animation. Many of these are difficult or impossible to achieve via prior simulation-based methods. In these applications, the time-varying vector fields have been applied as either orientation fields or advection fields to control the instantaneous appearance or evolving trajectories of the dynamic effects.

Robust state estimation for uncertain fuzzy bidirectional associative memory networks with time-varying delays

NASA Astrophysics Data System (ADS)

Vadivel, P.; Sakthivel, R.; Mathiyalagan, K.; Arunkumar, A.

2013-09-01

This paper addresses the issue of robust state estimation for a class of fuzzy bidirectional associative memory (BAM) neural networks with time-varying delays and parameter uncertainties. By constructing the Lyapunov-Krasovskii functional, which contains the triple-integral term and using the free-weighting matrix technique, a set of sufficient conditions are derived in terms of linear matrix inequalities (LMIs) to estimate the neuron states through available output measurements such that the dynamics of the estimation error system is robustly asymptotically stable. In particular, we consider a generalized activation function in which the traditional assumptions on the boundedness, monotony and differentiability of the activation functions are removed. More precisely, the design of the state estimator for such BAM neural networks can be obtained by solving some LMIs, which are dependent on the size of the time derivative of the time-varying delays. Finally, a numerical example with simulation result is given to illustrate the obtained theoretical results.

Time-varying wall stress: an index of ventricular vascular coupling.

PubMed

Dell'Italia, L J; Blackwell, G G; Thorn, B T; Pearce, D J; Bishop, S P; Pohost, G M

1992-08-01

Previous work in the isolated heart and intact circulation has suggested that the relationship between wall stress and time during left ventricular (LV) ejection is linear and that the slope, which will be referred to as time-varying wall stress, increases in response to augmentation in afterload. However, the etiology of the increase in slope has not been determined in an intact animal. Magnetic resonance imaging coupled with high-fidelity LV pressure measurement using a nonferrous catheter-tip manometer generates a detailed assessment of wall stress in an animal model where the thorax and pericardium have never been disturbed. Accordingly, six anesthetized dogs were studied during autonomic blockade with atropine and propranolol during angiotensin infusion, producing three widely disparate left ventricular systolic pressures (87 +/- 7 vs. 124 +/- 13 vs. 152 +/- 10 mmHg, P less than 0.001). Time-varying wall stress did not change from low to medium load (-42.4 +/- 9.5 to -27.3 +/- 22.3 g.cm-2.ms-1) but increased significantly at high load (-21.7 +/- 14.9 g.cm-2.ms-1, P less than 0.05). Analysis of the relative contribution of pressure, chamber radius, wall thickness, and long-axis dimension to the changes in time-varying wall stress demonstrated only the pressure component to change its relative contribution at medium (P less than 0.001) and high load (P less than 0.001). Therefore, we conclude that the increase in time-varying wall stress results from augmentation of pressure in the latter one-half of systole that is incompletely offset by shortening and wall thickening.(ABSTRACT TRUNCATED AT 250 WORDS)

Piezoceramic devices and artificial intelligence time varying concepts in smart structures

NASA Technical Reports Server (NTRS)

Hanagud, S.; Calise, A. J.; Glass, B. J.

1990-01-01

The problem of development of smart structures and their vibration control by the use of piezoceramic sensors and actuators have been discussed. In particular, these structures are assumed to have time varying model form and parameters. The model form may change significantly and suddenly. Combined identification of the model from parameters of these structures and model adaptive control of these structures are discussed in this paper.

Weekday and weekend sedentary time and physical activity in differentially active children.

PubMed

Fairclough, Stuart J; Boddy, Lynne M; Mackintosh, Kelly A; Valencia-Peris, Alexandra; Ramirez-Rico, Elena

2015-07-01

To investigate whether weekday-weekend differences in sedentary time and specific intensities of physical activity exist among children categorised by physical activity levels. Cross-sectional observational study. Seven-day accelerometer data were obtained from 810 English children (n=420 girls) aged 10-11 years. Daily average minday(-1) spent in moderate to vigorous physical activity were calculated for each child. Sex-specific moderate to vigorous physical activity quartile cut-off values categorised boys and girls separately into four graded groups representing the least (Q1) through to the most active (Q4) children. Sex- and activity quartile-specific multilevel linear regression analyses analysed differences in sedentary time, light physical activity, moderate physical activity, vigorous physical activity, and moderate to vigorous physical activity between weekdays and weekends. On weekdays Q2 boys spent longer in light physical activity (p<0.05), Q1 (p<0.001), Q2 boys (p<0.01) did significantly more moderate physical activity, and Q1-Q3 boys accumulated significantly more vigorous physical activity and moderate to vigorous physical activity than at weekends. There were no significant differences in weekday and weekend sedentary time or physical activity for Q4 boys. On weekdays Q2 and Q3 girls accumulated more sedentary time (p<0.05), Q1 and Q2 girls did significantly more moderate physical activity (p<0.05), and Q1-Q3 girls engaged in more vigorous physical activity (p<0.05) and more moderate to vigorous physical activity (p<0.01) than at weekends. Q4 girls' sedentary time and physical activity varied little between weekdays and weekends. The most active children maintained their sedentary time and physical activity levels at weekends, while among less active peers weekend sedentary time and physical activity at all intensities was lower. Low active children may benefit most from weekend intervention strategies. Copyright © 2014 Sports Medicine Australia

Stability in Cohen Grossberg-type bidirectional associative memory neural networks with time-varying delays

NASA Astrophysics Data System (ADS)

Cao, Jinde; Song, Qiankun

2006-07-01

In this paper, the exponential stability problem is investigated for a class of Cohen-Grossberg-type bidirectional associative memory neural networks with time-varying delays. By using the analysis method, inequality technique and the properties of an M-matrix, several novel sufficient conditions ensuring the existence, uniqueness and global exponential stability of the equilibrium point are derived. Moreover, the exponential convergence rate is estimated. The obtained results are less restrictive than those given in the earlier literature, and the boundedness and differentiability of the activation functions and differentiability of the time-varying delays are removed. Two examples with their simulations are given to show the effectiveness of the obtained results.

Significance of platelet-activating factor acetylhydrolase in patients with non-insulin-dependent (type 2) diabetes mellitus.

PubMed

Serban, M; Tanaseanu, Cristina; Kosaka, T; Vidulescu, Cristina; Stoian, Irina; Marta, Daciana S; Tanaseanu, S; Moldoveanu, Elena

2002-01-01

Non-insulin dependent diabetes mellitus (NIDDM) represents an independent risk factor for cardiovascular diseases (CVD), being characterized by a continuous low-grade inflammation and endothelial activation state. Plasma platelet - activating factor - acetylhydrolases (PAF-AHs) are a subgroup of Ca(2+)-independent phospholipase A(2) family (also known as lipoprotein-associated phospholipases A(2)) that hydrolyze and inactivate the lipid mediator platelet-activating factor (PAF) and/or oxidized phospholipids. This enzyme is considered to play an important role in inflammatory diseases and atherosclerosis. The present study aims to investigate the relations between the levels of PAF-AH activity and LDL-cholesterol / HDL-cholesterol (LDL-ch / HDL-ch) ratio in NIDDM patients as compared to controls. serum PAF-AH activity was measured in 50 patients with dyslipidemia, in 50 NIDDM patients and in 50 controls (normal lipid and glucose levels). Total cholesterol, LDL-ch, HDL-ch, triglyceride and blood glucose were determined in all subjects. All NIDDM patients display hiperlipidemia, with increased LDL-ch and triglyceride levels. There is a significant correlation between LDL-ch levels (especially LDL-ch / HDL-ch ratio) and PAF-AH activity in dyslipidemic and NIDDM patients. Diabetic and dyslipidemic patients have an increased plasma PAF-AH activity correlated with their LDL-ch levels and mainly with LDL-ch / HDL-ch ratio. Plasma PAF-AH high levels appear to be important as a risk marker for endothelial dysfunction in patients with NIDDM.

Renormalization group theory for percolation in time-varying networks.

PubMed

Karschau, Jens; Zimmerling, Marco; Friedrich, Benjamin M

2018-05-22

Motivated by multi-hop communication in unreliable wireless networks, we present a percolation theory for time-varying networks. We develop a renormalization group theory for a prototypical network on a regular grid, where individual links switch stochastically between active and inactive states. The question whether a given source node can communicate with a destination node along paths of active links is equivalent to a percolation problem. Our theory maps the temporal existence of multi-hop paths on an effective two-state Markov process. We show analytically how this Markov process converges towards a memoryless Bernoulli process as the hop distance between source and destination node increases. Our work extends classical percolation theory to the dynamic case and elucidates temporal correlations of message losses. Quantification of temporal correlations has implications for the design of wireless communication and control protocols, e.g. in cyber-physical systems such as self-organized swarms of drones or smart traffic networks.

Time varying voltage combustion control and diagnostics sensor

DOEpatents

Chorpening, Benjamin T [Morgantown, WV; Thornton, Jimmy D [Morgantown, WV; Huckaby, E David [Morgantown, WV; Fincham, William [Fairmont, WV

2011-04-19

A time-varying voltage is applied to an electrode, or a pair of electrodes, of a sensor installed in a fuel nozzle disposed adjacent the combustion zone of a continuous combustion system, such as of the gas turbine engine type. The time-varying voltage induces a time-varying current in the flame which is measured and used to determine flame capacitance using AC electrical circuit analysis. Flame capacitance is used to accurately determine the position of the flame from the sensor and the fuel/air ratio. The fuel and/or air flow rate (s) is/are then adjusted to provide reduced flame instability problems such as flashback, combustion dynamics and lean blowout, as well as reduced emissions. The time-varying voltage may be an alternating voltage and the time-varying current may be an alternating current.

Novel shock absorber features varying yield strengths

NASA Technical Reports Server (NTRS)

Geier, D. J.

1964-01-01

A shock absorbent webbing of partially drawn synthetic strands is arranged in sections of varying density related to the varying mass of the human body. This is contoured to protect the body at points of contact, when subjected to large acceleration or deceleration forces.

Differences in associations between active transportation and built environmental exposures when expressed using different components of individual activity spaces.

PubMed

van Heeswijck, Torbjorn; Paquet, Catherine; Kestens, Yan; Thierry, Benoit; Morency, Catherine; Daniel, Mark

2015-05-01

This study assessed relationships between built environmental exposures measured within components of individual activity spaces (i.e., travel origins, destinations and paths in-between), and use of active transportation in a metropolitan setting. Individuals (n=37,165) were categorised as using active or sedentary transportation based on travel survey data. Generalised Estimating Equations analysis was used to test relationships with active transportation. Strength and significance of relationships between exposures and active transportation varied for different components of the activity space. Associations were strongest when including travel paths in expression of the built environment. Land use mix and greenness were negatively related to active transportation. Copyright © 2015 Elsevier Ltd. All rights reserved.

At–Sea Behavior Varies with Lunar Phase in a Nocturnal Pelagic Seabird, the Swallow-Tailed Gull

PubMed Central

Cruz, Sebastian M.; Hooten, Mevin; Huyvaert, Kathryn P.; Proaño, Carolina B.; Anderson, David J.; Afanasyev, Vsevolod; Wikelski, Martin

2013-01-01

Strong and predictable environmental variability can reward flexible behaviors among animals. We used long-term records of activity data that cover several lunar cycles to investigate whether behavior at-sea of swallow-tailed gulls Creagrus furcatus, a nocturnal pelagic seabird, varied with lunar phase in the Galápagos Islands. A Bayesian hierarchical model showed that nighttime at-sea activity of 37 breeding swallow-tailed gulls was clearly associated with changes in moon phase. Proportion of nighttime spent on water was highest during darker periods of the lunar cycle, coinciding with the cycle of the diel vertical migration (DVM) that brings prey to the sea surface at night. Our data show that at-sea behavior of a tropical seabird can vary with environmental changes, including lunar phase. PMID:23468889

High aryl acylamidase activity associated with cobra venom acetylcholinesterase: biological significance.

PubMed

Rajesh, Ramanna V; Layer, Paul G; Boopathy, Rathanam

2009-01-01

Investigation of the non-classical functions of cholinesterases (ChEs) has been the subject of interest in the past three decades. One of which is aryl acylamidase (AAA) activity associated with ChEs, but characterized in in vitro, as an enzyme, splitting the artificial substrate o-nitroacetanilide with unknown physiological function. In the present study, we have compared levels of AAA activity of AChE from different sources like goat brain, electric eel organ and from venoms of different snakes. Remarkably cobra venom showed the highest AAA activity and also high AAA/AChE ratio. Both serotonergenic and cholinergic inhibitors inhibited the cobra venom AAA activity in a concentration dependent manner, which also underlines the association of AAA with AChE of cobra venom. The study becomes interesting because of i) the cobra venom AChE exists in monomeric globular forms; ii) in Alzheimer's disease too the most abundant forms of cholinesterases are monomeric globular forms, thought to be involved in the pathogenesis of Alzheimer's disease; iii) the effect of Alzheimer's disease drugs on the AAA activity of cobra venom, indicated that AAA activity of cobra venom was more sensitive than AChE and iv) Huperzine and Tacrine showed more pronounced effect on AAA. Thus, this study elucidates the high AAA associated with cobra venom AChE may serve as one of the prominent activity to test the pharmacological effect of AD drugs, as other sources were found to have lower activity.

Mutagenesis of a bacteriophage lytic enzyme PlyGBS significantly increases its antibacterial activity against group B streptococci.

PubMed

Cheng, Qi; Fischetti, Vincent A

2007-04-01

Group B streptococci (GBS) are the leading cause of neonatal meningitis and sepsis worldwide. Intrapartum antibiotic prophylaxis (IAP) is the current prevention strategy given to pregnant women with confirmed vaginal GBS colonization. Due to antibiotic resistance identified in GBS, we previously developed another strategy using a bacteriophage lytic enzyme, PlyGBS, to reduce vaginal GBS colonization. In this study, various DNA mutagenesis methods were explored to produce PlyGBS mutants with increased lytic activity against GBS. Several hyperactive mutants were identified that contain only the endopeptidase domain found in the N-terminal region of PlyGBS and represent only about one-third of the wild-type PlyGBS in length. Significantly, these mutants not only have 18-28-fold increases in specific activities compared to PlyGBS, but they also have a similar activity spectrum against several streptococcal species. One of the hyperactive mutants, PlyGBS90-1, reduced the GBS colonization from >5 logs of growth per mouse to <50 colony-forming units (cfu) 4 h post treatment ( approximately 4-log reduction) using a single dose in a mouse vaginal model. A reduction in GBS colonization before delivery should significantly reduce neonatal GBS infection providing a safe alternative to IAP.

Correlation between Serum Calcineurin Activity and Left Ventricular Hypertrophy in Hypertensive Patients and Its Clinical Significance.

PubMed

Cao, Jia-Li; Yang, Yu-Qing; Nabeel, Dookhun Muhammad; Sun, Ya-Li; Zou, Hua-Yi-Yang; Kong, Xiang-Qing; Lu, Xin-Zheng

The aim of this study is to investigate the correlation between calcineurin (CaN) and hypertension with left ventricular hypertrophy (HLVH) and to evaluate its potential clinical significance. The study involved 160 patients diagnosed with hypertension and 42 controls. Based on the exclusion criteria, 42 were not eligible for this study. The remaining 118 hypertensive patients were categorized into 2 subgroups based on left ventricular mass index and relative ventricular wall thickness: a normal model subgroup with hypertension (HNM) and an HLVH subgroup. Serum CaN levels were determined by enzyme-linked immunosorbent assay, while serum CaN activity was determined by malachite green colorimetric assay. Among the HNM and HLVH subgroups, a positive correlation was demonstrated between serum CaN activity, but not serum CaN level, and HLVH. Moreover, the HLVH subgroup displayed a remarkable increase in the levels of brain natriuretic peptide, cystatin C, urinary albumin/creatinine ratio, and left atrium diameter compared to the HNM subgroup and controls. There was a positive correlation between serum CaN activity and LVH in hypertensive patients. Activated CaN could play an important role in the pathophysiologic mechanism of HLVH. Serum CaN activity could be a clinically useful diagnostic and prognostic biomarker for LVH. © 2018 S. Karger AG, Basel.

Physical Activity Participation and Nutrition and Physical Activity Knowledge in University Dance Students.

PubMed

Hanna, Katherine; Hanley, Anne; Huddy, Avril; McDonald, Michael; Willer, Fiona

2017-03-01

To assess participation in physical activity and knowledge of general nutrition and current public health messages about the health benefits of physical activity in university dance students, and to investigate differences between first-year and later-year students and between students in dance and dance performance course groups. This cross-sectional study recruited 67 participants from dance undergraduate degrees in a university in Australia. Nutrition knowledge was assessed using the General Nutrition Knowledge Questionnaire. Physical activity participation and awareness of its benefits were assessed using the Active Australia Survey. Results indicate low nutrition knowledge among dance students, with 47% and 52% of responses correct in dance and dance performance students, respectively. Nutrition knowledge did not vary between students in first or later years. Self-reported participation in moderate and vigorous physical activity varied substantially and met or exceeded recommendations based upon duration and frequency for 98% of participants. However, awareness of physical activity messages varied, with dance students more likely to disagree about the level of activity needed for health benefits. Dance students report varying levels of physical activity that usually met or exceeded recommendations; however, knowledge of general nutrition and physical activity benefits was low. Improved knowledge could contribute to changes in behavior that improve health status in this population.

Understanding the disparity: predictors of virologic failure in women using highly active antiretroviral therapy vary by race and/or ethnicity.

PubMed

McFall, Allison M; Dowdy, David W; Zelaya, Carla E; Murphy, Kerry; Wilson, Tracey E; Young, Mary A; Gandhi, Monica; Cohen, Mardge H; Golub, Elizabeth T; Althoff, Keri N

2013-11-01

Stark racial/ethnic disparities in health outcomes exist among those living with HIV in the United States. One of 3 primary goals of the National HIV/AIDS Strategy is to reduce HIV-related disparities and health inequities. Using data from HIV-infected women participating in the Women's Interagency HIV Study from April 2006 to March 2011, we measured virologic failure (HIV RNA >200 copies/mL) after suppression (HIV RNA < 80 copies/mL) on highly active antiretroviral therapy. We identified predictors of virologic failure using discrete time survival analysis and calculated racial/ethnic-specific population-attributable fractions (PAFs). Of 887 eligible women, 408 (46%) experienced virologic failure during the study period. Hispanic and white women had significantly lower hazards of virologic failure than African American women [Hispanic hazard ratio, (HR) = 0.8, 95% confidence interval: (0.6 to 0.9); white HR = 0.7 (0.5 to 0.9)]. The PAF of virologic failure associated with low income was higher in Hispanic [adjusted hazard ratios (aHR) = 2.2 (0.7 to 6.5), PAF = 49%] and African American women [aHR = 1.8 (1.1 to 3.2), PAF = 38%] than among white women [aHR = 1.4 (0.6 to 3.4), PAF = 16%]. Lack of health insurance compared with public health insurance was associated with virologic failure only among Hispanic [aHR = 2.0 (0.9 to 4.6), PAF = 22%] and white women [aHR = 1.9 (0.7 to 5.1), PAF = 13%]. By contrast, depressive symptoms were associated with virologic failure only among African-American women [aHR = 1.6 (1.2 to 2.2), PAF = 17%]. In this population of treated HIV-infected women, virologic failure was common, and correlates of virologic failure varied by race/ethnicity. Strategies to reduce disparities in HIV treatment outcomes by race/ethnicity should address racial/ethnic-specific barriers including depression and low income to sustain virologic suppression.

Estimating varying coefficients for partial differential equation models.

PubMed

Zhang, Xinyu; Cao, Jiguo; Carroll, Raymond J

2017-09-01

Partial differential equations (PDEs) are used to model complex dynamical systems in multiple dimensions, and their parameters often have important scientific interpretations. In some applications, PDE parameters are not constant but can change depending on the values of covariates, a feature that we call varying coefficients. We propose a parameter cascading method to estimate varying coefficients in PDE models from noisy data. Our estimates of the varying coefficients are shown to be consistent and asymptotically normally distributed. The performance of our method is evaluated by a simulation study and by an empirical study estimating three varying coefficients in a PDE model arising from LIDAR data. © 2017, The International Biometric Society.

Tissue effects of Ho:YAG laser with varying fluences and pulse widths

NASA Astrophysics Data System (ADS)

Vari, Sandor G.; van der Veen, Maurits J.; Pergadia, Vani R.; Shi, Wei-Qiang; Duffy, J. T.; Weiss, Andrew B.; Fishbein, Michael C.; Grundfest, Warren S.

1994-02-01

We investigated the effect of varying fluence and pulse width on the ablation rate and consequent thermal damage of the Ho:YAG (2.130 micrometers ) laser. The rate of ablation on fresh bovine knee joint tissues, fibrous cartilage, hyaline cartilage, and bone in saline was determined after varying the fluence (160 - 640 J/cm2) and pulse width (150, 250, 450 microsecond(s) ec, FWHM) at a repetition rate of 2 Hz. A 400/440 micrometers fiber was used. The ablation rate increased linearly with the fluence. In fibrocartilage, different pulse durations generated significant changes in the ablation rates, but showed minor effects on hyaline cartilage and bone. The heat of ablation for all three tissue types decreased after lengthening the pulse.

Significant elevation of the levels of B-cell activating factor (BAFF) in patients with sarcoidosis.

PubMed

Ando, Masaru; Goto, Akihiko; Takeno, Yukiko; Yamasue, Mari; Komiya, Kosaku; Umeki, Kenji; Nureki, Shin-Ichi; Miyazaki, Eishi; Kadota, Jun-Ichi

2018-06-23

B-cell activating factor (BAFF) plays an important role in the survival and differentiation of B-cells and production of antibodies. Recent studies show that the serum BAFF levels are elevated in patients with sarcoidosis; however, they have not studied the relationship of the finding with the clinical features of the disease. The purpose of the present study is to analyze the BAFF and to elucidate the relationship between BAFF levels and the disease activity or severity of sarcoidosis. Eighty-eight patients with sarcoidosis and 21 healthy volunteers were enrolled in the present study. The BAFF levels were measured by an enzyme-linked immunosorbent assay. To assess the disease severity, we examined the number of affected organs, Schadding stages, respiratory function impairment (RFI), and the scoring system developed by Wasfi et al. The serum BAFF levels in sarcoidosis patients were significantly higher than those in healthy volunteers (median 1553.0 vs 984.6 pg/ml, p < 0.001). There were positive correlations between the serum BAFF level and disease activity markers. In addition, there were positive correlations between the BAFF levels and the disease severity score in both the serum (R = 0.367, p < 0.001) and bronchoalveolar lavage fluid (BALF) (R = 0.376, p < 0.001). This study demonstrated that the BAFF levels in both the serum and BALF were positively correlated with the disease activity markers and disease severity. BAFF may be useful as an indicator of both the disease activity and severity.

Rural Enterprises, Incorporated report of significant activities and accomplishments

NASA Technical Reports Server (NTRS)

1985-01-01

The ongoing activities of Rural Enterprises, Inc. are presented. The function of Rural Enterprises is to bring innovation from its rudimentary conceptual stages to useful and productive ends by means of cooperation with government, business, and educational institutions.

Time-Varying Vocal Folds Vibration Detection Using a 24 GHz Portable Auditory Radar.

PubMed

Hong, Hong; Zhao, Heng; Peng, Zhengyu; Li, Hui; Gu, Chen; Li, Changzhi; Zhu, Xiaohua

2016-07-28

Time-varying vocal folds vibration information is of crucial importance in speech processing, and the traditional devices to acquire speech signals are easily smeared by the high background noise and voice interference. In this paper, we present a non-acoustic way to capture the human vocal folds vibration using a 24-GHz portable auditory radar. Since the vocal folds vibration only reaches several millimeters, the high operating frequency and the 4 × 4 array antennas are applied to achieve the high sensitivity. The Variational Mode Decomposition (VMD) based algorithm is proposed to decompose the radar-detected auditory signal into a sequence of intrinsic modes firstly, and then, extract the time-varying vocal folds vibration frequency from the corresponding mode. Feasibility demonstration, evaluation, and comparison are conducted with tonal and non-tonal languages, and the low relative errors show a high consistency between the radar-detected auditory time-varying vocal folds vibration and acoustic fundamental frequency, except that the auditory radar significantly improves the frequency-resolving power.

The varied contribution of significant others to Complementary and Alternative Medicine (CAM) uptake by men with cancer: a qualitative analysis.

PubMed

Klafke, Nadja; Eliott, Jaklin A; Olver, Ian N; Wittert, Gary A

2014-06-01

To explore how men's Significant Others (SOs), including family members and close friends, contribute to the uptake and maintenance of specific CAM therapies. This study was the second, qualitative phase of a mixed-methods project investigating the use of CAM in an Australian male cancer population. Male participants were purposefully selected from a pool of 403 patients who answered a survey in the first quantitative phase (94% response rate and 86% consent rate for follow-up interview). Then semi-structured interviews among 26 men with a variety of cancers and 24 SOs were conducted. All 43 interviews were recorded, transcribed, and analysed thematically. Men used CAM/Natural products to cope with physical concerns, and this was actively supported by men's SOs who contributed to the uptake and maintenance of these CAMs. The shared CAM preparation and consumption functioned to strengthen the bond between men and their SOs, and also helped men's SOs to cope with uncertainty and regain control. In contrast, men practiced CAM/Mind-body medicine to receive emotional benefits, and only rarely shared this practice with their SOs, indicating a need for coping with emotions in a private way. Men's CAM use is a multifaceted process that can be better understood by considering CAM categories separately. CAM/Natural products help men to cope with physical concerns, while CAM/Mind-body medicine assist men to cope with their emotions in a private way. Oncology professionals can use this information to better promote and implement integrative cancer care services. Copyright © 2014 Elsevier Ltd. All rights reserved.

The Crowded Sea: Incorporating Multiple Marine Activities in Conservation Plans Can Significantly Alter Spatial Priorities

PubMed Central

Mazor, Tessa; Possingham, Hugh P.; Edelist, Dori; Brokovich, Eran; Kark, Salit

2014-01-01

Successful implementation of marine conservation plans is largely inhibited by inadequate consideration of the broader social and economic context within which conservation operates. Marine waters and their biodiversity are shared by a host of stakeholders, such as commercial fishers, recreational users and offshore developers. Hence, to improve implementation success of conservation plans, we must incorporate other marine activities while explicitly examining trade-offs that may be required. In this study, we test how the inclusion of multiple marine activities can shape conservation plans. We used the entire Mediterranean territorial waters of Israel as a case study to compare four planning scenarios with increasing levels of complexity, where additional zones, threats and activities were added (e.g., commercial fisheries, hydrocarbon exploration interests, aquaculture, and shipping lanes). We applied the marine zoning decision support tool Marxan to each planning scenario and tested a) the ability of each scenario to reach biodiversity targets, b) the change in opportunity cost and c) the alteration of spatial conservation priorities. We found that by including increasing numbers of marine activities and zones in the planning process, greater compromises are required to reach conservation objectives. Complex plans with more activities incurred greater opportunity cost and did not reach biodiversity targets as easily as simplified plans with less marine activities. We discovered that including hydrocarbon data in the planning process significantly alters spatial priorities. For the territorial waters of Israel we found that in order to protect at least 10% of the range of 166 marine biodiversity features there would be a loss of ∼15% of annual commercial fishery revenue and ∼5% of prospective hydrocarbon revenue. This case study follows an illustrated framework for adopting a transparent systematic process to balance biodiversity goals and economic

Sleep Duration Varies as a Function of Glutamate and GABA in Rat Pontine Reticular Formation

PubMed Central

Watson, Christopher J.; Lydic, Ralph; Baghdoyan, Helen A.

2011-01-01

The oral part of the pontine reticular formation (PnO) is a component of the ascending reticular activating system and plays a role in the regulation of sleep and wakefulness. The PnO receives glutamatergic and GABAergic projections from many brain regions that regulate behavioral state. Indirect, pharmacological evidence has suggested that glutamatergic and GABAergic signaling within the PnO alters traits that characterize wakefulness and sleep. No previous studies have simultaneously measured endogenous glutamate and GABA from rat PnO in relation to sleep and wakefulness. The present study utilized in vivo microdialysis coupled on-line to capillary electrophoresis with laser-induced fluorescence to test the hypothesis that concentrations of glutamate and GABA in the PnO vary across the sleep/wake cycle. Concentrations of glutamate and GABA were significantly higher during wakefulness than during NREM sleep and REM sleep. Regression analysis revealed that decreases in glutamate and GABA accounted for a significant portion of the variance in the duration of NREM sleep and REM sleep episodes. These data provide novel support for the hypothesis that endogenous glutamate and GABA in the PnO contribute to the regulation of sleep duration. PMID:21679185

Resting brain activity varies with dream recall frequency between subjects.

PubMed

Eichenlaub, Jean-Baptiste; Nicolas, Alain; Daltrozzo, Jérôme; Redouté, Jérôme; Costes, Nicolas; Ruby, Perrine

2014-06-01

Dreaming is still poorly understood. Notably, its cerebral underpinning remains unclear. Neuropsychological studies have shown that lesions in the temporoparietal junction (TPJ) and/or the white matter of the medial prefrontal cortex (MPFC) lead to the global cessation of dream reports, suggesting that these regions of the default mode network have key roles in the dreaming process (forebrain 'dream-on' hypothesis). To test this hypothesis, we measured regional cerebral blood flow (rCBF) using [(15)O]H2O positron emission tomography in healthy subjects with high and low dream recall frequencies (DRFs) during wakefulness (rest) and sleep (rapid eye movement (REM) sleep, N2, and N3). Compared with Low recallers (0.5 ± 0.3 dream recall per week in average), High recallers (5.2 ± 1.4) showed higher rCBF in the TPJ during REM sleep, N3, and wakefulness, and in the MPFC during REM sleep and wakefulness. We demonstrate that the resting states of High recallers and Low recallers differ during sleep and wakefulness. It coheres with previous ERP results and confirms that a high/low DRF is associated with a specific functional organization of the brain. These results support the forebrain 'dream-on' hypothesis and suggest that TPJ and MPFC are not only involved in dream recall during wakefulness but also have a role in dreaming during sleep (production and/or encoding). Increased activity in the TPJ and MPFC might promote the mental imagery and/or memory encoding of dreams. Notably, increased activity in TPJ might facilitate attention orienting toward external stimuli and promote intrasleep wakefulness, facilitating the encoding of the dreams in memory.

Resting Brain Activity Varies with Dream Recall Frequency Between Subjects

PubMed Central

Eichenlaub, Jean-Baptiste; Nicolas, Alain; Daltrozzo, Jérôme; Redouté, Jérôme; Costes, Nicolas; Ruby, Perrine

2014-01-01

Dreaming is still poorly understood. Notably, its cerebral underpinning remains unclear. Neuropsychological studies have shown that lesions in the temporoparietal junction (TPJ) and/or the white matter of the medial prefrontal cortex (MPFC) lead to the global cessation of dream reports, suggesting that these regions of the default mode network have key roles in the dreaming process (forebrain ‘dream-on' hypothesis). To test this hypothesis, we measured regional cerebral blood flow (rCBF) using [15O]H2O positron emission tomography in healthy subjects with high and low dream recall frequencies (DRFs) during wakefulness (rest) and sleep (rapid eye movement (REM) sleep, N2, and N3). Compared with Low recallers (0.5±0.3 dream recall per week in average), High recallers (5.2±1.4) showed higher rCBF in the TPJ during REM sleep, N3, and wakefulness, and in the MPFC during REM sleep and wakefulness. We demonstrate that the resting states of High recallers and Low recallers differ during sleep and wakefulness. It coheres with previous ERP results and confirms that a high/low DRF is associated with a specific functional organization of the brain. These results support the forebrain ‘dream-on' hypothesis and suggest that TPJ and MPFC are not only involved in dream recall during wakefulness but also have a role in dreaming during sleep (production and/or encoding). Increased activity in the TPJ and MPFC might promote the mental imagery and/or memory encoding of dreams. Notably, increased activity in TPJ might facilitate attention orienting toward external stimuli and promote intrasleep wakefulness, facilitating the encoding of the dreams in memory. PMID:24549103

Physical activity school intervention: context matters.

PubMed

Guldager, J D; Andersen, P T; von Seelen, J; Leppin, A

2018-06-01

School-based interventions for increasing physical activity among children are widespread, however there is still a lack of knowledge about how school context factors are linked to implementation quality and effectiveness of programmes. The aim of this paper is to examine teacher-perceived effectiveness of a Danish national classroom-based health programme 'Active Around Denmark' and in particular, to investigate whether perceptions vary as a function of school social context factors. After completion of the programme all teachers (N = 5.892) received an electronic questionnaire. 2.097 completed the questionnaire (response rate 36%) and 1.781 datasets could be used for analysis. The teachers were asked about their perceptions of changes in children's attitudes towards and levels of physical activity after the competition. Our results indicated that certain contextual factors, such as schools' prioritization of health promotion, teachers' support by their school principal in implementation as well as teacher's satisfaction with the school' physical environment made a significant difference in teacher-perceived effectiveness. To conclude, teacher-perceived effectiveness of the health programme does vary as a function of school social context factors.

Surrogate markers for time-varying treatments and outcomes

PubMed Central

Hsu, Jesse Y; Kennedy, Edward H; Roy, Jason A; Stephens-Shields, Alisa J; Small, Dylan S; Joffe, Marshall M

2015-01-01

Background A surrogate marker is a variable commonly used in clinical trials to guide treatment decisions when the outcome of ultimate interest is not available. A good surrogate marker is one where the treatment effect on the surrogate is a strong predictor of the effect of treatment on the outcome. We review the situation when there is one treatment delivered at baseline, one surrogate measured at one later time point and one ultimate outcome of interest, and discuss new issues arising when variables are time-varying. Methods Most of the literature on surrogate markers has only considered simple settings with one treatment, one surrogate, and one outcome of interest at a fixed time point. However, more complicated time-varying settings are common in practice. In this paper, we describe the unique challenges in two settings, time-varying treatments and time-varying surrogates, while relating the ideas back to the causal-effects and causal-association paradigms. Conclusions In addition to discussing and extending popular notions of surrogacy to time-varying settings, we give examples illustrating that one can be misled by not taking into account time-varying information about the surrogate or treatment. We hope this paper has provided some motivation for future work on estimation and inference in such settings. PMID:25948621

Allopatric integrations selectively change host transcriptomes, leading to varied expression efficiencies of exotic genes in Myxococcus xanthus.

PubMed

Zhu, Li-Ping; Yue, Xin-Jing; Han, Kui; Li, Zhi-Feng; Zheng, Lian-Shuai; Yi, Xiu-Nan; Wang, Hai-Long; Zhang, You-Ming; Li, Yue-Zhong

2015-07-22

Exotic genes, especially clustered multiple-genes for a complex pathway, are normally integrated into chromosome for heterologous expression. The influences of insertion sites on heterologous expression and allotropic expressions of exotic genes on host remain mostly unclear. We compared the integration and expression efficiencies of single and multiple exotic genes that were inserted into Myxococcus xanthus genome by transposition and attB-site-directed recombination. While the site-directed integration had a rather stable chloramphenicol acetyl transferase (CAT) activity, the transposition produced varied CAT enzyme activities. We attempted to integrate the 56-kb gene cluster for the biosynthesis of antitumor polyketides epothilones into M. xanthus genome by site-direction but failed, which was determined to be due to the insertion size limitation at the attB site. The transposition technique produced many recombinants with varied production capabilities of epothilones, which, however, were not paralleled to the transcriptional characteristics of the local sites where the genes were integrated. Comparative transcriptomics analysis demonstrated that the allopatric integrations caused selective changes of host transcriptomes, leading to varied expressions of epothilone genes in different mutants. With the increase of insertion fragment size, transposition is a more practicable integration method for the expression of exotic genes. Allopatric integrations selectively change host transcriptomes, which lead to varied expression efficiencies of exotic genes.

Age-varying associations between substance use behaviors and depressive symptoms during adolescence and young adulthood.

PubMed

Schuler, Megan S; Vasilenko, Sara A; Lanza, Stephanie T

2015-12-01

Substance use and depression often co-occur, complicating treatment of both substance use and depression. Despite research documenting age-related trends in both substance use and depression, little research has examined how the associations between substance use behaviors and depression changes across the lifespan. This study examines how the associations between substance use behaviors (daily smoking, regular heavy episodic drinking (HED), and marijuana use) and depressive symptoms vary from adolescence into young adulthood (ages 12-31), and how these associations differ by gender. Using data from the National Longitudinal Study of Adolescent to Adult Health (Add Health), we implemented time-varying effect models (TVEM), an analytic approach that estimates how the associations between predictors (e.g., substance use measures) and an outcome (e.g., depressive symptoms) vary across age. Marijuana use and daily smoking were significantly associated with depressive symptoms at most ages from 12 to 31. Regular HED was significantly associated with depressive symptoms during adolescence only. In bivariate analyses, the association with depressive symptoms for each substance use behavior was significantly stronger for females at certain ages; when adjusting for concurrent substance use in a multivariate analysis, no gender differences were observed. While the associations between depressive symptoms and both marijuana and daily smoking were relatively stable across ages 12-31, regular HED was only significantly associated with depressive symptoms during adolescence. Understanding age and gender trends in these associations can help tailor prevention efforts and joint treatment methods in order to maximize public health benefit. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

A VARI-Based Relative Greenness from MODIS Data for Computing the Fire Potential Index

NASA Technical Reports Server (NTRS)

Schneider, P.; Roberts, D. A.; Kyriakidis, P. C.

2008-01-01

The Fire Potential Index (FPI) relies on relative greenness (RG) estimates from remote sensing data. The Normalized Difference Vegetation index (NDVI), derived from NOAA Advanced Very High Resolution Radiometer (AVHRR) imagery is currently used to calculate RG operationally. Here we evaluated an alternate measure of RG using the Visible Atmospheric Resistant Index (VARI) derived from Moderate Resolution Imaging Spectrometer (MODIS) data. VARI was chosen because it has previously been shown to have the strongest relationship with Live Fuel Moisture (LFM) out of a wide selection of MODIS-derived indices in southern California shrublands. To compare MODIS-based NDVI-FPI and VARI-FPI, RG was calculated from a 6-year time series of MODIS composites and validated against in-situ observations of LFM as a surrogate for vegetation greenness. RG from both indices was then compared in terms of its performance for computing the FPI using historical wildfire data. Computed RG values were regressed against ground-sampled LFM at 14 sites within Los Angeles County. The results indicate the VARI-based RG consistently shows a stronger relationship with observed LFM than NDVI-based RG. With an average R2 of 0.727 compared to a value of only 0.622 for NDVI-RG, VARI-RG showed stronger relationships at 13 out of 14 sites. Based on these results, daily FPI maps were computed for the years 2001 through 2005 using both NDVI-RG and VARI-RG. These were then validated against 12,490 fire detections from the MODIS active fire product using logistic regression. Deviance of the logistic regression model was 408.8 for NDVI-FPI and 176.2 for VARI-FPI. The c-index was found to be 0.69 and 0.78, respectively. The results show that VARI-FP outperforms NDVI-FPI in distinguishing between fire and no-fire events for historical wildfire data in southern California for the given time period.

Retinal specialization through spatially varying cell densities and opsin coexpression in cichlid fish.

PubMed

Dalton, Brian E; de Busserolles, Fanny; Marshall, N Justin; Carleton, Karen L

2017-01-15

The distinct behaviours of animals and the varied habitats in which animals live place different requirements on their visual systems. A trade-off exists between resolution and sensitivity, with these properties varying across the retina. Spectral sensitivity, which affects both achromatic and chromatic (colour) vision, also varies across the retina, though the function of this inhomogeneity is less clear. We previously demonstrated spatially varying spectral sensitivity of double cones in the cichlid fish Metriaclima zebra owing to coexpression of different opsins. Here, we map the distributions of ganglion cells and cone cells and quantify opsin coexpression in single cones to show these also vary across the retina. We identify an area centralis with peak acuity and infrequent coexpression, which may be suited for tasks such as foraging and detecting male signals. The peripheral retina has reduced ganglion cell densities and increased opsin coexpression. Modeling of cichlid visual tasks indicates that coexpression might hinder colour discrimination of foraging targets and some fish colours. But, coexpression might improve contrast detection of dark objects against bright backgrounds, which might be useful for detecting predators or zooplankton. This suggests a trade-off between acuity and colour discrimination in the central retina versus lower resolution but more sensitive contrast detection in the peripheral retina. Significant variation in the pattern of coexpression among individuals, however, raises interesting questions about the selective forces at work. © 2017. Published by The Company of Biologists Ltd.

Thermal design and simulation of an attitude-varied space camera

NASA Astrophysics Data System (ADS)

Wang, Chenjie; Yang, Wengang; Feng, Liangjie; Li, XuYang; Wang, Yinghao; Fan, Xuewu; Wen, Desheng

2015-10-01

An attitude-varied space camera changes attitude continually when it is working, its attitude changes with large angle in short time leads to the significant change of heat flux; Moreover, the complicated inner heat sources, other payloads and the satellite platform will also bring thermal coupling effects to the space camera. According to a space camera which is located on a two dimensional rotating platform, detailed thermal design is accomplished by means of thermal isolation, thermal transmission and temperature compensation, etc. Then the ultimate simulation cases of both high temperature and low temperature are chosen considering the obscuration of the satellite platform and other payloads, and also the heat flux analysis of light entrance and radiator surface of the camera. NEVEDA and SindaG are used to establish the simulation model of the camera and the analysis is carried out. The results indicate that, under both passive and active thermal control, the temperature of optical components is 20+/-1°C,both their radial and axial temperature gradient are less than 0.3°C, while the temperature of the main structural components is 20+/-2°C, and the temperature fluctuation of the focal plane assemblies is 3.0-9.5°C The simulation shows that the thermal control system can meet the need of the mission, and the thermal design is efficient and reasonable.

Protein dynamics in organic media at varying water activity studied by molecular dynamics simulation.

PubMed

Wedberg, Rasmus; Abildskov, Jens; Peters, Günther H

2012-03-01

In nonaqueous enzymology, control of enzyme hydration is commonly approached by fixing the thermodynamic water activity of the medium. In this work, we present a strategy for evaluating the water activity in molecular dynamics simulations of proteins in water/organic solvent mixtures. The method relies on determining the water content of the bulk phase and uses a combination of Kirkwood-Buff theory and free energy calculations to determine corresponding activity coefficients. We apply the method in a molecular dynamics study of Candida antarctica lipase B in pure water and the organic solvents methanol, tert-butyl alcohol, methyl tert-butyl ether, and hexane, each mixture at five different water activities. It is shown that similar water activity yields similar enzyme hydration in the different solvents. However, both solvent and water activity are shown to have profound effects on enzyme structure and flexibility.

Bioassay of plant growth from soils varying in active C and N fractions

USDA-ARS?s Scientific Manuscript database

Biologically active soil C and N fractions are important attributes of healthy soil. As a bioassay, we hypothesized that active soil C and N fractions would relate with plant dry matter production from unamended soil. Four replicate soil samples from 22 tall fescue fields in North Carolina and Virgi...

Cortical Activation in Response to Pure Taste Stimuli During the Physiological States of Hunger and Satiety

PubMed Central

Haase, Lori; Cerf-Ducastel, Barbara; Murphy, Claire

2009-01-01

This event-related functional magnetic resonance imaging (er-fMRI) study investigated BOLD signal change in response to a series of pure gustatory stimuli that varied in stimulus quality when subjects were hungry and sated with a nutritional preload. Group analyses showed significant differences in activation in the hunger minus satiety condition in response to sucrose, caffeine, saccharin, and citric acid within the thalamus, hippocampus, and parahippocampus. When examining the hunger and satiety conditions, activation varied as a function of stimulus, with the majority of the stimuli exhibiting significantly greater activation in the hunger state within the insula, thalamus, and substantia nigra, in contrast to decreased activation in the satiated state within the parahippocampus, hippocampus, amygdala, and anterior cingulate. Region of interest (ROI) analysis revealed two significant interactions, ROI by physiology and ROI by physiology by stimulus. In the satiety condition, the primary (inferior and superior insulae) and secondary (OFC 11 and OFC 47) taste regions exhibited significantly greater brain activation in response to all stimuli than regions involved in processing eating behavior (hypothalamus), affect (amygdala), and memory (hippocampus, parahippocampus and entorhinal cortex). These same regions demonstrated significantly greater activation within the hunger condition than the satiety condition, with the exception of the superior insula. Furthermore, the patterns of activation differed as a function taste stimulus, with greater activation in response to sucrose than to the other stimuli. These differential patterns of activation suggest that the physiological states of hunger and satiety produce divergent activation in multiple brain areas in response to different pure gustatory stimuli. PMID:19007893

Cortical activation in response to pure taste stimuli during the physiological states of hunger and satiety.

PubMed

Haase, Lori; Cerf-Ducastel, Barbara; Murphy, Claire

2009-02-01

This event-related functional magnetic resonance imaging (er-fMRI) study investigated BOLD signal change in response to a series of pure gustatory stimuli that varied in stimulus quality when subjects were hungry and sated with a nutritional pre-load. Group analyses showed significant differences in activation in the hunger minus satiety condition in response to sucrose, caffeine, saccharin, and citric acid within the thalamus, hippocampus, and parahippocampus. When examining the hunger and satiety conditions, activation varied as a function of stimulus, with the majority of the stimuli exhibiting significantly greater activation in the hunger state within the insula, thalamus, and substantia nigra, in contrast to decreased activation in the satiated state within the parahippocampus, hippocampus, amygdala, and anterior cingulate. Region of interest (ROI) analysis revealed two significant interactions, ROI by physiology and ROI by physiology by stimulus. In the satiety condition, the primary (inferior and superior insulae) and secondary (OFC 11 and OFC 47) taste regions exhibited significantly greater brain activation in response to all stimuli than regions involved in processing eating behavior (hypothalamus), affect (amygdala), and memory (hippocampus, parahippocampus and entorhinal cortex). These same regions demonstrated significantly greater activation within the hunger condition than the satiety condition, with the exception of the superior insula. Furthermore, the patterns of activation differed as a function taste stimulus, with greater activation in response to sucrose than to the other stimuli. These differential patterns of activation suggest that the physiological states of hunger and satiety produce divergent activation in multiple brain areas in response to different pure gustatory stimuli.

Generalized semiparametric varying-coefficient models for longitudinal data

NASA Astrophysics Data System (ADS)

Qi, Li

In this dissertation, we investigate the generalized semiparametric varying-coefficient models for longitudinal data that can flexibly model three types of covariate effects: time-constant effects, time-varying effects, and covariate-varying effects, i.e., the covariate effects that depend on other possibly time-dependent exposure variables. First, we consider the model that assumes the time-varying effects are unspecified functions of time while the covariate-varying effects are parametric functions of an exposure variable specified up to a finite number of unknown parameters. The estimation procedures are developed using multivariate local linear smoothing and generalized weighted least squares estimation techniques. The asymptotic properties of the proposed estimators are established. The simulation studies show that the proposed methods have satisfactory finite sample performance. ACTG 244 clinical trial of HIV infected patients are applied to examine the effects of antiretroviral treatment switching before and after HIV developing the 215-mutation. Our analysis shows benefit of treatment switching before developing the 215-mutation. The proposed methods are also applied to the STEP study with MITT cases showing that they have broad applications in medical research.

Prospective Relations between Organized Activity Participation and Psychopathology during Adolescence

ERIC Educational Resources Information Center

Bohnert, Amy M.; Garber, Judy

2007-01-01

This longitudinal study examined psychopathology as a predictor and outcome of organized activity involvement during high school among 198 adolescents who varied in risk for psychopathology as a function of their mother's depression history. Higher levels of internalizing and externalizing symptoms in eighth grade significantly predicted lower…

Synchronized state of coupled dynamics on time-varying networks.

PubMed

Amritkar, R E; Hu, Chin-Kun

2006-03-01

We consider synchronization properties of coupled dynamics on time-varying networks and the corresponding time-average network. We find that if the different Laplacians corresponding to the time-varying networks commute with each other then the stability of the synchronized state for both the time-varying and the time-average topologies are approximately the same. On the other hand for noncommuting Laplacians the stability of the synchronized state for the time-varying topology is in general better than the time-average topology.

Task-induced Changes in Idiopathic Infantile Nystagmus Vary with Gaze.

PubMed

Salehi Fadardi, Marzieh; Bathke, Arne C; Harrar, Solomon W; Abel, Larry Allen

2017-05-01

Investigations of infantile nystagmus syndrome (INS) at center or at the null position have reported that INS worsens when visual demand is combined with internal states, e.g. stress. Visual function and INS parameters such as foveation time, frequency, amplitude, and intensity can also be influenced by gaze position. We hypothesized that increases from baseline in visual demand and mental load would affect INS parameters at the null position differently than at other gaze positions. Eleven participants with idiopathic INS were asked to determine the direction of Tumbling-E targets, whose visual demand was varied through changes in size and contrast, using a staircase procedure. Targets appeared between ±25° in 5° steps. The task was repeated with both mental arithmetic and time restriction to impose higher mental load, confirmed through subjective ratings and concurrent physiological measurements. Within-subject comparisons were limited to the null and 15° away from it. No significant main effects of task on any INS parameters were found. At both locations, high mental load worsened task performance metrics, i.e. lowest contrast (P = .001) and smallest optotype size reached (P = .012). There was a significant interaction between mental load and gaze position for foveation time (P = .02) and for the smallest optotype reached (P = .028). The increase in threshold optotype size from the low to high mental load was greater at the null than away from it. During high visual demand, foveation time significantly decreased from baseline at the null as compared to away from it (mean difference ± SE: 14.19 ± 0.7 msec; P = .010). Under high visual demand, the effects of increased mental load on foveation time and visual task performance differed at the null as compared to 15° away from it. Assessment of these effects could be valuable when evaluating INS clinically and when considering its impact on patients' daily activities.

Alteration and modulation of protein activity by varying post-translational modification

DOEpatents

Thompson, David N; Reed, David W; Thompson, Vicki S; Lacey, Jeffrey A; Apel, William A

2015-03-03

Embodiments of the invention include methods of altering the enzymatic activity or solubility of an extremophilic enzyme or post-translationally modifying a protein of interest via using isolated or partially purified glycosyltransferases and/or post-translational modification proteins, extracts of cells comprising glycosyltransferases and/or post-translational modification proteins, and/or in cells comprising one or more glycosyltransferases and/or post-translational modification proteins.

Alteration and modulation of protein activity by varying post-translational modification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thompson, David N.; Reed, David W.; Thompson, Vicki S.

Embodiments of the invention include methods of altering the enzymatic activity or solubility of an extremophilic enzyme or post-translationally modifying a protein of interest via using isolated or partially purified glycosyltransferases and/or post-translational modification proteins, extracts of cells comprising glycosyltransferases and/or post-translational modification proteins, and/or in cells comprising one or more glycosyltransferases and/or post-translational modification proteins.

Wave scattering by an axisymmetric ice floe of varying thickness

NASA Astrophysics Data System (ADS)

Bennetts, Luke G.; Biggs, Nicholas R. T.; Porter, David

2009-04-01

The problem of water wave scattering by a circular ice floe, floating in fluid of finite depth, is formulated and solved numerically. Unlike previous investigations of such situations, here we allow the thickness of the floe (and the fluid depth) to vary axisymmetrically and also incorporate a realistic non-zero draught. A numerical approximation to the solution of this problem is obtained to an arbitrary degree of accuracy by combining a Rayleigh-Ritz approximation of the vertical motion with an appropriate variational principle. This numerical solution procedure builds upon the work of Bennets et al. (2007, J. Fluid Mech., 579, 413-443). As part of the numerical formulation, we utilize a Fourier cosine expansion of the azimuthal motion, resulting in a system of ordinary differential equations to solve in the radial coordinate for each azimuthal mode. The displayed results concentrate on the response of the floe rather than the scattered wave field and show that the effects of introducing the new features of varying floe thickness and a realistic draught are significant.

Habitat degradation affects the summer activity of polar bears.

PubMed

Ware, Jasmine V; Rode, Karyn D; Bromaghin, Jeffrey F; Douglas, David C; Wilson, Ryan R; Regehr, Eric V; Amstrup, Steven C; Durner, George M; Pagano, Anthony M; Olson, Jay; Robbins, Charles T; Jansen, Heiko T

2017-05-01

Understanding behavioral responses of species to environmental change is critical to forecasting population-level effects. Although climate change is significantly impacting species' distributions, few studies have examined associated changes in behavior. Polar bear (Ursus maritimus) subpopulations have varied in their near-term responses to sea ice decline. We examined behavioral responses of two adjacent subpopulations to changes in habitat availability during the annual sea ice minimum using activity data. Location and activity sensor data collected from 1989 to 2014 for 202 adult female polar bears in the Southern Beaufort Sea (SB) and Chukchi Sea (CS) subpopulations were used to compare activity in three habitat types varying in prey availability: (1) land; (2) ice over shallow, biologically productive waters; and (3) ice over deeper, less productive waters. Bears varied activity across and within habitats with the highest activity at 50-75% sea ice concentration over shallow waters. On land, SB bears exhibited variable but relatively high activity associated with the use of subsistence-harvested bowhead whale carcasses, whereas CS bears exhibited low activity consistent with minimal feeding. Both subpopulations had fewer observations in their preferred shallow-water sea ice habitats in recent years, corresponding with declines in availability of this substrate. The substantially higher use of marginal habitats by SB bears is an additional mechanism potentially explaining why this subpopulation has experienced negative effects of sea ice loss compared to the still-productive CS subpopulation. Variability in activity among, and within, habitats suggests that bears alter their behavior in response to habitat conditions, presumably in an attempt to balance prey availability with energy costs.

Hydraulic properties of fronds from palms of varying height and habitat.

PubMed

Renninger, Heidi J; Phillips, Nathan

2011-12-01

Because palms grow in highly varying climates and reach considerable heights, they present a unique opportunity to evaluate how environment and plant size impact hydraulic function. We studied hydraulic properties of petioles from palms of varying height from three species: Iriartea deltoidea, a tropical rainforest species; Mauritia flexuosa, a tropical rainforest, swamp species; and Washingtonia robusta, a subtropical species. We measured leaf areas, petiole cross-sectional areas, specific conductivity (K(S)), petiole anatomical properties, vulnerability to embolism and leaf water potentials and calculated petiole Huber values and leaf-specific conductivities (K(L)). Leaf and petiole cross-sectional areas varied widely with height. However, hydraulic properties including Huber values, K(S) and K(L), remained constant. The two palmate species, M. flexuosa and W. robusta, had larger Huber values than I. deltoidea, a pinnately-compound species which exhibited the highest K(S). Metaxylem vessel diameters and vascular bundle densities varied with height in opposing patterns to maintain petiole conductivities. I. deltoidea and W. robusta petioles had similar P(50) values (the point at which 50% of hydraulic conductivity is lost) averaged over all crown heights, but W. robusta exhibited more negative P(50) values in taller palms. Comparison of P (50) values with transpiring midday leaf water potentials, as well as a double-dye staining experiment in a 1-m-tall palm, suggested that a fairly significant amount of embolisms were occurring and refilled on a diurnal basis. Therefore, across palms differing widely in height and growing environments, we found convergence in water transport per unit leaf area (K(L)) with individuals exhibiting differing strategies for achieving this.

Failure Modes in Capacitors When Tested Under a Time-Varying Stress

NASA Technical Reports Server (NTRS)

Liu, David (Donhang)

2011-01-01

Steady step surge testing (SSST) is widely applied to screen out potential power-on failures in solid tantalum capacitors. The test simulates the power supply's on and off characteristics. Power-on failure has been the prevalent failure mechanism for solid tantalum capacitors for decoupling applications. On the other hand, the SSST can also be reviewed as an electrically destructive test under a time-varying stress. It consists of rapidly charging the capacitor with incremental voltage increases, through a low resistance in series, until the capacitor under test is electrically shorted. Highly accelerated life testing (HALT) is usually a time-efficient method for determining the failure mechanism in capacitors; however, a destructive test under a time-varying stress like SSST is even more effective. It normally takes days to complete a HALT test, but it only takes minutes for a time-varying stress test to produce failures. The advantage of incorporating specific time-varying stress into a statistical model is significant in providing an alternative life test method for quickly revealing the failure modes in capacitors. In this paper, a time-varying stress has been incorporated into the Weibull model to characterize the failure modes. The SSST circuit and transient conditions to correctly test the capacitors is discussed. Finally, the SSST was applied for testing polymer aluminum capacitors (PA capacitors), Ta capacitors, and multi-layer ceramic capacitors with both precious metal electrode (PME) and base-metal-electrodes (BME). It appears that testing results are directly associated to the dielectric layer breakdown in PA and Ta capacitors and are independent on the capacitor values, the way the capacitors being built, and the manufactures. The testing results also reveal that ceramic capacitors exhibit breakdown voltages more than 20 times the rated voltage, and the breakdown voltages are inverse proportional to the dielectric layer thickness. The possibility of

Activation in brain energy regulation and reward centers by food cues varies with choice of visual stimulus.

PubMed

Schur, E A; Kleinhans, N M; Goldberg, J; Buchwald, D; Schwartz, M W; Maravilla, K

2009-06-01

To develop a non-invasive method of studying brain mechanisms involved in energy homeostasis and appetite regulation in humans by using visual food cues that are relevant to individuals attempting weight loss. Functional magnetic resonance imaging (fMRI) was used to compare brain activation in regions of interest between groups of food photographs. Ten healthy, non-obese women who were not dieting for weight loss. Independent raters viewed food photographs and evaluated whether the foods depicted should be eaten by individuals attempting a calorically-restricted diet. Based on their responses, we categorized photographs into 'non-fattening' and 'fattening' food groups, the latter characterized by high-caloric content and usually also high-fat or high-sugar content. Blood oxygen level-dependent (BOLD) response was measured by fMRI while participants viewed photographs of 'fattening' food, 'non-fattening' food, and non-food objects. Viewing photographs of fattening food compared with non-food objects resulted in significantly greater activation in the brainstem; hypothalamus; left amygdala; left dorsolateral prefrontal cortex; left orbitofrontal cortex; right insular cortex; bilateral striatum, including the nucleus accumbens, caudate nucleus, and putamen; bilateral thalamus; and occipital lobe. By comparison, only the occipital region had greater activation by non-fattening food than by object photographs. Combining responses to all food types resulted in attenuation of activation in the brainstem, hypothalamus, and striatum. These findings suggest that, in non-obese women, neural circuits engaged in energy homeostasis and reward processing are selectively attuned to representations of high-calorie foods that are perceived as fattening. Studies to investigate hormonal action or manipulation of energy balance may benefit from fMRI protocols that contrast energy-rich food stimuli with non-food or low-calorie food stimuli.

Factors in youth physical activity participation: from psychological aspects to environmental correlates.

PubMed

Salmon, Jo

2010-01-01

Understanding influences on children's physical activity and how these vary by activity and subgroup, such as age and sex of the child, is important for informing the development of effective and targeted interventions. Two cohort studies were conducted across socioeconomic areas of Melbourne, Australia, between 2001 and 2008 among a combined sample of more than 2,700 children aged 5-6 years and 10-12 years at baseline. Data were collected via surveys, and children wore the Actigraph accelerometer for 8 days. Five individual, 10 social, and 17 physical environmental factors were significantly associated with children's physical activity. Patterns of association varied according to the age and sex of the child and also according to the type of activity. These studies provide some insights into the various levels of influence on children's physical activity. More longitudinal and intervention research is needed to better understand the mechanisms of change in children's physical activity behaviour.

Song trait similarity in great tits varies with social structure.

PubMed

Snijders, Lysanne; van der Eijk, Jerine; van Rooij, Erica P; de Goede, Piet; van Oers, Kees; Naguib, Marc

2015-01-01

For many animals, long-range signalling is essential to maintain contact with conspecifics. In territorial species, individuals often have to balance signalling towards unfamiliar potential competitors (to solely broadcast territory ownership) with signalling towards familiar immediate neighbours (to also maintain so-called "dear enemy" relations). Hence, to understand how signals evolve due to these multilevel relationships, it is important to understand how general signal traits vary in relation to the overall social environment. For many territorial songbirds dawn is a key signalling period, with several neighbouring individuals singing simultaneously without immediate conflict. In this study we tested whether sharing a territory boundary, rather than spatial proximity, is related to similarity in dawn song traits between territorial great tits (Parus major) in a wild personality-typed population. We collected a large dataset of automatized dawn song recordings from 72 unique male great tits, during the fertile period of their mate, and compared specific song traits between neighbours and non-neighbours. We show here that both song rate and start time of dawn song were repeatable song traits. Moreover, neighbours were significantly more dissimilar in song rate compared to non-neighbours, while there was no effect of proximity on song rate similarity. Additionally, similarity in start time of dawn song was unrelated to sharing a territory boundary, but birds were significantly more similar in start time of dawn song when they were breeding in close proximity of each other. We suggest that the dissimilarity in dawn song rate between neighbours is either the result of neighbouring great tits actively avoiding similar song rates to possibly prevent interference, or a passive consequence of territory settlement preferences relative to the types of neighbours. Neighbourhood structuring is therefore likely to be a relevant selection pressure shaping variation in

Mediation analysis with time varying exposures and mediators.

PubMed

VanderWeele, Tyler J; Tchetgen Tchetgen, Eric J

2017-06-01

In this paper we consider causal mediation analysis when exposures and mediators vary over time. We give non-parametric identification results, discuss parametric implementation, and also provide a weighting approach to direct and indirect effects based on combining the results of two marginal structural models. We also discuss how our results give rise to a causal interpretation of the effect estimates produced from longitudinal structural equation models. When there are time-varying confounders affected by prior exposure and mediator, natural direct and indirect effects are not identified. However, we define a randomized interventional analogue of natural direct and indirect effects that are identified in this setting. The formula that identifies these effects we refer to as the "mediational g-formula." When there is no mediation, the mediational g-formula reduces to Robins' regular g-formula for longitudinal data. When there are no time-varying confounders affected by prior exposure and mediator values, then the mediational g-formula reduces to a longitudinal version of Pearl's mediation formula. However, the mediational g-formula itself can accommodate both mediation and time-varying confounders and constitutes a general approach to mediation analysis with time-varying exposures and mediators.

Behavioural Lateralization in Budgerigars Varies with the Task and the Individual

PubMed Central

Schiffner, Ingo; Srinivasan, Mandyam V.

2013-01-01

Handedness/footedness and side biases are a well-known phenomenon in many animals, including humans. However, these so-called biases have mostly been studied at the population level - individual biases have received less attention, especially with regard to consistency over different tasks. Here we investigate behavioral lateralization in 12 male Budgerigars, Melopsittacus undulatus, a social parrot inhabiting the Australian bushlands. We performed 5 types of experiments to investigate lateralization, in tasks that involved climbing onto a perch, or landing on perches arranged in various configurations. The birds displayed highly significant, individually varying biases. The bias displayed by any particular individual varied with the task, in strength as well as polarity. Analysis of the data revealed that the preferred foot used for climbing did not coincide with the foot that was used while landing. Thus, landing choices are probably not determined by foot bias. Furthermore, these individual preferences were overridden completely when a bird had to perform a task simultaneously with another bird. PMID:24324820

Time-Varying Vocal Folds Vibration Detection Using a 24 GHz Portable Auditory Radar

PubMed Central

Hong, Hong; Zhao, Heng; Peng, Zhengyu; Li, Hui; Gu, Chen; Li, Changzhi; Zhu, Xiaohua

2016-01-01

Time-varying vocal folds vibration information is of crucial importance in speech processing, and the traditional devices to acquire speech signals are easily smeared by the high background noise and voice interference. In this paper, we present a non-acoustic way to capture the human vocal folds vibration using a 24-GHz portable auditory radar. Since the vocal folds vibration only reaches several millimeters, the high operating frequency and the 4 × 4 array antennas are applied to achieve the high sensitivity. The Variational Mode Decomposition (VMD) based algorithm is proposed to decompose the radar-detected auditory signal into a sequence of intrinsic modes firstly, and then, extract the time-varying vocal folds vibration frequency from the corresponding mode. Feasibility demonstration, evaluation, and comparison are conducted with tonal and non-tonal languages, and the low relative errors show a high consistency between the radar-detected auditory time-varying vocal folds vibration and acoustic fundamental frequency, except that the auditory radar significantly improves the frequency-resolving power. PMID:27483261

Changes of the time-varying percentiles of daily extreme temperature in China

NASA Astrophysics Data System (ADS)

Li, Bin; Chen, Fang; Xu, Feng; Wang, Xinrui

2017-11-01

Identifying the air temperature frequency distributions and evaluating the trends in time-varying percentiles are very important for climate change studies. In order to get a better understanding of the recent temporal and spatial pattern of the temperature changes in China, we have calculated the trends in temporal-varying percentiles of the daily extreme air temperature firstly. Then we divide all the stations to get the spatial patterns for the percentile trends using the average linkage cluster analysis method. To make a comparison, the shifts of trends percentile frequency distribution from 1961-1985 to 1986-2010 are also examined. Important results in three aspects have been achieved: (1) In terms of the trends in temporal-varying percentiles of the daily extreme air temperature, the most intense warming for daily maximum air temperature (Tmax) was detected in the upper percentiles with a significant increasing tendency magnitude (>2.5 °C/50year), and the greatest warming for daily minimum air temperature (Tmin) occurred with very strong trends exceeding 4 °C/50year. (2) The relative coherent spatial patterns for the percentile trends were found, and stations for the whole country had been divided into three clusters. The three primary clusters were distributed regularly to some extent from north to south, indicating the possible large influence of the latitude. (3) The most significant shifts of trends percentile frequency distribution from 1961-1985 to 1986-2010 was found in Tmax. More than half part of the frequency distribution show negative trends less than -0.5 °C/50year in 1961-1985, while showing trends less than 2.5 °C/50year in 1986-2010.

Nonlinear recurrent neural networks for finite-time solution of general time-varying linear matrix equations.

PubMed

Xiao, Lin; Liao, Bolin; Li, Shuai; Chen, Ke

2018-02-01

In order to solve general time-varying linear matrix equations (LMEs) more efficiently, this paper proposes two nonlinear recurrent neural networks based on two nonlinear activation functions. According to Lyapunov theory, such two nonlinear recurrent neural networks are proved to be convergent within finite-time. Besides, by solving differential equation, the upper bounds of the finite convergence time are determined analytically. Compared with existing recurrent neural networks, the proposed two nonlinear recurrent neural networks have a better convergence property (i.e., the upper bound is lower), and thus the accurate solutions of general time-varying LMEs can be obtained with less time. At last, various different situations have been considered by setting different coefficient matrices of general time-varying LMEs and a great variety of computer simulations (including the application to robot manipulators) have been conducted to validate the better finite-time convergence of the proposed two nonlinear recurrent neural networks. Copyright © 2017 Elsevier Ltd. All rights reserved.

Local inertial oscillations in the surface ocean generated by time-varying winds

NASA Astrophysics Data System (ADS)

Chen, Shengli; Polton, Jeff A.; Hu, Jianyu; Xing, Jiuxing

2015-12-01

A new relationship is presented to give a review study on the evolution of inertial oscillations in the surface ocean locally generated by time-varying wind stress. The inertial oscillation is expressed as the superposition of a previous oscillation and a newly generated oscillation, which depends upon the time-varying wind stress. This relationship is employed to investigate some idealized wind change events. For a wind series varying temporally with different rates, the induced inertial oscillation is dominated by the wind with the greatest variation. The resonant wind, which rotates anti-cyclonically at the local inertial frequency with time, produces maximal amplitude of inertial oscillations, which grows monotonically. For the wind rotating at non-inertial frequencies, the responses vary periodically, with wind injecting inertial energy when it is in phase with the currents, but removing inertial energy when it is out of phase. The wind rotating anti-cyclonically with time is much more favorable to generate inertial oscillations than the cyclonic rotating wind. The wind with a frequency closer to the inertial frequency generates stronger inertial oscillations. For a diurnal wind, the induced inertial oscillation is dependent on latitude and is most significant at 30 °. This relationship is also applied to examine idealized moving cyclones. The inertial oscillation is much stronger on the right-hand side of the cyclone path than on the left-hand side (in the northern hemisphere). This is due to the wind being anti-cyclonic with time on the right-hand side, but cyclonic on the other side. The inertial oscillation varies with the cyclone translation speed. The optimal translation speed generating the greatest inertial oscillations is 2 m/s at the latitude of 10 ° and gradually increases to 6 m/s at the latitude of 30 °.

Thiamine content and thiaminase activity of ten freshwater stocks and one marine stock of alewives

USGS Publications Warehouse

Fitzsimons, J.D.; Williston, B.; Zajicek, J.L.; Tillitt, D.E.; Brown, S.B.; Brown, L.R.; Honeyfield, D.C.; Warner, D.M.; Rudstam, L. G.; Pearsall, W.

2005-01-01

Alewives Alosa pseudoharengus contain thiaminase activity that has been implicated in the development of a thiamine deficiency and associated effects in salmonines of the Great Lakes basin. Little is known about the factors that regulate thiaminase activity in alewives. We sampled alewives of uniform size (60-120 mm) during the summer of 1998 from the Gulf of St. Lawrence, seven of New York's Finger Lakes, one inland lake in Ontario, and two Great Lakes to assess possible relationships among thiamine, lipid content, fish abundance, lake morphometry, lake productivity, freshwater residency, and thiaminase activity. Thiaminase activity varied significantly among the 11 locations but was unrelated to thiamine concentration, which did not vary significantly. Alewife thiaminase activity in the Finger Lakes was negatively related to lipid content and positively related to measures of lake size (e.g., area, volume, and maximum depth). Activity in the one marine stock sampled in the Gulf of St. Lawrence was comparable to the highest values observed in the 10 freshwater stocks examined. Variation in alewife thiaminase activity has the potential to affect the extent of a thiamine deficiency associated with salmonines who feed on alewives as well as the viability of their offspring.

Public Health Significance of Neuroticism

PubMed Central

Lahey, Benjamin B.

2009-01-01

The personality trait of neuroticism refers to relatively stable tendencies to respond with negative emotions to threat, frustration, or loss. Individuals in the population vary markedly on this trait, ranging from frequent and intense emotional reactions to minor challenges to little emotional reaction even in the face of significant difficulties. Although not widely appreciated, there is growing evidence that neuroticism is a psychological trait of profound public health significance. Neuroticism is a robust correlate and predictor of many different mental and physical disorders, comorbidity among them, and the frequency of mental and general health service use. Indeed, neuroticism apparently is a predictor of the quality and longevity of our lives. Achieving a full understanding of the nature and origins of neuroticism, and the mechanisms through which neuroticism is linked to mental and physical disorders, should be a top priority for research. Knowing why neuroticism predicts such a wide variety of seemingly diverse outcomes should lead to improved understanding of commonalities among those outcomes and improved strategies for preventing them. PMID:19449983

Honeybee Odometry: Performance in Varying Natural Terrain

PubMed Central

Tautz, Juergen; Zhang, Shaowu; Spaethe, Johannes; Brockmann, Axel; Si, Aung

2004-01-01

Recent studies have shown that honeybees flying through short, narrow tunnels with visually textured walls perform waggle dances that indicate a much greater flight distance than that actually flown. These studies suggest that the bee's “odometer” is driven by the optic flow (image motion) that is experienced during flight. One might therefore expect that, when bees fly to a food source through a varying outdoor landscape, their waggle dances would depend upon the nature of the terrain experienced en route. We trained honeybees to visit feeders positioned along two routes, each 580 m long. One route was exclusively over land. The other was initially over land, then over water and, finally, again over land. Flight over water resulted in a significantly flatter slope of the waggle-duration versus distance regression, compared to flight over land. The mean visual contrast of the scenes was significantly greater over land than over water. The results reveal that, in outdoor flight, the honeybee's odometer does not run at a constant rate; rather, the rate depends upon the properties of the terrain. The bee's perception of distance flown is therefore not absolute, but scene-dependent. These findings raise important and interesting questions about how these animals navigate reliably. PMID:15252454

The response of cortical neurons to in vivo-like input current: theory and experiment: II. Time-varying and spatially distributed inputs.

PubMed

Giugliano, Michele; La Camera, Giancarlo; Fusi, Stefano; Senn, Walter

2008-11-01

The response of a population of neurons to time-varying synaptic inputs can show a rich phenomenology, hardly predictable from the dynamical properties of the membrane's inherent time constants. For example, a network of neurons in a state of spontaneous activity can respond significantly more rapidly than each single neuron taken individually. Under the assumption that the statistics of the synaptic input is the same for a population of similarly behaving neurons (mean field approximation), it is possible to greatly simplify the study of neural circuits, both in the case in which the statistics of the input are stationary (reviewed in La Camera et al. in Biol Cybern, 2008) and in the case in which they are time varying and unevenly distributed over the dendritic tree. Here, we review theoretical and experimental results on the single-neuron properties that are relevant for the dynamical collective behavior of a population of neurons. We focus on the response of integrate-and-fire neurons and real cortical neurons to long-lasting, noisy, in vivo-like stationary inputs and show how the theory can predict the observed rhythmic activity of cultures of neurons. We then show how cortical neurons adapt on multiple time scales in response to input with stationary statistics in vitro. Next, we review how it is possible to study the general response properties of a neural circuit to time-varying inputs by estimating the response of single neurons to noisy sinusoidal currents. Finally, we address the dendrite-soma interactions in cortical neurons leading to gain modulation and spike bursts, and show how these effects can be captured by a two-compartment integrate-and-fire neuron. Most of the experimental results reviewed in this article have been successfully reproduced by simple integrate-and-fire model neurons.

Classical-quantum arbitrarily varying wiretap channel: Secret message transmission under jamming attacks

NASA Astrophysics Data System (ADS)

Boche, Holger; Cai, Minglai; Deppe, Christian; Nötzel, Janis

2017-10-01

We analyze arbitrarily varying classical-quantum wiretap channels. These channels are subject to two attacks at the same time: one passive (eavesdropping) and one active (jamming). We elaborate on our previous studies [H. Boche et al., Quantum Inf. Process. 15(11), 4853-4895 (2016) and H. Boche et al., Quantum Inf. Process. 16(1), 1-48 (2016)] by introducing a reduced class of allowable codes that fulfills a more stringent secrecy requirement than earlier definitions. In addition, we prove that non-symmetrizability of the legal link is sufficient for equality of the deterministic and the common randomness assisted secrecy capacities. Finally, we focus on analytic properties of both secrecy capacities: We completely characterize their discontinuity points and their super-activation properties.

Activity and physiological significance of the pleopods in the respiration of Callianassa californiensis (Dana) (Crustacea: Thalassinidea).

PubMed

Torres, J J; Gluck, D L; Childress, J J

1977-02-01

1. The pleopods of C. californiensis, a potential site for extrabranchial oxygen exchange, do not contribute significantly to oxygen consumption. 2. C. californiensis has a gill surface area of 4.13 +/- 0.72 cm2/g wet body weight, the lowest value yet reported for a totally aquatic crustacean. 3. C. californiensis, when placed in simulated burrow conditions, regulates the PO2 very loosely in its immediate microhabitat, using its pleopods. 4. Field studies of pH and PO2 values in burrows of C. californiensis indicate that animal movement may play a large part in water exchange between the surface and burrow. 5. Activity studies suggest that oxygen is not critical to C. californiensis on a short term basis. Perception of oxygen after long deprivation may signal the possibility of renewed feeding and activity at the surface of its burrow.

Mediation analysis with time varying exposures and mediators

PubMed Central

VanderWeele, Tyler J.; Tchetgen Tchetgen, Eric J.

2016-01-01

Summary In this paper we consider causal mediation analysis when exposures and mediators vary over time. We give non-parametric identification results, discuss parametric implementation, and also provide a weighting approach to direct and indirect effects based on combining the results of two marginal structural models. We also discuss how our results give rise to a causal interpretation of the effect estimates produced from longitudinal structural equation models. When there are time-varying confounders affected by prior exposure and mediator, natural direct and indirect effects are not identified. However, we define a randomized interventional analogue of natural direct and indirect effects that are identified in this setting. The formula that identifies these effects we refer to as the “mediational g-formula.” When there is no mediation, the mediational g-formula reduces to Robins’ regular g-formula for longitudinal data. When there are no time-varying confounders affected by prior exposure and mediator values, then the mediational g-formula reduces to a longitudinal version of Pearl’s mediation formula. However, the mediational g-formula itself can accommodate both mediation and time-varying confounders and constitutes a general approach to mediation analysis with time-varying exposures and mediators. PMID:28824285

Epistemological and methodological significance of quantitative studies of psychomotor activity for the explanation of clinical depression.

PubMed

Terziivanova, Petya; Haralanov, Svetlozar

2012-12-01

Psychomotor disturbances have been regarded as cardinal symptoms of depression for centuries and their objective assessment may have predictive value with respect to the severity of clinical depression, treatment outcome and prognosis of the affective disorder. Montgomery-Åsberg Depression Rating Scale (MADRS) and Hamilton Rating Scale for Anxiety (HAM-A). Psychomotor indicators of activity and reactivity were objectively recorded and measured by means of computerized ultrasonographic craniocorpography. We found a statistically significant correlation between disturbances in psychomotor indicators and MADRS total score (r = 0.4; P < 0.0001). The severity of HAM-A total score had no statistically significant correlation with psychomotor indicators (P > 0.05). We found that different items of MADRS and HAM-A correlated with psychomotor disturbances of different strength and significance. Objectively, measured psychomotor retardation was associated with greater severity of depressive symptoms assessed at the clinical level. Integration between different methods is needed in order to improve understanding of the psychopathology and the neurobiology of a disputable diagnosis such as clinical depression. © 2012 Blackwell Publishing Ltd.

Sleep duration varies as a function of glutamate and GABA in rat pontine reticular formation.

PubMed

Watson, Christopher J; Lydic, Ralph; Baghdoyan, Helen A

2011-08-01

The oral part of the pontine reticular formation (PnO) is a component of the ascending reticular activating system and plays a role in the regulation of sleep and wakefulness. The PnO receives glutamatergic and GABAergic projections from many brain regions that regulate behavioral state. Indirect, pharmacological evidence has suggested that glutamatergic and GABAergic signaling within the PnO alters traits that characterize wakefulness and sleep. No previous studies have simultaneously measured endogenous glutamate and GABA from rat PnO in relation to sleep and wakefulness. The present study utilized in vivo microdialysis coupled on-line to capillary electrophoresis with laser-induced fluorescence to test the hypothesis that concentrations of glutamate and GABA in the PnO vary across the sleep/wake cycle. Concentrations of glutamate and GABA were significantly higher during wakefulness than during non-rapid eye movement sleep and rapid eye movement sleep. Regression analysis revealed that decreases in glutamate and GABA accounted for a significant portion of the variance in the duration of non-rapid eye movement sleep and rapid eye movement sleep episodes. These data provide novel support for the hypothesis that endogenous glutamate and GABA in the PnO contribute to the regulation of sleep duration. © 2011 The Authors. Journal of Neurochemistry © 2011 International Society for Neurochemistry.

Influence of zinc on bacterial populations and their proteolytic enzyme activities in freshwater environments: a cross-site comparison.

PubMed

Rasmussen, Lauren; Olapade, Ola A

2016-04-01

Temporal responses of indigenous bacterial populations and proteolytic enzyme (i.e., aminopeptidase) activities in the bacterioplankton assemblages from 3 separate freshwater environments were examined after exposure to various zinc (Zn) concentrations under controlled microcosm conditions. Zn concentrations (ranging from 0 to 10 μmol/L) were added to water samples collected from the Kalamazoo River, Rice Creek, and Huron River and examined for bacterial abundance and aminopeptidase activities at various time intervals over a 48 h incubation period in the dark. The results showed that the Zn concentrations did not significantly influence total bacterial counts directly; however, aminopeptidase activities varied significantly to increasing zinc treatments over time. Also, analysis of variance and linear regression analyses revealed significant positive relationships between bacterial numbers and their hydrolytic enzyme activities, suggesting that both probably co-vary with increasing Zn concentrations in aquatic systems. The results from this study serve as additional evidence of the ecological role of Zn as an extracellular peptidase cofactor on the dynamics of bacterial assemblages in aquatic environments.

Premixed Edge-Flames in Spatially-Varying Straining Flows

NASA Technical Reports Server (NTRS)

Liu, Jian-Bang; Ronney, Paul D.

1999-01-01

Flames subject to temporally and spatially uniform hydrodynamic strain are frequently used to model the local interactions of flame fronts with turbulent flow fields (Williams, 1985; Peters, 1986; Bradley, 1992). The applicability of laminar flamelet models in strongly turbulent flows have been questioned recently (Shay and Ronney, 1998) because in turbulent flows the strain rate (sigma) changes at rates comparable to sigma itself and the scale over which the flame front curvature and sigma changes is comparable to the curvature scale itself. Therefore quasi-static, local models of turbulent strain and curvature effects on laminar flamelets may not be accurate under conditions where the strain and curvature effects are most significant. The purpose of this study is to examine flames in spatially-varying strain and compare their properties to those of uniformly strained flames.

Model microswimmers in channels with varying cross section

NASA Astrophysics Data System (ADS)

Malgaretti, Paolo; Stark, Holger

2017-05-01

We study different types of microswimmers moving in channels with varying cross section and thereby interacting hydrodynamically with the channel walls. Starting from the Smoluchowski equation for a dilute suspension, for which interactions among swimmers can be neglected, we derive analytic expressions for the lateral probability distribution between plane channel walls. For weakly corrugated channels, we extend the Fick-Jacobs approach to microswimmers and thereby derive an effective equation for the probability distribution along the channel axis. Two regimes arise dominated either by entropic forces due to the geometrical confinement or by the active motion. In particular, our results show that the accumulation of microswimmers at channel walls is sensitive to both the underlying swimming mechanism and the geometry of the channels. Finally, for asymmetric channel corrugation, our model predicts a rectification of microswimmers along the channel, the strength and direction of which strongly depends on the swimmer type.

Optical waveguide device with an adiabatically-varying width

DOEpatents

Watts,; Michael R. , Nielson; Gregory, N [Albuquerque, NM

2011-05-10

Optical waveguide devices are disclosed which utilize an optical waveguide having a waveguide bend therein with a width that varies adiabatically between a minimum value and a maximum value of the width. One or more connecting members can be attached to the waveguide bend near the maximum value of the width thereof to support the waveguide bend or to supply electrical power to an impurity-doped region located within the waveguide bend near the maximum value of the width. The impurity-doped region can form an electrical heater or a semiconductor junction which can be activated with a voltage to provide a variable optical path length in the optical waveguide. The optical waveguide devices can be used to form a tunable interferometer (e.g. a Mach-Zehnder interferometer) which can be used for optical modulation or switching. The optical waveguide devices can also be used to form an optical delay line.

Habitat degradation affects the summer activity of polar bears

USGS Publications Warehouse

Ware, Jasmine V.; Rode, Karyn D.; Bromaghin, Jeffrey F.; Douglas, David C.; Wilson, Ryan R.; Regehr, Eric V.; Amstrup, Steven C.; Durner, George M.; Pagano, Anthony M.; Olson, Jay; Robbins, Charles T.; Jansen, Heiko T

2017-01-01

Understanding behavioral responses of species to environmental change is critical to forecasting population-level effects. Although climate change is significantly impacting species’ distributions, few studies have examined associated changes in behavior. Polar bear (Ursus maritimus) subpopulations have varied in their near-term responses to sea ice decline. We examined behavioral responses of two adjacent subpopulations to changes in habitat availability during the annual sea ice minimum using activity data. Location and activity sensor data collected from 1989 to 2014 for 202 adult female polar bears in the Southern Beaufort Sea (SB) and Chukchi Sea (CS) subpopulations were used to compare activity in three habitat types varying in prey availability: (1) land; (2) ice over shallow, biologically productive waters; and (3) ice over deeper, less productive waters. Bears varied activity across and within habitats with the highest activity at 50–75% sea ice concentration over shallow waters. On land, SB bears exhibited variable but relatively high activity associated with the use of subsistence-harvested bowhead whale carcasses, whereas CS bears exhibited low activity consistent with minimal feeding. Both subpopulations had fewer observations in their preferred shallow-water sea ice habitats in recent years, corresponding with declines in availability of this substrate. The substantially higher use of marginal habitats by SB bears is an additional mechanism potentially explaining why this subpopulation has experienced negative effects of sea ice loss compared to the still-productive CS subpopulation. Variability in activity among, and within, habitats suggests that bears alter their behavior in response to habitat conditions, presumably in an attempt to balance prey availability with energy costs.

Robust check loss-based variable selection of high-dimensional single-index varying-coefficient model

NASA Astrophysics Data System (ADS)

Song, Yunquan; Lin, Lu; Jian, Ling

2016-07-01

Single-index varying-coefficient model is an important mathematical modeling method to model nonlinear phenomena in science and engineering. In this paper, we develop a variable selection method for high-dimensional single-index varying-coefficient models using a shrinkage idea. The proposed procedure can simultaneously select significant nonparametric components and parametric components. Under defined regularity conditions, with appropriate selection of tuning parameters, the consistency of the variable selection procedure and the oracle property of the estimators are established. Moreover, due to the robustness of the check loss function to outliers in the finite samples, our proposed variable selection method is more robust than the ones based on the least squares criterion. Finally, the method is illustrated with numerical simulations.

Root and Rhizosphere Bacterial Phosphatase Activity Varies with Tree Species and Soil Phosphorus Availability in Puerto Rico Tropical Forest

PubMed Central

Cabugao, Kristine G.; Timm, Collin M.; Carrell, Alyssa A.; Childs, Joanne; Lu, Tse-Yuan S.; Pelletier, Dale A.; Weston, David J.; Norby, Richard J.

2017-01-01

Tropical forests generally occur on highly weathered soils that, in combination with the immobility of phosphorus (P), often result in soils lacking orthophosphate, the form of P most easily metabolized by plants and microbes. In these soils, mineralization of organic P can be the major source for orthophosphate. Both plants and microbes encode for phosphatases capable of mineralizing a range of organic P compounds. However, the activity of these enzymes depends on several edaphic factors including P availability, tree species, and microbial communities. Thus, phosphatase activity in both roots and the root microbial community constitute an important role in P mineralization and P nutrient dynamics that are not well studied in tropical forests. To relate phosphatase activity of roots and bacteria in tropical forests, we measured phosphatase activity in roots and bacterial isolates as well as bacterial community composition from the rhizosphere. Three forests in the Luquillo Mountains of Puerto Rico were selected to represent a range of soil P availability as measured using the resin P method. Within each site, a minimum of three tree species were chosen to sample. Root and bacterial phosphatase activity were both measured using a colorimetric assay with para-nitrophenyl phosphate as a substrate for the phosphomonoesterase enzyme. Both root and bacterial phosphatase were chiefly influenced by tree species. Though tree species was the only significant factor in root phosphatase activity, there was a negative trend between soil P availability and phosphatase activity in linear regressions of average root phosphatase and resin P. Permutational multivariate analysis of variance of bacterial community composition based on 16S amplicon sequencing indicated that bacterial composition was strongly controlled by soil P availability (p-value < 0.05). These results indicate that although root and bacterial phosphatase activity were influenced by tree species; bacterial

Root and Rhizosphere Bacterial Phosphatase Activity Varies with Tree Species and Soil Phosphorus Availability in Puerto Rico Tropical Forest.

PubMed

Cabugao, Kristine G; Timm, Collin M; Carrell, Alyssa A; Childs, Joanne; Lu, Tse-Yuan S; Pelletier, Dale A; Weston, David J; Norby, Richard J

2017-01-01

Tropical forests generally occur on highly weathered soils that, in combination with the immobility of phosphorus (P), often result in soils lacking orthophosphate, the form of P most easily metabolized by plants and microbes. In these soils, mineralization of organic P can be the major source for orthophosphate. Both plants and microbes encode for phosphatases capable of mineralizing a range of organic P compounds. However, the activity of these enzymes depends on several edaphic factors including P availability, tree species, and microbial communities. Thus, phosphatase activity in both roots and the root microbial community constitute an important role in P mineralization and P nutrient dynamics that are not well studied in tropical forests. To relate phosphatase activity of roots and bacteria in tropical forests, we measured phosphatase activity in roots and bacterial isolates as well as bacterial community composition from the rhizosphere. Three forests in the Luquillo Mountains of Puerto Rico were selected to represent a range of soil P availability as measured using the resin P method. Within each site, a minimum of three tree species were chosen to sample. Root and bacterial phosphatase activity were both measured using a colorimetric assay with para-nitrophenyl phosphate as a substrate for the phosphomonoesterase enzyme. Both root and bacterial phosphatase were chiefly influenced by tree species. Though tree species was the only significant factor in root phosphatase activity, there was a negative trend between soil P availability and phosphatase activity in linear regressions of average root phosphatase and resin P. Permutational multivariate analysis of variance of bacterial community composition based on 16S amplicon sequencing indicated that bacterial composition was strongly controlled by soil P availability ( p -value < 0.05). These results indicate that although root and bacterial phosphatase activity were influenced by tree species; bacterial

Dynamic Divisive Normalization Predicts Time-Varying Value Coding in Decision-Related Circuits

PubMed Central

LoFaro, Thomas; Webb, Ryan; Glimcher, Paul W.

2014-01-01

Normalization is a widespread neural computation, mediating divisive gain control in sensory processing and implementing a context-dependent value code in decision-related frontal and parietal cortices. Although decision-making is a dynamic process with complex temporal characteristics, most models of normalization are time-independent and little is known about the dynamic interaction of normalization and choice. Here, we show that a simple differential equation model of normalization explains the characteristic phasic-sustained pattern of cortical decision activity and predicts specific normalization dynamics: value coding during initial transients, time-varying value modulation, and delayed onset of contextual information. Empirically, we observe these predicted dynamics in saccade-related neurons in monkey lateral intraparietal cortex. Furthermore, such models naturally incorporate a time-weighted average of past activity, implementing an intrinsic reference-dependence in value coding. These results suggest that a single network mechanism can explain both transient and sustained decision activity, emphasizing the importance of a dynamic view of normalization in neural coding. PMID:25429145

Overexpression of PAD1 and FDC1 results in significant cinnamic acid decarboxylase activity in Saccharomyces cerevisiae.

PubMed

Richard, Peter; Viljanen, Kaarina; Penttilä, Merja

2015-01-01

The S. cerevisiae PAD1 gene had been suggested to code for a cinnamic acid decarboxylase, converting trans-cinnamic acid to styrene. This was suggested for the reason that the over-expression of PAD1 resulted in increased tolerance toward cinnamic acid, up to 0.6 mM. We show that by over-expression of the PAD1 together with the FDC1 the cinnamic acid decarboxylase activity can be increased significantly. The strain over-expressing PAD1 and FDC1 tolerated cinnamic acid concentrations up to 10 mM. The cooperation of Pad1p and Fdc1p is surprising since the PAD1 has a mitochondrial targeting sequence and the FDC1 codes for a cytosolic protein. The cinnamic acid decarboxylase activity was also seen in the cell free extract. The activity was 0.019 μmol per minute and mg of extracted protein. The overexpression of PAD1 and FDC1 resulted also in increased activity with the hydroxycinnamic acids ferulic acid, p-coumaric acid and caffeinic acid. This activity was not seen when FDC1 was overexpressed alone. An efficient cinnamic acid decarboxylase is valuable for the genetic engineering of yeast strains producing styrene. Styrene can be produced from endogenously produced L-phenylalanine which is converted by a phenylalanine ammonia lyase to cinnamic acid and then by a decarboxylase to styrene.

Analytical treatment of self-phase-modulation beyond the slowly varying envelope approximation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Syrchin, M.S.; Zheltikov, A.M.; International Laser Center, M.V. Lomonosov Moscow State University, 119899 Moscow

Analytical treatment of the self-phase-modulation of an ultrashort light pulse is extended beyond the slowly varying envelope approximation. The resulting wave equation is modified to include corrections to self-phase-modulation due to higher-order spatial and temporal derivatives. Analytical solutions are found in the limiting regimes of high nonlinearities and very short pulses. Our results reveal features that can significantly impact both pulse shape and the evolution of the phase.

Physiological responses and lipid storage of the coral Lophelia pertusa at varying food density.

PubMed

Baussant, Thierry; Nilsen, Marianne; Ravagnan, Elisa; Westerlund, Stig; Ramanand, Sreerekha

2017-01-01

Despite the importance of the cold-water coral Lophelia pertusa to deep-sea reef ecosystem functioning, current knowledge of key physiological responses to available food resources is scarce. Scenarios with varying food density may help to understand how corals deal with seasonal variations in the dark ocean and might be used to study consequences of anthropogenic activities potentially affecting food availability. Thus, the physiological responses of L. pertusa to varying food (Artemia salina nauplii) concentration, ranging from 20% to 300% of carbon equivalent turned over by basal coral respiration, were investigated. A starvation group was also included. Measurements of respiration, growth, mucus production, and energy reserves (storage fatty acids) were performed at several time intervals over 26 weeks. In general, data showed a stronger effect of experimental time on measured responses, but no significant influence of food density treatment. In starved corals, respiration rate declined to 52% of initial respiration, while skeleton growth rate was maintained at the same rate as Artemia-fed corals throughout the investigation. Mucus production measured as the sum of dissolved organic carbon (DOC) and particulate organic carbon (POC) was also similar across food treatments, but POC production exceeded that of DOC at the highest food density. No marked effect was observed on storage fatty acids. These results confirm that L. pertusa is highly resilient to environmental conditions with suboptimal food densities over a time scale of months. Regulation of several physiological processes, including respiration and mucus production, possibly in combination with an opportunistic feeding strategy, contributed to this tolerance to maintain viable corals. Thus, it appears that L. pertusa is well adapted to life in the deep sea.

Investigating the Relationship between Instructors' Use of Active-Learning Strategies and Students' Conceptual Understanding and Affective Changes in Introductory Biology: A Comparison of Two Active-Learning Environments.

PubMed

Cleveland, Lacy M; Olimpo, Jeffrey T; DeChenne-Peters, Sue Ellen

2017-01-01

In response to calls for reform in undergraduate biology education, we conducted research examining how varying active-learning strategies impacted students' conceptual understanding, attitudes, and motivation in two sections of a large-lecture introductory cell and molecular biology course. Using a quasi-experimental design, we collected quantitative data to compare participants' conceptual understanding, attitudes, and motivation in the biological sciences across two contexts that employed different active-learning strategies and that were facilitated by unique instructors. Students participated in either graphic organizer/worksheet activities or clicker-based case studies. After controlling for demographic and presemester affective differences, we found that students in both active-learning environments displayed similar and significant learning gains. In terms of attitudinal and motivational data, significant differences were observed for two attitudinal measures. Specifically, those students who had participated in graphic organizer/worksheet activities demonstrated more expert-like attitudes related to their enjoyment of biology and ability to make real-world connections. However, all motivational and most attitudinal data were not significantly different between the students in the two learning environments. These data reinforce the notion that active learning is associated with conceptual change and suggests that more research is needed to examine the differential effects of varying active-learning strategies on students' attitudes and motivation in the domain. © 2017 L. M. Cleveland et al. CBE—Life Sciences Education © 2017 The American Society for Cell Biology. This article is distributed by The American Society for Cell Biology under license from the author(s). It is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

Ectomycorrhizal Fungal Communities and Enzymatic Activities Vary across an Ecotone between a Forest and Field.

PubMed

Rúa, Megan A; Moore, Becky; Hergott, Nicole; Van, Lily; Jackson, Colin R; Hoeksema, Jason D

2015-08-28

Extracellular enzymes degrade macromolecules into soluble substrates and are important for nutrient cycling in soils, where microorganisms, such as ectomycorrhizal (ECM) fungi, produce these enzymes to obtain nutrients. Ecotones between forests and fields represent intriguing arenas for examining the effect of the environment on ECM community structure and enzyme activity because tree maturity, ECM composition, and environmental variables may all be changing simultaneously. We studied the composition and enzymatic activity of ECM associated with loblolly pine (Pinus taeda) across an ecotone between a forest where P. taeda is established and an old field where P. taeda saplings had been growing for <5 years. ECM community and environmental characteristics influenced enzyme activity in the field, indicating that controls on enzyme activity may be intricately linked to the ECM community, but this was not true in the forest. Members of the Russulaceae were associated with increased phenol oxidase activity and decreased peroxidase activity in the field. Members of the Atheliaceae were particularly susceptible to changes in their abiotic environment, but this did not mediate differences in enzyme activity. These results emphasize the complex nature of factors that dictate the distribution of ECM and activity of their enzymes across a habitat boundary.

Do physicians' attitudes toward implantable cardioverter defibrillator therapy vary by patient age, gender, or race?

PubMed

Al-Khatib, Sana M; Sanders, Gillian D; O'Brien, Sean M; Matlock, Daniel; Zimmer, Louise O; Masoudi, Frederick A; Peterson, Eric

2011-01-01

Implantable cardioverter defibrillator (ICD) therapy improves survival of patients with systolic heart failure. We assessed whether physicians' recommendation for ICD therapy varies as a function of patient age, gender, race, and physician's specialty. We surveyed a random sample (n = 9969) of U.S. physicians who are active members of the American College of Cardiology (ACC). We asked participants about their likelihood to recommend ICD therapy in 4 clinical scenarios that randomly varied patient age, gender, race, and ICD indication (guideline Class I, Class IIa, Class III, and Class I in a noncompliant patient). Responses were received from 1210 physicians (response rate 12%), of whom 1127 met the study inclusion criteria. Responders and nonresponders had similar demographics. In responding to hypothetical clinical scenarios, physicians were less likely to recommend an ICD to older patients (≥80 vs 50 years) (P < 0.01) but were unaffected by gender or race for all class indications. Compared with non-electrophysiologists (EPs), EPs were significantly more likely to recommend an ICD for a Class I indication (92.4% vs 81.4%; P < 0.01), but they were not more likely to offer an ICD for a Class III indication (0.4% vs 0.6%; P = 0.95). Based on survey responses, physicians were equally willing to offer an ICD to men and women and to whites and blacks, but were less likely to offer an ICD to an older patient even when indicated by practice guidelines. Electrophysiologists (EPs) more often adhered to practice guideline recommendations on ICD therapy compared with non-EPs. ©2011, Wiley Periodicals, Inc.

Acute response of hypophysiotropic thyrotropin releasing hormone neurons and thyrotropin release to behavioral paradigms producing varying intensities of stress and physical activity.

PubMed

Gutiérrez-Mariscal, Mariana; Sánchez, Edith; García-Vázquez, Arlene; Rebolledo-Solleiro, Daniela; Charli, Jean-Louis; Joseph-Bravo, Patricia

2012-11-10

The activity of the hypothalamus-pituitary-thyroid (HPT) axis is essential for energy homeostasis and is differentially modulated by physical and by psychological stress. Contradictory effects of stressful behavioral paradigms on TSH or thyroid hormone release are due to type, length and controllability of the stressor. We hypothesized that an additional determinant of the activity of the HPT axis is the energy demand due to physical activity. We thus evaluated the response of thyrotropin releasing hormone (TRH) neurons of the hypothalamic paraventricular nucleus (PVN) in Wistar male rats submitted to the elevated plus maze (EPM), the open field test (OFT), or restraint, and sacrificed within 1h after test completion; the response to OFT was compared during light (L) or dark (D) phases. Locomotion and anxiety behaviors were similar if animals were tested in L or D phases but their relation to the biochemical parameters differed. All paradigms increased serum corticosterone concentration; the levels of corticotropin releasing hormone receptor 1 and of glucocorticoid receptor (GR) mRNAs in the PVN were enhanced after restraint or OFT-L. Levels of proTRH mRNA increased in the PVN after exposure to EPM-L or OFT-D; serum levels of thyrotropin (TSH) and T(4) only after OFT-D. In contrast, restraint decreased TRH mRNA and serum TSH levels, while it increased TRH content in the mediobasal hypothalamus, implying reduced release. Expression of proTRH in the PVN varied proportionally to the degree of locomotion in OFT-D, while inversely to anxiety in the EPM-L, and to corticosterone in EPM-L and OFT-D. TRH mRNA levels were analyzed by in situ hybridization in the rostral, middle and caudal zones of the PVN in response to OFT-D; they increased in the middle PVN, where most TRH hypophysiotropic neurons reside; levels correlated positively with the velocity attained in the periphery of the OF and negatively, with anxiety. Variations of serum TSH levels correlated positively with

Effects of Varying Proportions of Glass on Reflectance Spectra of HED Polymict Breccias

NASA Technical Reports Server (NTRS)

Buchanan, P. C.; Reddy, V; LeCorre, L.; Cloutis, E. A.; Mann, P.; Le, L.

2014-01-01

Some meteorites contain significant amounts of glass, which, in most cases, probably results from impact processes on parent bodies.. Yamato 82202 is an example of one of the unequilibrated eucrites that contains significant proportions of impact glass distributed as veins throughout the meteorite. In other cases, fragments of glass are distributed throughout polymict breccias. For example, the polymict eucrite EET 87509 contains rare angular fragments of devitrified glass. Proportions of glass in most of these meteorites and in lithic clasts within these meteorites may vary locally from small amounts (less than one percent) to much larger amounts (subequal proportions of glass and mineral material). For example, some fragments within the South African polymict eucrite Macibini contain approximately 50% glass. The presence of these variable proportions of meteorite glass confirm the increased recognition that impact processes played an important role in the histories of asteroidal bodies. This study attempts to quantify the effects of a glass component on reflectance spectra by analyzing in the laboratory mixtures of varying proportions of a well-characterized HED polymict breccia and glass derived by melting a bulk sample of that breccia.

Failure Modes in Capacitors When Tested Under a Time-Varying Stress

NASA Technical Reports Server (NTRS)

Liu, David (Donhang)

2011-01-01

Power-on failure has been the prevalent failure mechanism for solid tantalum capacitors in decoupling applications. A surge step stress test (SSST) has been previously applied to identify the critical stress level of a capacitor batch to give some predictability to the power-on failure mechanism [1]. But SSST can also be viewed as an electrically destructive test under a time-varying stress (voltage). It consists of rapidly charging the capacitor with incremental voltage increases, through a low resistance in series, until the capacitor under test is electrically shorted. When the reliability of capacitors is evaluated, a highly accelerated life test (HALT) is usually adopted since it is a time-efficient method of determining the failure mechanism; however, a destructive test under a time-varying stress such as SSST is even more time efficient. It usually takes days or weeks to complete a HALT test, but it only takes minutes for a time-varying stress test to produce failures. The advantage of incorporating a specific time-varying stress profile into a statistical model is significant in providing an alternative life test method for quickly revealing the failure mechanism in capacitors. In this paper, a time-varying stress that mimics a typical SSST has been incorporated into the Weibull model to characterize the failure mechanism in different types of capacitors. The SSST circuit and transient conditions for correctly surge testing capacitors are discussed. Finally, the SSST was applied for testing Ta capacitors, polymer aluminum capacitors (PA capacitors), and multi-layer ceramic (MLC) capacitors with both precious metal electrodes (PME) and base metal electrodes (BME). The test results are found to be directly associated with the dielectric layer breakdown in Ta and PA capacitors and are independent of the capacitor values, the way the capacitors were built, and the capacitors manufacturers. The test results also show that MLC capacitors exhibit surge breakdown

Ectomycorrhizal Fungal Communities and Enzymatic Activities Vary across an Ecotone between a Forest and Field

PubMed Central

Rúa, Megan A.; Moore, Becky; Hergott, Nicole; Van, Lily; Jackson, Colin R.; Hoeksema, Jason D.

2015-01-01

Extracellular enzymes degrade macromolecules into soluble substrates and are important for nutrient cycling in soils, where microorganisms, such as ectomycorrhizal (ECM) fungi, produce these enzymes to obtain nutrients. Ecotones between forests and fields represent intriguing arenas for examining the effect of the environment on ECM community structure and enzyme activity because tree maturity, ECM composition, and environmental variables may all be changing simultaneously. We studied the composition and enzymatic activity of ECM associated with loblolly pine (Pinus taeda) across an ecotone between a forest where P. taeda is established and an old field where P. taeda saplings had been growing for <5 years. ECM community and environmental characteristics influenced enzyme activity in the field, indicating that controls on enzyme activity may be intricately linked to the ECM community, but this was not true in the forest. Members of the Russulaceae were associated with increased phenol oxidase activity and decreased peroxidase activity in the field. Members of the Atheliaceae were particularly susceptible to changes in their abiotic environment, but this did not mediate differences in enzyme activity. These results emphasize the complex nature of factors that dictate the distribution of ECM and activity of their enzymes across a habitat boundary. PMID:29376908

Time Varying Compensator Design for Reconfigurable Structures Using Non-Collocated Feedback

NASA Technical Reports Server (NTRS)

Scott, Michael A.

1996-01-01

Analysis and synthesis tools are developed to improved the dynamic performance of reconfigurable nonminimum phase, nonstrictly positive real-time variant systems. A novel Spline Varying Optimal (SVO) controller is developed for the kinematic nonlinear system. There are several advantages to using the SVO controller, in which the spline function approximates the system model, observer, and controller gain. They are: The spline function approximation is simply connected, thus the SVO controller is more continuous than traditional gain scheduled controllers when implemented on a time varying plant; ft is easier for real-time implementations in storage and computational effort; where system identification is required, the spline function requires fewer experiments, namely four experiments; and initial startup estimator transients are eliminated. The SVO compensator was evaluated on a high fidelity simulation of the Shuttle Remote Manipulator System. The SVO controller demonstrated significant improvement over the present arm performance: (1) Damping level was improved by a factor of 3; and (2) Peak joint torque was reduced by a factor of 2 following Shuttle thruster firings.

Activated fluid transport regulates bacterial-epithelial interactions and significantly shifts the murine colonic microbiome

PubMed Central

Keely, Simon; Kelly, Caleb J.; Weissmueller, Thomas; Burgess, Adrianne; Wagner, Brandie D.; Robertson, Charles E.; Harris, J. Kirk; Colgan, Sean P.

2012-01-01

Within the intestinal mucosa, epithelial cells serve multiple functions to partition the lumen from the lamina propria. As part of their natural function, intestinal epithelial cells actively transport electrolytes with passive water movement as a mechanism for mucosal hydration. Here, we hypothesized that electrogenic Cl- secretion, and associated mucosal hydration, influences bacterial-epithelial interactions and significantly influences the composition of the intestinal microbiota. An initial screen of different epithelial secretagogues identified lubiprostone as the most potent agonist for which to define these principles. In in vitro studies using cultured T84 cells, lubiprostone decreased E. coli translocation in a concentration-dependent manner (p < 0.001) and decreased S. typhimurium internalization and translocation by as much as 71 ± 6% (p < 0.01). Such decreases in bacterial translocation were abolished by inhibition of electrogenic Cl- secretion and water transport using the Na-K-Cl- antagonist bumetanide (p < 0.01). Extensions of these findings to microbiome analysis in vivo revealed that lubiprostone delivered orally to mice fundamentally shifted the intestinal microbiota, with notable changes within the Firmicutes and Bacteroidetes phyla of resident colonic bacteria. Such findings document a previously unappreciated role for epithelial Cl- secretion and water transport in influencing bacterial-epithelial interactions and suggest that active mucosal hydration functions as a primitive innate epithelial defense mechanism. PMID:22614705

Clinical prognostic significance and pro-metastatic activity of RANK/RANKL via the AKT pathway in endometrial cancer.

PubMed

Wang, Jing; Liu, Yao; Wang, Lihua; Sun, Xiao; Wang, Yudong

2016-02-02

RANK/RANKL plays a key role in metastasis of certain malignant tumors, which makes it a promising target for developing novel therapeutic strategies for cancer. However, the prognostic value and pro-metastatic activity of RANK in endometrial cancer (EC) remain to be determined. Thus, the present study investigated the effect of RANK on the prognosis of EC patients, as well as the pro-metastatic activity of EC cells. The results indicated that those with high expression of RANK showed decreased overall survival and progression-free survival. Statistical analysis revealed the positive correlations between RANK/RANKL expression and metastasis-related factors. Additionally, RANK/RANKL significantly promoted cell migration/invasion via activating AKT/β-catenin/Snail pathway in vitro. However, RANK/RANKL-induced AKT activation could be suppressed after osteoprotegerin (OPG) treatment. Furthermore, the combination of medroxyprogesterone acetate (MPA) and RANKL could in turn attenuate the effect of RANKL alone. Similarly, MPA could partially inhibit the RANK-induced metastasis in an orthotopic mouse model via suppressing AKT/β-catenin/Snail pathway. Therefore, therapeutic inhibition of MPA in RANK/RANKL-induced metastasis was mediated by AKT/β-catenin/Snail pathway both in vitro and in vivo, suggesting a potential target of RANK for gene-based therapy for EC.

Phenoloxidase activity in the infraorder Isoptera: unraveling life-history correlates of immune investment

NASA Astrophysics Data System (ADS)

Rosengaus, Rebeca B.; Reichheld, Jennifer L.

2016-02-01

Within the area of ecological immunology, the quantification of phenoloxidase (PO) activity has been used as a proxy for estimating immune investment. Because termites have unique life-history traits and significant inter-specific differences exist regarding their nesting and foraging habits, comparative studies on PO activity can shed light on the general principles influencing immune investment against the backdrop of sociality, reproductive potential, and gender. We quantified PO activity across four termite species ranging from the phylogenetically basal to the most derived, each with their particular nesting/foraging strategies. Our data indicate that PO activity varies across species, with soil-dwelling termites exhibiting significantly higher PO levels than the above-ground wood nester species which in turn have higher PO levels than arboreal species. Moreover, our comparative approach suggests that pathogenic risks can override reproductive potential as a more important driver of immune investment. No gender-based differences in PO activities were recorded. Although termite PO activity levels vary in accordance with a priori predictions made from life-history theory, our data indicate that nesting and foraging strategies (and their resulting pathogenic pressures) can supersede reproductive potential and other life-history traits in influencing investment in PO. Termites, within the eusocial insects, provide a unique perspective for inferring how different ecological pressures may have influenced immune function in general and their levels of PO activity, in particular.

Does the effect of a school recess intervention on physical activity vary by gender or race? Results from the Ready for Recess pilot study.

PubMed

Siahpush, Mohammad; Huberty, Jennifer L; Beighle, Aaron

2012-01-01

The recess environment in schools has been identified as an integral part of school-based programs to enhance physical activity (PA). The purpose of this study was to report pilot findings on the extent to which the Ready for Recess intervention was associated with a different amount of increase in moderate to vigorous PA (MPVA) during recess and the rest of the school day between girls and boys, and between nonwhites and whites. The Ready for Recess intervention modified the recess environment of schools by providing staff training and recreational equipment. The MPVA levels of 3rd, 4th, and 5th grade students (n = 93) at 2 schools were measured pre- and post-intervention using ActiGraph accelerometers. Multiple regression models with robust variance were utilized to test for the interaction of intervention with gender and race/ethnicity. The intervention was associated with an adjusted increase of 4.7 minutes (P <.001) in moderate/vigorous PA during recess. There was no evidence that this effect varied by gender (P = .944) or race (P = .731). The intervention was also associated with an adjusted increase of 29.6 minutes (P < .001) in moderate/vigorous PA during rest of the school day. While this effect did not vary by gender, there was some evidence (P = .034) that nonwhites benefited more from the intervention than whites. Simple strategies such as staff training and recreational equipment may be an effective way to increase PA in children (despite gender or ethnicity) during recess time as well as during the rest of the school day.

A Novel Time-Varying Spectral Filtering Algorithm for Reconstruction of Motion Artifact Corrupted Heart Rate Signals During Intense Physical Activities Using a Wearable Photoplethysmogram Sensor

PubMed Central

Salehizadeh, Seyed M. A.; Dao, Duy; Bolkhovsky, Jeffrey; Cho, Chae; Mendelson, Yitzhak; Chon, Ki H.

2015-01-01

Accurate estimation of heart rates from photoplethysmogram (PPG) signals during intense physical activity is a very challenging problem. This is because strenuous and high intensity exercise can result in severe motion artifacts in PPG signals, making accurate heart rate (HR) estimation difficult. In this study we investigated a novel technique to accurately reconstruct motion-corrupted PPG signals and HR based on time-varying spectral analysis. The algorithm is called Spectral filter algorithm for Motion Artifacts and heart rate reconstruction (SpaMA). The idea is to calculate the power spectral density of both PPG and accelerometer signals for each time shift of a windowed data segment. By comparing time-varying spectra of PPG and accelerometer data, those frequency peaks resulting from motion artifacts can be distinguished from the PPG spectrum. The SpaMA approach was applied to three different datasets and four types of activities: (1) training datasets from the 2015 IEEE Signal Process. Cup Database recorded from 12 subjects while performing treadmill exercise from 1 km/h to 15 km/h; (2) test datasets from the 2015 IEEE Signal Process. Cup Database recorded from 11 subjects while performing forearm and upper arm exercise. (3) Chon Lab dataset including 10 min recordings from 10 subjects during treadmill exercise. The ECG signals from all three datasets provided the reference HRs which were used to determine the accuracy of our SpaMA algorithm. The performance of the SpaMA approach was calculated by computing the mean absolute error between the estimated HR from the PPG and the reference HR from the ECG. The average estimation errors using our method on the first, second and third datasets are 0.89, 1.93 and 1.38 beats/min respectively, while the overall error on all 33 subjects is 1.86 beats/min and the performance on only treadmill experiment datasets (22 subjects) is 1.11 beats/min. Moreover, it was found that dynamics of heart rate variability can be

A Novel Time-Varying Spectral Filtering Algorithm for Reconstruction of Motion Artifact Corrupted Heart Rate Signals During Intense Physical Activities Using a Wearable Photoplethysmogram Sensor.

PubMed

Salehizadeh, Seyed M A; Dao, Duy; Bolkhovsky, Jeffrey; Cho, Chae; Mendelson, Yitzhak; Chon, Ki H

2015-12-23

Accurate estimation of heart rates from photoplethysmogram (PPG) signals during intense physical activity is a very challenging problem. This is because strenuous and high intensity exercise can result in severe motion artifacts in PPG signals, making accurate heart rate (HR) estimation difficult. In this study we investigated a novel technique to accurately reconstruct motion-corrupted PPG signals and HR based on time-varying spectral analysis. The algorithm is called Spectral filter algorithm for Motion Artifacts and heart rate reconstruction (SpaMA). The idea is to calculate the power spectral density of both PPG and accelerometer signals for each time shift of a windowed data segment. By comparing time-varying spectra of PPG and accelerometer data, those frequency peaks resulting from motion artifacts can be distinguished from the PPG spectrum. The SpaMA approach was applied to three different datasets and four types of activities: (1) training datasets from the 2015 IEEE Signal Process. Cup Database recorded from 12 subjects while performing treadmill exercise from 1 km/h to 15 km/h; (2) test datasets from the 2015 IEEE Signal Process. Cup Database recorded from 11 subjects while performing forearm and upper arm exercise. (3) Chon Lab dataset including 10 min recordings from 10 subjects during treadmill exercise. The ECG signals from all three datasets provided the reference HRs which were used to determine the accuracy of our SpaMA algorithm. The performance of the SpaMA approach was calculated by computing the mean absolute error between the estimated HR from the PPG and the reference HR from the ECG. The average estimation errors using our method on the first, second and third datasets are 0.89, 1.93 and 1.38 beats/min respectively, while the overall error on all 33 subjects is 1.86 beats/min and the performance on only treadmill experiment datasets (22 subjects) is 1.11 beats/min. Moreover, it was found that dynamics of heart rate variability can be

Significant Differences in Pediatric Psychotropic Side Effects: Implications for School Performance

ERIC Educational Resources Information Center

Kubiszyn, Thomas; Mire, Sarah; Dutt, Sonia; Papathopoulos, Katina; Burridge, Andrea Backsheider

2012-01-01

Some side effects (SEs) of increasingly prescribed psychotropic medications can impact student performance in school. SE risk varies, even among drugs from the same class (e.g., antidepressants). Knowing which SEs occur significantly more often than others may enable school psychologists to enhance collaborative risk-benefit analysis, medication…

Steepest entropy ascent for two-state systems with slowly varying Hamiltonians

NASA Astrophysics Data System (ADS)

Militello, Benedetto

2018-05-01

The steepest entropy ascent approach is considered and applied to two-state systems. When the Hamiltonian of the system is time-dependent, the principle of maximum entropy production can still be exploited; arguments to support this fact are given. In the limit of slowly varying Hamiltonians, which allows for the adiabatic approximation for the unitary part of the dynamics, the system exhibits significant robustness to the thermalization process. Specific examples such as a spin in a rotating field and a generic two-state system undergoing an avoided crossing are considered.

Definitions of climate and climate change under varying external conditions

NASA Astrophysics Data System (ADS)

Werndl, C.

2014-06-01

Commonly, definitions of climate are endorsed where the external conditions are held constant. This paper argues that these definitions risk being empirically void because in reality the external conditions vary. As a consequence, analogous definitions for varying external conditions are explored with help of the recently developed theory of non-autonomous dynamical systems, and the similarities and differences between the cases of constant and varying external conditions are discussed. It is argued that there are analogous definitions for varying external conditions which are preferable to the definitions where the external conditions are held constant. In this context, a novel definition is proposed (namely, climate as the distribution over time under a regime of varying external conditions), which is argued to be promising.

Effects of Varying Team Sizes on Physical Activity Levels of College Students

ERIC Educational Resources Information Center

Gaudreault, Karen Lux; Cluphf, David; Russell, Jared; Lecheminant, James

2014-01-01

The purpose of this exploratory study was to examine physical activity levels among various team sizes for basketball and soccer in a C/UIPAP setting. Twenty-eight university physical education majors participated in the study. Participants engaged in three-on-three and five-on-five basketball and five-on-five and 11-on-11 soccer games. All games…

Music Activity Reports by Music Teachers with Varying Training in Orff Schulwerk

ERIC Educational Resources Information Center

Sogin, David W.; Wang, Cecilia Chu

2008-01-01

The purpose of this study was to examine music activities occurring in the music classroom of teachers who received different levels of training in Orff Schulwerk. The subjects (N = 49) were teachers participating in three training levels at a summer Orff Schulwerk certification program in a university in the USA. Teachers were asked to report the…

The Engagement in Musical Activities of Young Children with Varied Hearing Abilities

ERIC Educational Resources Information Center

Chen-Hafteck, Lily; Schraer-Joiner, Lyn

2011-01-01

This multiple case study examined the musical experiences of five hard-of-hearing/deaf children (hearing loss ranging from 35-95 dB) and four typical-hearing children, ages 3-4. Their responses to various musical activities were observed and analysed using flow indicators. It was found that both groups of children: (1) were capable of engaging in…

Clinical significance and developmental changes of auditory-language-related gamma activity

PubMed Central

Kojima, Katsuaki; Brown, Erik C.; Rothermel, Robert; Carlson, Alanna; Fuerst, Darren; Matsuzaki, Naoyuki; Shah, Aashit; Atkinson, Marie; Basha, Maysaa; Mittal, Sandeep; Sood, Sandeep; Asano, Eishi

2012-01-01

OBJECTIVE We determined the clinical impact and developmental changes of auditory-language-related augmentation of gamma activity at 50–120 Hz recorded on electrocorticography (ECoG). METHODS We analyzed data from 77 epileptic patients ranging 4 – 56 years in age. We determined the effects of seizure-onset zone, electrode location, and patient-age upon gamma-augmentation elicited by an auditory-naming task. RESULTS Gamma-augmentation was less frequently elicited within seizure-onset sites compared to other sites. Regardless of age, gamma-augmentation most often involved the 80–100 Hz frequency band. Gamma-augmentation initially involved bilateral superior-temporal regions, followed by left-side dominant involvement in the middle-temporal, medial-temporal, inferior-frontal, dorsolateral-premotor, and medial-frontal regions and concluded with bilateral inferior-Rolandic involvement. Compared to younger patients, those older than 10 years had a larger proportion of left dorsolateral-premotor and right inferior-frontal sites showing gamma-augmentation. The incidence of a post-operative language deficit requiring speech therapy was predicted by the number of resected sites with gamma-augmentation in the superior-temporal, inferior-frontal, dorsolateral-premotor, and inferior-Rolandic regions of the left hemisphere assumed to contain essential language function (r2=0.59; p=0.001; odds ratio=6.04 [95% confidence-interval: 2.26 to 16.15]). CONCLUSIONS Auditory-language-related gamma-augmentation can provide additional information useful to localize the primary language areas. SIGNIFICANCE These results derived from a large sample of patients support the utility of auditory-language-related gamma-augmentation in presurgical evaluation. PMID:23141882

The significance of denitrifying polyphosphate accumulating organisms in biological nutrient removal activated sludge systems.

PubMed

Hu, Z R; Wentzel, M C; Ekama, G A

2002-01-01

In this paper the advantages and disadvantages of denitrifying PAOs (polyphosphate accumulating organisms) in conventional BNRAS (biological nutrient removal activated sludge) and external nitrification BNRAS (ENBNRAS) systems are evaluated, with experimental data exhibiting a range of anoxic P uptake from low (<10%) to very high (>60%). The results indicate that the specific denitrification rate of the PAOs on internally stored PHB COD is about 1/5th of that of the "ordinary" heterotrophic organisms on SBCOD, and the PAOs contribute little (maximum 20%) to the denitrification in BNRAS systems even when the anoxic P uptake is high (60% of the total P uptake). Considering the unpredictable nature of anoxic P uptake and the reduction in BEPR it causes compared with aerobic P uptake BEPR, it is concluded that anoxic P uptake does not add a significant advantage to the BNR system.

Specimen loading list for the varying temperature experiment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qualls, A.L.; Sitterson, R.G.

1998-09-01

The varying temperature experiment HFIR-RB-13J has been assembled and inserted in the reactor. Approximately 5300 specimens were cleaned, inspected, matched, and loaded into four specimen holders. A listing of each specimen loaded into the steady temperature holder, its position in the capsule, and the identification of the corresponding specimen loaded into the varying temperature holder is presented in this report.

Formulating Spatially Varying Performance in the Statistical Fusion Framework

PubMed Central

Landman, Bennett A.

2012-01-01

To date, label fusion methods have primarily relied either on global (e.g. STAPLE, globally weighted vote) or voxelwise (e.g. locally weighted vote) performance models. Optimality of the statistical fusion framework hinges upon the validity of the stochastic model of how a rater errs (i.e., the labeling process model). Hitherto, approaches have tended to focus on the extremes of potential models. Herein, we propose an extension to the STAPLE approach to seamlessly account for spatially varying performance by extending the performance level parameters to account for a smooth, voxelwise performance level field that is unique to each rater. This approach, Spatial STAPLE, provides significant improvements over state-of-the-art label fusion algorithms in both simulated and empirical data sets. PMID:22438513

Activation of AMP-activated protein kinase in response to temperature elevation shows seasonal variation in the zebra mussel, Dreissena polymorpha.

PubMed

Jost, Jennifer A; Keshwani, Sarah S; Abou-Hanna, Jacob J

2015-04-01

Global climate change is affecting ectothermic species, and a variety of studies are needed on thermal tolerances, especially from cellular and physiological perspectives. This study utilized AMP-activated protein kinase (AMPK), a key regulator of cellular energy levels, to examine the effects of high water temperatures on zebra mussel (Dreissena polymorpha) physiology. During heating, AMPK activity increased as water temperature increased to a point, and maximum AMPK activity was detected at high, but sublethal, water temperatures. This pattern varied with season, suggesting that cellular mechanisms of seasonal thermal acclimatization affect basic metabolic processes during sublethal heat stress. There was a greater seasonal variation in the water temperature at which maximum AMPK activity was measured than in lethal water temperature. Furthermore, baseline AMPK activity varied significantly across seasons, most likely reflecting altered metabolic states during times of growth and reproduction. In addition, when summer-collected mussels were lab-acclimated to winter and spring water temperatures, patterns of heat stress mirrored those of field-collected animals. These data suggest that water temperature is the main driver of the seasonal variation in physiology. This study concluded that AMPK activity, which reflects changes in energy supply and demand during heat stress, can serve as a sensitive and early indicator of temperature stress in mussels. Copyright © 2014 Elsevier Inc. All rights reserved.

Inferring Time-Varying Network Topologies from Gene Expression Data

PubMed Central

2007-01-01

Most current methods for gene regulatory network identification lead to the inference of steady-state networks, that is, networks prevalent over all times, a hypothesis which has been challenged. There has been a need to infer and represent networks in a dynamic, that is, time-varying fashion, in order to account for different cellular states affecting the interactions amongst genes. In this work, we present an approach, regime-SSM, to understand gene regulatory networks within such a dynamic setting. The approach uses a clustering method based on these underlying dynamics, followed by system identification using a state-space model for each learnt cluster—to infer a network adjacency matrix. We finally indicate our results on the mouse embryonic kidney dataset as well as the T-cell activation-based expression dataset and demonstrate conformity with reported experimental evidence. PMID:18309363

Inferring time-varying network topologies from gene expression data.

PubMed

Rao, Arvind; Hero, Alfred O; States, David J; Engel, James Douglas

2007-01-01

Most current methods for gene regulatory network identification lead to the inference of steady-state networks, that is, networks prevalent over all times, a hypothesis which has been challenged. There has been a need to infer and represent networks in a dynamic, that is, time-varying fashion, in order to account for different cellular states affecting the interactions amongst genes. In this work, we present an approach, regime-SSM, to understand gene regulatory networks within such a dynamic setting. The approach uses a clustering method based on these underlying dynamics, followed by system identification using a state-space model for each learnt cluster--to infer a network adjacency matrix. We finally indicate our results on the mouse embryonic kidney dataset as well as the T-cell activation-based expression dataset and demonstrate conformity with reported experimental evidence.

Spaceflight and simulated microgravity cause a significant reduction of key gene expression in early T-cell activation

PubMed Central

Martinez, Emily M.; Yoshida, Miya C.; Candelario, Tara Lynne T.

2015-01-01

Healthy immune function depends on precise regulation of lymphocyte activation. During the National Aeronautics and Space Administration (NASA) Apollo and Shuttle eras, multiple spaceflight studies showed depressed lymphocyte activity under microgravity (μg) conditions. Scientists on the ground use two models of simulated μg (sμg): 1) the rotating wall vessel (RWV) and 2) the random positioning machine (RPM), to study the effects of altered gravity on cell function before advancing research to the true μg when spaceflight opportunities become available on the International Space Station (ISS). The objective of this study is to compare the effects of true μg and sμg on the expression of key early T-cell activation genes in mouse splenocytes from spaceflight and ground animals. For the first time, we compared all three conditions of microgravity spaceflight, RPM, and RWV during immune gene activation of Il2, Il2rα, Ifnγ, and Tagap; moreover, we confirm two new early T-cell activation genes, Iigp1 and Slamf1. Gene expression for all samples was analyzed using quantitative real-time PCR (qRT-PCR). Our results demonstrate significantly increased gene expression in activated ground samples with suppression of mouse immune function in spaceflight, RPM, and RWV samples. These findings indicate that sμg models provide an excellent test bed for scientists to develop baseline studies and augment true μg in spaceflight experiments. Ultimately, sμg and spaceflight studies in lymphocytes may provide insight into novel regulatory pathways, benefiting both future astronauts and those here on earth suffering from immune disorders. PMID:25568077

Spaceflight and simulated microgravity cause a significant reduction of key gene expression in early T-cell activation.

PubMed

Martinez, Emily M; Yoshida, Miya C; Candelario, Tara Lynne T; Hughes-Fulford, Millie

2015-03-15

Healthy immune function depends on precise regulation of lymphocyte activation. During the National Aeronautics and Space Administration (NASA) Apollo and Shuttle eras, multiple spaceflight studies showed depressed lymphocyte activity under microgravity (μg) conditions. Scientists on the ground use two models of simulated μg (sμg): 1) the rotating wall vessel (RWV) and 2) the random positioning machine (RPM), to study the effects of altered gravity on cell function before advancing research to the true μg when spaceflight opportunities become available on the International Space Station (ISS). The objective of this study is to compare the effects of true μg and sμg on the expression of key early T-cell activation genes in mouse splenocytes from spaceflight and ground animals. For the first time, we compared all three conditions of microgravity spaceflight, RPM, and RWV during immune gene activation of Il2, Il2rα, Ifnγ, and Tagap; moreover, we confirm two new early T-cell activation genes, Iigp1 and Slamf1. Gene expression for all samples was analyzed using quantitative real-time PCR (qRT-PCR). Our results demonstrate significantly increased gene expression in activated ground samples with suppression of mouse immune function in spaceflight, RPM, and RWV samples. These findings indicate that sμg models provide an excellent test bed for scientists to develop baseline studies and augment true μg in spaceflight experiments. Ultimately, sμg and spaceflight studies in lymphocytes may provide insight into novel regulatory pathways, benefiting both future astronauts and those here on earth suffering from immune disorders.

Knowledge diffusion in complex networks by considering time-varying information channels

NASA Astrophysics Data System (ADS)

Zhu, He; Ma, Jing

2018-03-01

In this article, based on a model of epidemic spreading, we explore the knowledge diffusion process with an innovative mechanism for complex networks by considering time-varying information channels. To cover the knowledge diffusion process in homogeneous and heterogeneous networks, two types of networks (the BA network and the ER network) are investigated. The mean-field theory is used to theoretically draw the knowledge diffusion threshold. Numerical simulation demonstrates that the knowledge diffusion threshold is almost linearly correlated with the mean of the activity rate. In addition, under the influence of the activity rate and distinct from the classic Susceptible-Infected-Susceptible (SIS) model, the density of knowers almost linearly grows with the spreading rate. Finally, in consideration of the ubiquitous mechanism of innovation, we further study the evolution of knowledge in our proposed model. The results suggest that compared with the effect of the spreading rate, the average knowledge version of the population is affected more by the innovation parameter and the mean of the activity rate. Furthermore, in the BA network, the average knowledge version of individuals with higher degree is always newer than those with lower degree.

Significant accomplishments, 2008

DOT National Transportation Integrated Search

2008-01-01

BTS continues to look for new ways to assess and : meet the varied needs of its customers. The Bureau is : developing strategies for responding to recognized : needs and identifying pressing issues within the : transportation community. For example, ...

Significant accomplishments, 2007

DOT National Transportation Integrated Search

2007-01-01

BTS continues to look for new ways to assess : and meet the varied needs of its customers. The : Bureau is developing strategies for responding : to recognized needs and identifying pressing : issues within the transportation community. For : example...

Associations between health-enhancing physical activity and country of birth among women.

PubMed

Södergren, Marita; Sundquist, Kristina; Johansson, Sven-Erik; Sundquist, Jan; Hagströmer, Maria

2010-09-01

The purpose of this study was to examine the association between total self-reported health-enhancing physical activity and country of birth among women living in Sweden. Women (age 18 to 65 years) born in Sweden, Finland, Chile, and Iraq were recruited for this cross-sectional study. Data were collected by means of a postal questionnaire including the International Physical Activity Questionnaire (IPAQ-long version). Self-reported physical activity data were converted to MET-minutes per week and analyzed as continuous or categorical scores. A total of 2649 women were included in the analyses. The association between physical activity and country of birth was explored using ordinal logistic regression assuming proportional odds. The total physical activity differed significantly between the countries of birth (P < .001). Women from Finland had significant higher odds and women from Iraq had significantly lower odds for reporting higher levels of physical activity, compared with Swedish-born women. The direction of the associations between self-reported total health-enhancing physical activity varied by country of birth, which underlines the need to examine physical activity in each minority group separately.

Do effects of common case-mix adjusters on patient experiences vary across patient groups?

PubMed

de Boer, Dolf; van der Hoek, Lucas; Rademakers, Jany; Delnoij, Diana; van den Berg, Michael

2017-11-22

Many survey studies in health care adjust for demographic characteristics such as age, gender, educational attainment and general health when performing statistical analyses. Whether the effects of these demographic characteristics are consistent between patient groups remains to be determined. This is important as the rationale for adjustment is often that demographic sub-groups differ in their so-called 'response tendency'. This rationale may be less convincing if the effects of response tendencies vary across patient groups. The present paper examines whether the impact of these characteristics on patients' global rating of care varies across patient groups. Secondary analyses using multi-level regression models were performed on a dataset including 32 different patient groups and 145,578 observations. For each demographic variable, the 95% expected range of case-mix coefficients across patient groups is presented. In addition, we report whether the variance of coefficients for demographic variables across patient groups is significant. Overall, men, elderly, lower educated people and people in good health tend to give higher global ratings. However, these effects varied significantly across patient groups and included the possibility of no effect or an opposite effect in some patient groups. The response tendency attributed to demographic characteristics - such as older respondents being milder, or higher educated respondents being more critical - is not general or universal. As such, the mechanism linking demographic characteristics to survey results on patient experiences with quality of care is more complicated than a general response tendency. It is possible that the response tendency interacts with patient group, but it is also possible that other mechanisms are at play.

Microwave fidelity studies by varying antenna coupling

NASA Astrophysics Data System (ADS)

Köber, B.; Kuhl, U.; Stöckmann, H.-J.; Gorin, T.; Savin, D. V.; Seligman, T. H.

2010-09-01

The fidelity decay in a microwave billiard is considered, where the coupling to an attached antenna is varied. The resulting quantity, coupling fidelity, is experimentally studied for three different terminators of the varied antenna: a hard-wall reflection, an open wall reflection, and a 50Ω load, corresponding to a totally open channel. The model description in terms of an effective Hamiltonian with a complex coupling constant is given. Quantitative agreement is found with the theory obtained from a modified VWZ approach [J. J. M. Verbaarschot , Phys. Rep. 129, 367 (1985)10.1016/0370-1573(85)90070-5].

Dynamic divisive normalization predicts time-varying value coding in decision-related circuits.

PubMed

Louie, Kenway; LoFaro, Thomas; Webb, Ryan; Glimcher, Paul W

2014-11-26

Normalization is a widespread neural computation, mediating divisive gain control in sensory processing and implementing a context-dependent value code in decision-related frontal and parietal cortices. Although decision-making is a dynamic process with complex temporal characteristics, most models of normalization are time-independent and little is known about the dynamic interaction of normalization and choice. Here, we show that a simple differential equation model of normalization explains the characteristic phasic-sustained pattern of cortical decision activity and predicts specific normalization dynamics: value coding during initial transients, time-varying value modulation, and delayed onset of contextual information. Empirically, we observe these predicted dynamics in saccade-related neurons in monkey lateral intraparietal cortex. Furthermore, such models naturally incorporate a time-weighted average of past activity, implementing an intrinsic reference-dependence in value coding. These results suggest that a single network mechanism can explain both transient and sustained decision activity, emphasizing the importance of a dynamic view of normalization in neural coding. Copyright © 2014 the authors 0270-6474/14/3416046-12$15.00/0.

Gene Expression Profiling in Response to Ultraviolet Radiation in Maize Genotypes with Varying Flavonoid Content1[w

PubMed Central

Casati, Paula; Walbot, Virginia

2003-01-01

Microarray hybridization was used to assess acclimation responses to four UV regimes by near isogenic maize (Zea mays) lines varying in flavonoid content. We found that 355 of the 2,500 cDNAs tested were regulated by UV radiation in at least one genotype. Among these, 232 transcripts are assigned putative functions, whereas 123 encode unknown proteins. UV-B increased expression of stress response and ribosomal protein genes, whereas photosynthesis-associated genes were down-regulated; lines lacking UV-absorbing pigments had more dramatic responses than did lines with these pigments, confirming the shielding role of these compounds. Sunlight filtered to remove UV-B or UV-B plus UV-A resulted in significant expression changes in many genes not previously associated with UV responses. Some pathways regulated by UV radiation are shared with defense, salt, and oxidative stresses; however, UV-B radiation can activate additional pathways not shared with other stresses. PMID:12913132

Protein phosphorylation differs significantly among ontogenetic phases in Malus seedlings

PubMed Central

2014-01-01

Background Although protein phosphorylation is an important post-translational modification affecting protein function and metabolism, dynamic changes in this process during ontogenesis remain unexplored in woody angiosperms. Methods Phosphorylated proteins from leaves of three apple seedlings at juvenile, adult vegetative and reproductive stages were extracted and subjected to alkaline phosphatase pre-treatment. After separating the proteins by two-dimensional gel electrophoresis and phosphoprotein-specific Pro-Q Diamond staining, differentially expressed phosphoproteins were identified by MALDI-TOF-TOF mass spectrometry. Results A total of 107 phosphorylated protein spots on nine gels (three ontogenetic phases × three seedlings) were identified by MALDI-TOF-TOF mass spectrometry. The 55 spots of ribulose-1, 5-bisphosphate carboxylase/oxygenase (Rubisco) large-chain fragments varied significantly in protein abundance and degree of phosphorylation among ontogenetic phases. Abundances of the 27 spots corresponding to Rubisco activase declined between juvenile and reproductive phases. More extensively, phosphorylated β-tubulin chain spots with lower isoelectric points were most abundant during juvenile and adult vegetative phases. Conclusions Protein phosphorylation varied significantly during vegetative phase change and floral transition in apple seedlings. Most of the observed changes were consistent among seedlings and between hybrid populations. PMID:24904238

Routine Activities and Victimization at School: The Significance of Gender

ERIC Educational Resources Information Center

Popp, Ann Marie; Peguero, Anthony A.

2011-01-01

Routine activities theory has not fully considered the role of gender in shaping victimization and yet, the research literature clearly demonstrates that gender is associated with an individual's risk of victimization. In addition to the pervasive effect of gender on victimization, gender shapes an individual's daily routines and thus may create a…

Knee Kinetics during Squats of Varying Loads and Depths in Recreationally Trained Females.

PubMed

Flores, Victoria; Becker, James; Burkhardt, Eric; Cotter, Joshua

2018-03-06

The back squat exercise is typically practiced with varying squat depths and barbell loads. However, depth has been inconsistently defined, resulting in unclear safety precautions when squatting with loads. Additionally, females exhibit anatomical and kinematic differences to males which may predispose them to knee joint injuries. The purpose of this study was to characterize peak knee extensor moments (pKEMs) at three commonly practiced squat depths of above parallel, parallel, and full depth, and with three loads of 0% (unloaded), 50%, and 85% depth-specific one repetition maximum (1RM) in recreationally active females. Nineteen females (age, 25.1 ± 5.8 years; body mass, 62.5 ± 10.2 kg; height, 1.6 ± 0.10 m; mean ± SD) performed squats of randomized depth and load. Inverse dynamics were used to obtain pKEMs from three-dimensional knee kinematics. Depth and load had significant interaction effects on pKEMs (p = 0.014). Significantly greater pKEMs were observed at full depth compared to parallel depth with 50% 1RM load (p = 0.001, d = 0.615), and 85% 1RM load (p = 0.010, d = 0.714). Greater pKEMs were also observed at full depth compared to above parallel depth with 50% 1RM load (p = 0.003, d = 0.504). Results indicate effect of load on female pKEMs do not follow a progressively increasing pattern with either increasing depth or load. Therefore, when high knee loading is a concern, individuals are must carefully consider both the depth of squat being performed and the relative load they are using.

The Moderating Effect of Psychological Characteristics upon the Visionary Leadership Behavior of Principals from Varying Levels of School Climate.

ERIC Educational Resources Information Center

Kenworthy, Sue

1994-01-01

Results from a study with 41 Hawaiian elementary school principals indicate that, although there is no significant difference in visionary leadership scores of principals from varying levels of school climate when covaried with psychological characteristics, there is a significant main effect for "capacity of status" on visionary…

Elliptical varied line-space (EVLS) gratings

NASA Astrophysics Data System (ADS)

Thomas, Roger J.

2004-10-01

Imaging spectroscopy at wavelengths below 2000 Å offers an especially powerful method for studying many extended high-temperature astronomical objects, like the Sun and its outer layers. But the technology to make such measurements is also especially challenging, because of the poor reflectance of all standard materials at these wavelengths, and because the observation must be made from above the absorbing effects of the Earth's atmosphere. To solve these problems, single-reflection stigmatic spectrographs for XUV wavelengths have bee flown on several space missions based on designs with toroidal uniform line-space (TULS) or spherical varied line-space (SVLS) gratings that operate at near normal-incidence. More recently, three solar EUV/UV instruments have been selected that use toroidal varied line-space (TVLS) gratings; these are SUMI and RAISE, both sounding rocket payloads, and NEXUS, a SMEX satellite-mission. The next logical extension to such designs is the use of elliptical surfaces for varied line-space (EVLS) rulings. In fact, EVLS designs are found to provide superior imaging even at very large spectrograph magnifications and beam-speeds, permitting extremely high-quality performance in remarkably compact instrument packages. In some cases, such designs may be optimized even further by using a hyperbolic surface for the feeding telescope. The optical characteristics of two solar EUV spectrometers based on these concepts are described: EUS and EUI, both being developed as possible instruments for ESA's Solar Orbiter mission by consortia led by RAL and by MSSL, respectively.

Active Control of Liner Impedance by Varying Perforate Orifice Geometry

NASA Technical Reports Server (NTRS)

Ahuji, K. K.; Gaeta, R. J., Jr.

2000-01-01

The present work explored the feasibility of controlling the acoustic impedance of a resonant type acoustic liner. This was accomplished by translating one perforate over another of the same porosity creating a totally new perforate that had an intermediate porosity. This type of adjustable perforate created a variable orifice perforate whose orifices were non-circular. The key objective of the present study was to quantify, the degree of attenuation control that can be achieved by applying such a concept to the buried septum in a two-degree-of-freedom (2DOF) acoustic liner. An additional objective was to examine the adequacy of the existing impedance models to explain the behavior of the unique orifice shapes that result from the proposed silding perforate concept. Different orifice shapes with equivalent area were also examined to determine if highly non-circular orifices had a significant impact on the impedance.

Modelling tourists arrival using time varying parameter

NASA Astrophysics Data System (ADS)

Suciptawati, P.; Sukarsa, K. G.; Kencana, Eka N.

2017-06-01

The importance of tourism and its related sectors to support economic development and poverty reduction in many countries increase researchers’ attentions to study and model tourists’ arrival. This work is aimed to demonstrate time varying parameter (TVP) technique to model the arrival of Korean’s tourists to Bali. The number of Korean tourists whom visiting Bali for period January 2010 to December 2015 were used to model the number of Korean’s tourists to Bali (KOR) as dependent variable. The predictors are the exchange rate of Won to IDR (WON), the inflation rate in Korea (INFKR), and the inflation rate in Indonesia (INFID). Observing tourists visit to Bali tend to fluctuate by their nationality, then the model was built by applying TVP and its parameters were approximated using Kalman Filter algorithm. The results showed all of predictor variables (WON, INFKR, INFID) significantly affect KOR. For in-sample and out-of-sample forecast with ARIMA’s forecasted values for the predictors, TVP model gave mean absolute percentage error (MAPE) as much as 11.24 percent and 12.86 percent, respectively.

Sun-induced changes of stratum corneum hydration vary with age and gender in a normal Chinese population.

PubMed

Liu, Zhili; Song, Shunpeng; Luo, Wenhai; Elias, Peter M; Man, Mao-Qiang

2012-02-01

Previous studies have demonstrated that sun-induced alteration of epidermal permeability barrier function varies with gender and age. In the present study, we assess the stratum corneum (SC) hydration in sun-exposed males and females. A total of 168 subjects (84 males and 84 females) aged 19-75 years were enrolled. A multifunctional skin physiology monitor was used to measure SC hydration. In comparison with non-sun exposure, sun exposure does not cause a significant change in SC hydration in either young males or young females, whereas in aged females, a significant reduction of SC hydration is seen on the forehead and the dorsal hand of sun-exposed subjects. SC hydration on the canthus of both aged males and aged females is significantly lower than that of young subjects. Additionally, SC hydration on the dorsal hand of aged females is also significantly lower as compared with young females. Sun-induced reduction of SC hydration is more evident on the dorsal hand of aged females than that of males (P<0.001). Moreover, the SC rehydration capacity is significantly lower in sun-exposed aged females than in age-matched males. These results demonstrated that sun-induced changes of the SC hydration property vary with age and gender. © 2011 John Wiley & Sons A/S.

Injection of thermal and suprathermal seed particles into coronal shocks of varying obliquity

NASA Astrophysics Data System (ADS)

Battarbee, M.; Vainio, R.; Laitinen, T.; Hietala, H.

2013-10-01

Context. Diffusive shock acceleration in the solar corona can accelerate solar energetic particles to very high energies. Acceleration efficiency is increased by entrapment through self-generated waves, which is highly dependent on the amount of accelerated particles. This, in turn, is determined by the efficiency of particle injection into the acceleration process. Aims: We present an analysis of the injection efficiency at coronal shocks of varying obliquity. We assessed injection through reflection and downstream scattering, including the effect of a cross-shock potential. Both quasi-thermal and suprathermal seed populations were analysed. We present results on the effect of cross-field diffusion downstream of the shock on the injection efficiency. Methods: Using analytical methods, we present applicable injection speed thresholds that were compared with both semi-analytical flux integration and Monte Carlo simulations, which do not resort to binary thresholds. Shock-normal angle θBn and shock-normal velocity Vs were varied to assess the injection efficiency with respect to these parameters. Results: We present evidence of a significant bias of thermal seed particle injection at small shock-normal angles. We show that downstream isotropisation methods affect the θBn-dependence of this result. We show a non-negligible effect caused by the cross-shock potential, and that the effect of downstream cross-field diffusion is highly dependent on boundary definitions. Conclusions: Our results show that for Monte Carlo simulations of coronal shock acceleration a full distribution function assessment with downstream isotropisation through scatterings is necessary to realistically model particle injection. Based on our results, seed particle injection at quasi-parallel coronal shocks can result in significant acceleration efficiency, especially when combined with varying field-line geometry. Appendices are available in electronic form at http://www.aanda.org

The H159A mutant of yeast enolase 1 has significant activity.

PubMed

Brewer, J M; Holland, M J; Lebioda, L

2000-10-05

The function of His159 in the enolase mechanism is disputed. Recently, Vinarov and Nowak (Biochemistry (1999) 38, 12138-12149) prepared the H159A mutant of yeast enolase 1 and expressed this in Escherichia coli. They reported minimal (ca. 0.01% of the native value) activity, though the protein appeared to be correctly folded, according to its CD spectrum, tryptophan fluorescence, and binding of metal ion and substrate. We prepared H159A enolase using a multicopy plasmid and expressed the enzyme in yeast. Our preparations of H159A enolase have 0.2-0.4% of the native activity under standard assay conditions and are further activated by Mg(2+) concentrations above 1 mM to 1-1.5% of the native activity. Native enolase 1 (and enolase 2) are inhibited by such Mg(2+) concentrations. It is possible that His159 is necessary for correct folding of the enzyme and that expression in E. coli leads to largely misfolded protein. Copyright 2000 Academic Press.

Time-varying surface electromyography topography as a prognostic tool for chronic low back pain rehabilitation.

PubMed

Hu, Yong; Kwok, Jerry Weilun; Tse, Jessica Yuk-Hang; Luk, Keith Dip-Kei

2014-06-01

responding and nonresponding groups. The relative area (RA) and relative width (RW) of RMSD at flexion and extension in the responding group were significantly lower than those in the nonresponding group (p<.05). The areas under the ROC curve of RA and RW of RMSD at flexion and extension were greater than 0.7 and were statistically significant. The quantitative time-varying analysis of sEMG topography showed significant difference between the healthy and LBP groups. The discrepancies in quantitative dynamic sEMG topography of LBP group from normal group, in terms of RA and RW of RMSD at flexion and extension, were able to identify those LBP subjects who would respond to a conservative rehabilitation program focused on functional restoration of lumbar muscle. Copyright © 2014 Elsevier Inc. All rights reserved.

Combining users' activity survey and simulators to evaluate human activity recognition systems.

PubMed

Azkune, Gorka; Almeida, Aitor; López-de-Ipiña, Diego; Chen, Liming

2015-04-08

Evaluating human activity recognition systems usually implies following expensive and time-consuming methodologies, where experiments with humans are run with the consequent ethical and legal issues. We propose a novel evaluation methodology to overcome the enumerated problems, which is based on surveys for users and a synthetic dataset generator tool. Surveys allow capturing how different users perform activities of daily living, while the synthetic dataset generator is used to create properly labelled activity datasets modelled with the information extracted from surveys. Important aspects, such as sensor noise, varying time lapses and user erratic behaviour, can also be simulated using the tool. The proposed methodology is shown to have very important advantages that allow researchers to carry out their work more efficiently. To evaluate the approach, a synthetic dataset generated following the proposed methodology is compared to a real dataset computing the similarity between sensor occurrence frequencies. It is concluded that the similarity between both datasets is more than significant.

Alkylphenol Xenoestrogens with Varying Carbon Chain Lengths Differentially and Potently Activate Signaling and Functional Responses in GH3/B6/F10 Somatomammotropes

PubMed Central

Kochukov, Mikhail Y.; Jeng, Yow-Jiun; Watson, Cheryl S.

2009-01-01

Background Alkylphenols varying in their side-chain lengths [ethyl-, propyl-, octyl-, and nonylphenol (EP, PP, OP, and NP, respectively)] and bisphenol A (BPA) represent a large group of structurally related xenoestrogens that have endocrine-disruptive effects. Their rapid nongenomic effects that depend on structure for cell signaling and resulting functions are unknown. Objectives We compared nongenomic estrogenic activities of alkylphenols with BPA and 17β-estradiol (E2) in membrane estrogen receptor-α–enriched GH3/B6/F10 pituitary tumor cells. These actions included calcium (Ca) signaling, prolactin (PRL) release, extracellular-regulated kinase (ERK) phosphorylation, and cell proliferation. Methods We imaged Ca using fura-2, measured PRL release via radioimmunoassay, detected ERK phosphorylation by fixed cell immunoassay, and estimated cell number using the crystal violet assay. Results All compounds caused increases in Ca oscillation frequency and intracellular Ca volume at 100 fM to 1 nM concentrations, although long-chain alkylphenols were most effective. All estrogens caused rapid PRL release at concentrations as low as 1 fM to 10 pM; the potency of EP, PP, and NP exceeded that of E2. All compounds at 1 nM produced similar increases in ERK phosphorylation, causing rapid peaks at 2.5–5 min, followed by inactivation and additional 60-min peaks (except for BPA). Dose–response patterns of ERK activation at 5 min were similar for E2, BPA, and PP, whereas EP caused larger effects. Only E2 and NP increased cell number. Some rapid estrogenic responses showed correlations with the hydrophobicity of estrogenic molecules; the more hydrophobic OP and NP were superior at Ca and cell proliferation responses, whereas the less hydrophobic EP and PP were better at ERK activations. Conclusions Alkylphenols are potent estrogens in evoking these nongenomic responses contributing to complex functions; their hydrophobicity can largely predict these behaviors. PMID

Sorption studies of nickel ions onto activated carbon

NASA Astrophysics Data System (ADS)

Joshi, Parth; Vyas, Meet; Patel, Chirag

2018-05-01

Activated porous carbons are made through pyrolysis and activation of carbonaceous natural as well as synthetic precursors. The use of low-cost activated carbon derived from azadirachta indica, an agricultural waste material, has been investigated as a replacement for the current expensive methods of removing nickel ions from wastewater. The temperature variation study showed that the nickel ions adsorption is endothermic and spontaneous with increased randomness at the solid solution interface. Significant effect on adsorption was observed on varying the pH of the nickel ion solutions. Therefore, this study revealed that azadirachta indica can serve as a good source of activated carbon with multiple and simultaneous metal ions removing potentials and may serve as a better replacement for commercial activated carbons in applications that warrant their use.

Towards a Unified Understanding of Lithium Action in Basic Biology and its Significance for Applied Biology.

PubMed

Jakobsson, Eric; Argüello-Miranda, Orlando; Chiu, See-Wing; Fazal, Zeeshan; Kruczek, James; Nunez-Corrales, Santiago; Pandit, Sagar; Pritchet, Laura

2017-12-01

Lithium has literally been everywhere forever, since it is one of the three elements created in the Big Bang. Lithium concentration in rocks, soil, and fresh water is highly variable from place to place, and has varied widely in specific regions over evolutionary and geologic time. The biological effects of lithium are many and varied. Based on experiments in which animals are deprived of lithium, lithium is an essential nutrient. At the other extreme, at lithium ingestion sufficient to raise blood concentration significantly over 1 mM/, lithium is acutely toxic. There is no consensus regarding optimum levels of lithium intake for populations or individuals-with the single exception that lithium is a generally accepted first-line therapy for bipolar disorder, and specific dosage guidelines for sufferers of that condition are generally agreed on. Epidemiological evidence correlating various markers of social dysfunction and disease vs. lithium level in drinking water suggest benefits of moderately elevated lithium compared to average levels of lithium intake. In contrast to other biologically significant ions, lithium is unusual in not having its concentration in fluids of multicellular animals closely regulated. For hydrogen ions, sodium ions, potassium ions, calcium ions, chloride ions, and magnesium ions, blood and extracellular fluid concentrations are closely and necessarily regulated by systems of highly selective channels, and primary and secondary active transporters. Lithium, while having strong biological activity, is tolerated over body fluid concentrations ranging over many orders of magnitude. The lack of biological regulation of lithium appears due to lack of lithium-specific binding sites and selectivity filters. Rather lithium exerts its myriad physiological and biochemical effects by competing for macromolecular sites that are relatively specific for other cations, most especially for sodium and magnesium. This review will consider what is known

Biorhythms in the activity of children during free play.

PubMed

Wade, M G; Ellis, M J; Bohrer, R E

1973-07-01

The interaction between the arousal to action of environmental stimuli and recovery from that activity was presumed to generate biorhythms in the activity level of children. The level of environmental stimuli was manipulated by varying the play-group size and the apparatus, and higher environmental complexity was expected to produce more pronounced rhythms. The heart rates of 16 subjects playing in monad, dyad, and tetrad group sizes, in two playroom configurations, were monitored and spectral analysis used to locate significant biorhythms. There was a tendency toward 40-min (slow frequency) and 15-min (fast frequency) biorhythms. The group size manipulation produced the strongest biorhythmic behavior in the dyadic groups. Apparatus differences were not significant but the configuration containing a minimum quantity of play apparatus produced more variable activity than the configuration containing a large amount of play apparatus.

Genetic polymorphisms in varied environments.

PubMed

Powell, J R

1971-12-03

Thirteen experimenital populationis of Drosophila willistoni were maintained in cages, in some of which the environments were relatively constant and in others varied. After 45 weeks, the populations were assayed by gel electrophoresis for polymorphisms at 22 protein loci. The average heterozygosity per individual and the average unmber of alleles per locus were higher in populations maintained in heterogeneous environments than in populations in more constant enviroments.

Varied Practice in Laparoscopy Training: Beneficial Learning Stimulation or Cognitive Overload?

PubMed

Spruit, Edward N; Kleijweg, Luca; Band, Guido P H; Hamming, Jaap F

2016-01-01

Determining the optimal design for surgical skills training is an ongoing research endeavor. In education literature, varied practice is listed as a positive intervention to improve acquisition of knowledge and motor skills. In the current study we tested the effectiveness of a varied practice intervention during laparoscopy training. Twenty-four trainees (control group) without prior experience received a 3 weeks laparoscopic skills training utilizing four basic and one advanced training task. Twenty-eight trainees (experimental group) received the same training with a random training task schedule, more frequent task switching and inverted viewing conditions on the four basic training tasks, but not the advanced task. Results showed inferior performance of the experimental group on the four basic laparoscopy tasks during training, at the end of training and at a 2 months retention session. We assume the inverted viewing conditions have led to the deterioration of learning in the experimental group because no significant differences were found between groups on the only task that had not been practiced under inverted viewing conditions; the advanced laparoscopic task. Potential moderating effects of inter-task similarity, task complexity, and trainee characteristics are discussed.

Search for Varying Constants of Nature from Astronomical Observation of Molecules

NASA Astrophysics Data System (ADS)

Ubachs, Wim

2018-02-01

The status of searches for possible variation in the constants of nature from astronomical observation of molecules is reviewed, focusing on the dimensionless constant representing the proton-electron mass ratio μ =mp/me. The optical detection of H2 and CO molecules with large ground-based telescopes (as the ESO-VLT and the Keck telescopes), as well as the detection of H2 with the Cosmic Origins Spectrograph aboard the Hubble Space Telescope is discussed in the context of varying constants, and in connection to different theoretical scenarios. Radio astronomy provides an alternative search strategy bearing the advantage that molecules as NH3 (ammonia) and CH3OH (methanol) can be used, which are much more sensitive to a varying μ than diatomic molecules. Current constraints are |Δ μ /μ | < 5 × 10^{-6} for redshift z=2.0-4.2, corresponding to look-back times of 10-12.5 Gyrs, and |Δ μ / μ | < 1.5 × 10^{-7} for z=0.88, corresponding to half the age of the Universe (both at 3σ statistical significance). Existing bottlenecks and prospects for future improvement with novel instrumentation are discussed.

Varied Practice in Laparoscopy Training: Beneficial Learning Stimulation or Cognitive Overload?

PubMed Central

Spruit, Edward N.; Kleijweg, Luca; Band, Guido P. H.; Hamming, Jaap F.

2016-01-01

Determining the optimal design for surgical skills training is an ongoing research endeavor. In education literature, varied practice is listed as a positive intervention to improve acquisition of knowledge and motor skills. In the current study we tested the effectiveness of a varied practice intervention during laparoscopy training. Twenty-four trainees (control group) without prior experience received a 3 weeks laparoscopic skills training utilizing four basic and one advanced training task. Twenty-eight trainees (experimental group) received the same training with a random training task schedule, more frequent task switching and inverted viewing conditions on the four basic training tasks, but not the advanced task. Results showed inferior performance of the experimental group on the four basic laparoscopy tasks during training, at the end of training and at a 2 months retention session. We assume the inverted viewing conditions have led to the deterioration of learning in the experimental group because no significant differences were found between groups on the only task that had not been practiced under inverted viewing conditions; the advanced laparoscopic task. Potential moderating effects of inter-task similarity, task complexity, and trainee characteristics are discussed. PMID:27242599

Impulsive effect on global exponential stability of BAM fuzzy cellular neural networks with time-varying delays

NASA Astrophysics Data System (ADS)

Li, Kelin

2010-02-01

In this article, a class of impulsive bidirectional associative memory (BAM) fuzzy cellular neural networks (FCNNs) with time-varying delays is formulated and investigated. By employing delay differential inequality and M-matrix theory, some sufficient conditions ensuring the existence, uniqueness and global exponential stability of equilibrium point for impulsive BAM FCNNs with time-varying delays are obtained. In particular, a precise estimate of the exponential convergence rate is also provided, which depends on system parameters and impulsive perturbation intention. It is believed that these results are significant and useful for the design and applications of BAM FCNNs. An example is given to show the effectiveness of the results obtained here.

Multimodal Pilot Behavior in Multi-Axis Tracking Tasks with Time-Varying Motion Cueing Gains

NASA Technical Reports Server (NTRS)

Zaal, P. M. T; Pool, D. M.

2014-01-01

In a large number of motion-base simulators, adaptive motion filters are utilized to maximize the use of the available motion envelope of the motion system. However, not much is known about how the time-varying characteristics of such adaptive filters affect pilots when performing manual aircraft control. This paper presents the results of a study investigating the effects of time-varying motion filter gains on pilot control behavior and performance. An experiment was performed in a motion-base simulator where participants performed a simultaneous roll and pitch tracking task, while the roll and/or pitch motion filter gains changed over time. Results indicate that performance increases over time with increasing motion gains. This increase is a result of a time-varying adaptation of pilots' equalization dynamics, characterized by increased visual and motion response gains and decreased visual lead time constants. Opposite trends are found for decreasing motion filter gains. Even though the trends in both controlled axes are found to be largely the same, effects are less significant in roll. In addition, results indicate minor cross-coupling effects between pitch and roll, where a cueing variation in one axis affects the behavior adopted in the other axis.

Effect of varying the pressurisation rate during noninvasive pressure support ventilation.

PubMed

Prinianakis, G; Delmastro, M; Carlucci, A; Ceriana, P; Nava, S

2004-02-01

The aim of the study was to assess the effects of varying the pressurisation rate during noninvasive pressure support ventilation on patients' breathing pattern, inspiratory effort, arterial blood gases, tolerance to ventilation and amount of air leakage. A total of 15 chronic obstructive pulmonary disease patients recovering from an acute episode of hypercapnic acute respiratory failure were studied during four randomised trials with different levels of pressurisation rate. No significant changes were observed in breathing pattern and arterial blood gases between the different runs. The pressure time product of the diaphragm, an estimate of its metabolic consumption, was significantly lower with all pressurisation rates than with spontaneous breathing, but was significantly lowest with the fastest rate. However, air leak, assessed by the ratio between expired and inspired tidal volumes, increased and the patients' tolerance of ventilation, measured using a standardised scale, was significantly poorer with the fastest pressurisation rate. In chronic obstructive pulmonary disease patients recovering from an episode of acute hypercapnic respiratory failure and ventilated with noninvasive pressure support ventilation, different pressurisation rates resulted in different reductions in the pressure time product of the diaphragm; this reduction was greater with the fastest rate, but was accompanied by significant air leaks and poor tolerance.

Modeling polar cap F-region patches using time varying convection

NASA Technical Reports Server (NTRS)

Sojka, J. J.; Bowline, M. D.; Schunk, R. W.; Decker, D. T.; Valladares, C. E.; Sheehan, R.; Anderson, D. N.; Heelis, R. A.

1993-01-01

Creation of polar cap F-region patches are simulated for the first time using two independent physical models of the high latitude ionosphere. The patch formation is achieved by temporally varying the magnetospheric electric field (ionospheric convection) input to the models. The imposed convection variations are comparable to changes in the convection that result from changes in the B(y) IMF component for southward IMF. Solar maximum-winter simulations show that simple changes in the convection pattern lead to significant changes in the polar cap plasma structuring. Specifically, in winter, as enhanced dayside plasma convects into the polar cap to form the classic tongue-of-ionization the convection changes produce density structures that are indistinguishable from the observed patches.

The Design of 3D-Printed Lattice-Reinforced Thickness-Varying Shell Molds for Castings.

PubMed

Shangguan, Haolong; Kang, Jinwu; Yi, Jihao; Zhang, Xiaochuan; Wang, Xiang; Wang, Haibin; Huang, Tao

2018-03-30

3D printing technologies have been used gradually for the fabrication of sand molds and cores for castings, even though these molds and cores are dense structures. In this paper, a generation method for lattice-reinforced thickness-varying shell molds is proposed and presented. The first step is the discretization of the STL (Stereo Lithography) model of a casting into finite difference meshes. After this, a shell is formed by surrounding the casting with varying thickness, which is roughly proportional to the surface temperature distribution of the casting that is acquired by virtually cooling it in the environment. A regular lattice is subsequently constructed to support the shell. The outside surface of the shell and lattice in the cubic mesh format is then converted to STL format to serve as the external surface of the new shell mold. The internal surface of the new mold is the casting's surface with the normals of all of the triangles in STL format reversed. Experimental verification was performed on an Al alloy wheel hub casting. Its lattice-reinforced thickness-varying shell mold was generated by the proposed method and fabricated by the binder jetting 3D printing. The poured wheel hub casting was sound and of good surface smoothness. The cooling rate of the wheel hub casting was greatly increased due to the shell mold structure. This lattice-reinforced thickness-varying shell mold generation method is of great significance for mold design for castings to achieve cooling control.

Do radioactive half-lives vary with the Earth-to-Sun distance?

PubMed

Hardy, J C; Goodwin, J R; Iacob, V E

2012-09-01

Recently, Jenkins, Fischbach and collaborators have claimed evidence that radionuclide half-lives vary systematically over a ±0.1% range as a function of the oscillating distance between the Earth and the Sun, based on multi-year activity measurements. We have avoided the time-dependent instabilities to which such measurements are susceptible by directly measuring the half-life of (198)Au (t(1/2)=2.695 d) on seven occasions spread out in time to cover the complete range of Earth-Sun distances. We observe no systematic oscillations in half-life and can set an upper limit on their amplitude of ±0.02%. Copyright © 2012 Elsevier Ltd. All rights reserved.

Correlates and perceived outcomes of four types of employee development activity.

PubMed

Birdi, K; Allan, C; Warr, P

1997-12-01

Participation in 4 different types of development activity was studied in a sample of manufacturing employees (N = 1,798). It was found that similar sets of variables were linked to greater participation in 3 activities: required training courses in work time, work-based development activity in work time, and career planning activity in work time or an individual's own time. Three kinds of reported benefits were studied, and the occurrence of these benefits was found to vary between different types of development activity. Overall job satisfaction and organizational commitment were significantly associated with prior participation in required training courses and work-based development activity. However, voluntary learning in one's own time was completely unrelated to these work attitudes.

Single versus triple daily activation of the distractor: no significant effects of frequency of distraction on bone regenerate quantity and architecture.

PubMed

Djasim, Urville Mardijanto; Wolvius, Eppo Bonne; Van Neck, Johan Wilhelm; Van Wamel, Annemieke; Weinans, Harrie; Van Der Wal, Karel George Hendrik

2008-04-01

To study the effect of two different frequencies of distraction on the quantity and architecture of bone regenerate using micro-computed tomography, and to determine whether radiographic and ultrasonographic bone-fill scores provide reliable predictive value for the amount of new bone in the distraction area. Twenty-six skeletally mature rabbits underwent three full days of latency, after which midface distraction was started. Low-frequency group (n=12): a distraction rate of 0.9 mm/d achieved by one daily activation for 11 days to create a 10mm distraction gap. High-frequency group (n=12): idem, but three daily activations were used instead of one. Control group (n=2) underwent no distraction. After 21 days of consolidation, bone-fill in the distraction area was assessed by means of ultrasonography and radiography. Micro-computed tomography was used to quantify new bone formation and bone architecture. Relative bone volume (BV/TV) showed a tendency towards a difference (P=0.09) between the low and high-frequency groups. No significant differences were found for bone architecture. No significant correlation between BV/TV values and bone-fill scores was found. An increase in rhythm from one to three activations daily does not create significantly more bone. Bone-fill score values provided no reliable predictive value for the amount of new bone formation.

Varying potential silicon carbide gas sensor

NASA Technical Reports Server (NTRS)

Shields, Virgil B. (Inventor); Ryan, Margaret A. (Inventor); Williams, Roger M. (Inventor)

1997-01-01

A hydrocarbon gas detection device operates by dissociating or electro-chemically oxidizing hydrocarbons adsorbed to a silicon carbide detection layer. Dissociation or oxidation are driven by a varying potential applied to the detection layer. Different hydrocarbon species undergo reaction at different applied potentials so that the device is able to discriminate among various hydrocarbon species. The device can operate at temperatures between 100.degree. C. and at least 650.degree. C., allowing hydrocarbon detection in hot exhaust gases. The dissociation reaction is detected either as a change in a capacitor or, preferably, as a change of current flow through an FET which incorporates the silicon carbide detection layers. The silicon carbide detection layer can be augmented with a pad of catalytic material which provides a signal without an applied potential. Comparisons between the catalytically produced signal and the varying potential produced signal may further help identify the hydrocarbon present.

A study of bone marrow and subcutaneous fatty acid composition in subjects of varying bone mineral density.

PubMed

Griffith, James F; Yeung, David K W; Ahuja, Anil T; Choy, Carol W Y; Mei, Wong Yin; Lam, Sherlock S L; Lam, T P; Chen, Zhen-Yu; Leung, Ping C

2009-06-01

Osteoporosis is associated with an increase in marrow fat. Fats, particularly polyunsaturated fats, either in co-cultures or diet, have been shown to significantly influence bone remodeling. Whether the increase in marrow fat seen in osteoporosis is also associated with a change in fatty acid composition is not known. This study was undertaken to investigate the fatty acid composition in subjects of varying bone mineral density (BMD). Samples of marrow fat and subcutaneous fat from 126 subjects (98 females, 34 males, mean age 69.7+/-10.5 years) undergoing orthopedic surgery were analyzed for fatty acid composition by gas chromatography. These results were correlated with BMD assessed by DXA. A total of 22 fatty acids were identified in marrow and subcutaneous fat. Significant differences in fatty acid composition existed between marrow and subcutaneous fat as well as between marrow fat samples obtained from the proximal femur and proximal tibia. Other than cis-7-hexadecenoic acid [C16:1 (n=9)] and docosanoic acid [C22:0], no difference in marrow fatty acid composition was evident between subject groups of varying BMD (normal, low bone mass, and osteoporosis). In conclusion, there exists a wide range of individual fatty acids in marrow fat. Marrow fatty acid composition differs from that of subcutaneous fat and varies between predominantly erythropoetic and fatty marrow sites. Other than cis-7-hexadecenoic acid [C16:1 (n=9)] and docosanoic acid [C22:0], no difference in marrow fatty acid composition was evident between subjects of varying BMD.

Clever strategists: Australian Magpies vary mobbing strategies, not intensity, relative to different species of predator

PubMed Central

Koboroff, A; Kaplan, G

2013-01-01

Anti-predator behaviour of magpies was investigated, using five species of model predators, at times of raising offspring. We predicted differences in mobbing strategies for each predator presented and also that raising juveniles would affect intensity of the mobbing event. Fourteen permanent resident family groups were tested using 5 different types of predator (avian and reptilian) known to be of varying degrees of risk to magpies and common in their habitat. In all, 210 trials were conducted (across three different stages of juvenile development). We found that the stage of juvenile development did not alter mobbing behaviour significantly, but predator type did. Aerial strategies (such as swooping) were elicited by taxidermic models of raptors, whereas a taxidermic model of a monitor lizard was approached on the ground and a model snake was rarely approached. Swooping patterns also changed according to which of the three raptors was presented. Our results show that, in contrast to findings in other species, magpies vary mobbing strategy depending on the predator rather than varying mobbing intensity. PMID:23638394

Clever strategists: Australian Magpies vary mobbing strategies, not intensity, relative to different species of predator.

PubMed

Koboroff, A; Kaplan, G; Rogers, Lj

2013-01-01

Anti-predator behaviour of magpies was investigated, using five species of model predators, at times of raising offspring. We predicted differences in mobbing strategies for each predator presented and also that raising juveniles would affect intensity of the mobbing event. Fourteen permanent resident family groups were tested using 5 different types of predator (avian and reptilian) known to be of varying degrees of risk to magpies and common in their habitat. In all, 210 trials were conducted (across three different stages of juvenile development). We found that the stage of juvenile development did not alter mobbing behaviour significantly, but predator type did. Aerial strategies (such as swooping) were elicited by taxidermic models of raptors, whereas a taxidermic model of a monitor lizard was approached on the ground and a model snake was rarely approached. Swooping patterns also changed according to which of the three raptors was presented. Our results show that, in contrast to findings in other species, magpies vary mobbing strategy depending on the predator rather than varying mobbing intensity.

Mechanism and active variety of allelochemicals

USGS Publications Warehouse

Peng, S.-L.; Wen, J.; Guo, Q.-F.

2004-01-01

This article summarizes allelochemicals' active variety, its potential causes and function mechanisms. Allelochemicals' activity varies with temperature, photoperiod, water and soils during natural processes, with its initial concentration, compound structure and mixed degree during functional processes, with plant accessions, tissues and maturity within-species, and with research techniques and operation processes. The prospective developmental aspects of allelopathy studies in the future are discussed. Future research should focus on: (1) to identify and purify allelochemicals more effectively, especially for agriculture, (2) the functions of allelopathy at the molecular structure level, (3) using allelopathy to explain plant species interactions, (4) allelopathy as a driving force of succession, and (5) the significance of allelopathy in the evolutionary processes.

The significance of gut sucrase activity for osmoregulation in the pea aphid, Acyrthosiphon pisum.

PubMed

Karley, A J; Ashford, D A; Minto, L M; Pritchard, J; Douglas, A E

2005-12-01

The osmotic pressure of the body fluids of aphids is lower than in their diet of plant phloem sap. It is hypothesised that aphids reduce the osmotic pressure of ingested food by sucrase-mediated hydrolysis of dietary sucrose to glucose and fructose, and the polymerisation of glucose into oligosaccharides of low osmotic pressure per hexose unit. To test this hypothesis, the impact of the alpha-glucosidase inhibitor acarbose on the sugar relations and osmoregulation of aphids was explored. Acarbose inhibited sucrase activity in gut homogenates and the production of monosaccharides and oligosaccharides in the honeydew of live aphids. Acarbose caused an increase in the haemolymph osmotic pressure for aphids reared on a diet (containing 0.75 M sucrose) hyperosmotic to the haemolymph and not on the isoosmotic diet containing 0.2 M sucrose. It did not affect aphid feeding rate over 2 days, except at high concentrations on 0.75 M sucrose diet, and this may have been a secondary consequence of osmotic dysfunction. Acarbose-treated aphids died prematurely. With 5 microM dietary acarbose, mean survivorship on 0.2 M sucrose diet was 4.2 days, not significantly different from starved aphids, indicating that, although these aphids fed, they were deprived of utilisable carbon; and on 0.75 M sucrose diet, mean survivorship was just 2.8 days, probably as a consequence of osmotic failure. It is concluded that the aphid gut sucrase activity is essential for osmoregulation of aphids ingesting food hyperosmotic to their body fluids.

The effects of residual platelets in plasma on plasminogen activator inhibitor-1 and plasminogen activator inhibitor-1-related assays.

PubMed

Pieters, Marlien; Barnard, Sunelle A; Loots, Du Toit; Rijken, Dingeman C

2017-01-01

Due to controversial evidence in the literature pertaining to the activity of plasminogen activator inhibitor-1 in platelets, we examined the effects of residual platelets present in plasma (a potential pre-analytical variable) on various plasminogen activator inhibitor-1 and plasminogen activator inhibitor-1-related assays. Blood samples were collected from 151 individuals and centrifuged at 352 and 1500 g to obtain plasma with varying numbers of platelet. In a follow-up study, blood samples were collected from an additional 23 individuals, from whom platelet-poor (2000 g), platelet-containing (352 g) and platelet-rich plasma (200 g) were prepared and analysed as fresh-frozen and after five defrost-refreeze cycles (to determine the contribution of in vitro platelet degradation). Plasminogen activator inhibitor-1 activity, plasminogen activator inhibitor-1 antigen, tissue plasminogen activator/plasminogen activator inhibitor-1 complex, plasma clot lysis time, β-thromboglobulin and plasma platelet count were analysed. Platelet α-granule release (plasma β-thromboglobulin) showed a significant association with plasminogen activator inhibitor-1 antigen levels but weak associations with plasminogen activator inhibitor-1 activity and a functional marker of fibrinolysis, clot lysis time. Upon dividing the study population into quartiles based on β-thromboglobulin levels, plasminogen activator inhibitor-1 antigen increased significantly across the quartiles while plasminogen activator inhibitor-1 activity and clot lysis time tended to increase in the 4th quartile only. In the follow-up study, plasma plasminogen activator inhibitor-1 antigen was also significantly influenced by platelet count in a concentration-dependent manner. Plasma plasminogen activator inhibitor-1 antigen levels increased further after complete platelet degradation. Residual platelets in plasma significantly influence plasma plasminogen activator inhibitor-1 antigen levels mainly through release of

Consumer acceptance of model soup system with varying levels of herbs and salt.

PubMed

Wang, Chao; Lee, Youngsoo; Lee, Soo-Yeun

2014-10-01

Although herbs have been reported as one of the most common saltiness enhancers, few studies have focused on the effect of herbs on reducing added sodium as well as the impact of herbs on consumers' overall liking of foods. Therefore, the objectives of this study were to determine the effect of varying levels of herbs on reducing added sodium and consumers' overall liking of soups and identify the impact of salt levels on consumers' overall liking of soups. Overall liking of freshly prepared and retorted canned soups with varying levels of herbs was evaluated before and after adding salt by consumers ad libitum until the saltiness of the soup was just about right for them. The results of the study demonstrated that when the perceived herb flavor increased, the amount of salt consumers added to fresh soups decreased (P ≤ 0.006); however, consumers' overall liking decreased (P ≤ 0.013) as well for the highest level of herb tested in the study. Although overall liking of all canned soups was not significantly decreased by herbs, the amount of salt consumers added was also not significantly decreased when herbs were used. Overall liking of all soups significantly increased after more salt was added (P ≤ 0.001), which indicates that salt level was a dominant factor in affecting consumers' overall liking of soups with varying levels of herbs. These findings imply the role of herbs in decreasing salt intake, and the adequate amount of herbs to be added in soup systems. It is challenging for the food industry to reduce sodium in foods without fully understanding the impact of sodium reduction on sensory properties of foods. Herbs are recommended to use in reducing sodium; however, little has been reported regarding the effect of herbs on sodium reduction and how herbs influence consumers’ acceptance of foods. This study provides findings that herbs may aid in decreasing the amount of salt consumers need to add for freshly prepared soups. It was also found that high

EMG activity across gait and incline: The impact of muscular activity on human morphology

PubMed Central

Wall-Scheffler, Cara M.; Chumanov, Elizabeth; Steudel-Numbers, Karen; Heiderscheit, Bryan

2010-01-01

The study of human evolution depends upon a fair assessment of the ability of hominin individuals to gain access to necessary resources. We expect that the morphology of extant and extinct populations represents a successful locomotory system that allowed individuals to move across the environment gaining access to food, water and mates while still maintaining excess energy to allocate to reproduction. Our assessment of locomotor morphology must then incorporate tests of fitness within realistic environments—environments that themselves vary in terrain and whose negotiation requires a variety of gait and speeds. This study assesses muscular activity (measured as the integrated signal from surface electromyography) of seven thigh and hip muscle groups during walking and running across a wide range of speeds and inclines, in order to systematically assess the role that morphology can play in minimizing muscular activity and thus energy expenditure. Our data suggest that humans are better adapted to walking than running at any slope, as evidenced by small confidence intervals and even trends across speed and incline. We find that while increasing task intensity unsurprisingly increases muscular activity in the lower limb, individuals with longer limbs show significantly reduced activity during both walking and running, especially in the hip adductors, gluteus maximus and hamstring muscles. People with a broader pelvis show significantly reduced activity while walking in the hip adductor and hamstring muscles. PMID:20623603

Time-Varying Value of Energy Efficiency in Michigan

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mims, Natalie; Eckman, Tom; Schwartz, Lisa C.

Quantifying the time-varying value of energy efficiency is necessary to properly account for all of its benefits and costs and to identify and implement efficiency resources that contribute to a low-cost, reliable electric system. Historically, most quantification of the benefits of efficiency has focused largely on the economic value of annual energy reduction. Due to the lack of statistically representative metered end-use load shape data in Michigan (i.e., the hourly or seasonal timing of electricity savings), the ability to confidently characterize the time-varying value of energy efficiency savings in the state, especially for weather-sensitive measures such as central air conditioning,more » is limited. Still, electric utilities in Michigan can take advantage of opportunities to incorporate the time-varying value of efficiency into their planning. For example, end-use load research and hourly valuation of efficiency savings can be used for a variety of electricity planning functions, including load forecasting, demand-side management and evaluation, capacity planning, long-term resource planning, renewable energy integration, assessing potential grid modernization investments, establishing rates and pricing, and customer service (KEMA 2012). In addition, accurately calculating the time-varying value of efficiency may help energy efficiency program administrators prioritize existing offerings, set incentive or rebate levels that reflect the full value of efficiency, and design new programs.« less

Tension in Skinned Frog Muscle Fibers in Solutions of Varying Ionic Strength and Neutral Salt Composition

PubMed Central

Gordon, A. M.; Godt, R. E.; Donaldson, S. K. B.; Harris, C. E.

1973-01-01

The maximal calcium-activated isometric tension produced by a skinned frog single muscle fiber falls off as the ionic strength of the solution bathing this fiber is elevated declining to zero near 0.5 M as the ionic strength is varied using KCl. When other neutral salts are used, the tension always declines at high ionic strength, but there is some difference between the various neutral salts used. The anions and cations can be ordered in terms of their ability to inhibit the maximal calcium-activated tension. The order of increasing inhibition of tension (decreasing tension) at high ionic strength for anions is propionate- ≃ SO4 -- < Cl- < Br-. The order of increasing inhibition of calcium-activated tension for cations is K+ ≃ Na+ ≃ TMA+ < TEA+ < TPrA+ < TBuA+. The decline of maximal calcium-activated isometric tension with elevated salt concentration (ionic strength) can quantitatively explain the decline of isometric tetanic tension of a frog muscle fiber bathed in a hypertonic solution if one assumes that the internal ionic strength of a muscle fiber in normal Ringer's solution is 0.14–0.17 M. There is an increase in the base-line tension of a skinned muscle fiber bathed in a relaxing solution (no added calcium and 3 mM EGTA) of low ionic strength. This tension, which has no correlate in the intact fiber in hypotonic solutions, appears to be a noncalcium-activated tension and correlates more with a declining ionic strength than with small changes in [MgATP], [Mg], pH buffer, or [EGTA]. It is dependent upon the specific neutral salts used with cations being ordered in increasing inhibition of this noncalcium-activated tension (decreasing tension) as TPrA+ < TMA+ < K+ ≃ Na+. Measurements of potentials inside these skinned muscle fibers bathed in relaxing solutions produced occasional small positive values (<6 mV) which were not significantly different from zero. PMID:4543066

Time-varying higher order spectra

NASA Astrophysics Data System (ADS)

Boashash, Boualem; O'Shea, Peter

1991-12-01

A general solution for the problem of time-frequency signal representation of nonlinear FM signals is provided, based on a generalization of the Wigner-Ville distribution. The Wigner- Ville distribution (WVD) is a second order time-frequency representation. That is, it is able to give ideal energy concentration for quadratic phase signals and its ensemble average is a second order time-varying spectrum. The same holds for Cohen's class of time-frequency distributions, which are smoothed versions of the WVD. The WVD may be extended so as to achieve ideal energy concentration for higher order phase laws, and such that the expectation is a time-varying higher order spectrum. The usefulness of these generalized Wigner-Ville distributions (GWVD) is twofold. Firstly, because they achieve ideal energy concentration for polynomial phase signals, they may be used for optimal instantaneous frequency estimation. Second, they are useful for discriminating between nonstationary processes of differing higher order moments. In the same way that the WVD is generalized, we generalize Cohen's class of TFDs by defining a class of generalized time-frequency distributions (GTFDs) obtained by a two dimensional smoothing of the GWVD. Another results derived from this approach is a method based on higher order spectra which allows the separation of cross-terms and auto- terms in the WVD.

Predictors of BMI Vary along the BMI Range of German Adults - Results of the German National Nutrition Survey II.

PubMed

Moon, Kilson; Krems, Carolin; Heuer, Thorsten; Roth, Alexander; Hoffmann, Ingrid

2017-01-01

The objective of the study was to identify predictors of BMI in German adults by considering the BMI distribution and to determine whether the association between BMI and its predictors varies along the BMI distribution. The sample included 9,214 adults aged 18-80 years from the German National Nutrition Survey II (NVS II). Quantile regression analyses were conducted to examine the association between BMI and the following predictors: age, sports activities, socio-economic status (SES), healthy eating index-NVS II (HEI-NVS II), dietary knowledge, sleeping duration and energy intake as well as status of smoking, partner relationship and self-reported health. Age, SES, self-reported health status, sports activities and energy intake were the strongest predictors of BMI. The important outcome of this study is that the association between BMI and its predictors varies along the BMI distribution. Especially, energy intake, health status and SES were marginally associated with BMI in normal-weight subjects; this relationships became stronger in the range of overweight, and were strongest in the range of obesity. Predictors of BMI and the strength of these associations vary across the BMI distribution in German adults. Consequently, to identify predictors of BMI, the entire BMI distribution should be considered. © 2017 The Author(s) Published by S. Karger GmbH, Freiburg.

Stereoscopic depth perception varies with hues

NASA Astrophysics Data System (ADS)

Chen, Zaiqing; Shi, Junsheng; Tai, Yonghang; Yun, Lijun

2012-09-01

The contribution of color information to stereopsis is controversial, and whether the stereoscopic depth perception varies with chromaticity is ambiguous. This study examined the changes in depth perception caused by hue variations. Based on the fact that a greater disparity range indicates more efficient stereoscopic perception, the effect of hue variations on depth perception was evaluated through the disparity range with random-dot stereogram stimuli. The disparity range was obtained by constant-stimulus method for eight chromaticity points sampled from the CIE 1931 chromaticity diagram. Eight sample points include four main color hues: red, yellow, green, and blue at two levels of chroma. The results show that the disparity range for the yellow hue is greater than the red hue, the latter being greater than the blue hue and the disparity range for green hue is smallest. We conclude that the perceived depth is not the same for different hues for a given size of disparity. We suggest that the stereoscopic depth perception can vary with chromaticity.

Bioactive compounds and antioxidant activities of some cereal milling by-products.

PubMed

Smuda, Sayed Saad; Mohsen, Sobhy Mohamed; Olsen, Karsten; Aly, Mohamed Hassan

2018-03-01

The present study was performed to evaluate the phytochemicals profiles of some cereal milling by-products such as wheat (bran, germ and shorts), rice (bran, germ and husk) and corn (bran, germ and germ meal) to assess their potentiality as bioactive compounds sources. Distilled water, ethanol, methanol, and acetone separately were used as solvents for the extraction of phytochemicals compounds. The antioxidant activity (AOA), total phenolics content (TPC), and total flavonoids content (TFC) of the extracts were investigated using various in vitro assays. The results showed that tannins content was ranged from 113.4 to 389.5 (mg/100 g sample).The study revealed that TPC and TFC of cereal by-products extracts were significantly different for various solvents. TPC content varied from 366.1 to 1924.9 mg/100 g and TFC content varied from 139.3 to 681.6 mg/100 g. High carotenoids content was observed for corn germ meal and minimum for wheat bran. Distilled water, ethanol and methanol extracts showed significantly different antioxidant activity. Significant variations were observed with regard to AOA of different cereal by-products by using various solvents. The ethanol and methanol were observed to be the best solvents to extract phenolic compounds and antioxidant activity, while acetone extract showed less efficiency. Also, the cereal milling by-products were rich in bioactive compounds and could be used as a value added products.

The Influence of Varying Cost Formats on Preferences

PubMed Central

Jiang, Charles Changchuan; Fraenkel, Liana

2016-01-01

Background Numerous studies have found that cost strongly influences patients’ decision-making. The objective of this study was to explore the impact of varying cost formats on patients’ preferences. Methods Mechanical Turk workers completed a choice based conjoint (CBC) analysis survey. The CBC survey was designed to examine stated preferences for second line agents used to treat diabetes using five attributes: route of administration, efficacy, risk of low blood sugar, frequency of checking blood sugar levels and cost. We developed seven versions of the CBC survey which were identical except for the cost attribute. We described cost in terms of: Affordability, Monthly co-pay, Dollar Sign Rating, How Expensive or How Cheap compared to other medications, Monthly Co-pay, Working Hours Equivalent (per month) and Percent of Monthly Income. The resulting part-worth utilities were used to calculate the relative importance of cost and to estimate treatment preferences for a sulfonylurea, exenatide and insulin. Results The relative impact of cost varied significantly across the seven formats. Cost had the greatest influence on participants’ decisions when framed in terms of Affordability [mean (SD) relative importance = 37.3 (0.9)] and the lowest influence when framed in terms of How Cheap (compared to other drugs) [mean (SD) relative importance= 12.1 (0.9)]. A sulfonylurea was strongly preferred across four of the seven formats. Preference for insulin, the most effective, albeit riskiest option, was low across all cost formats. Conclusions The format used to describe cost influences how this attribute impacts patients’ preferences. Individuals are most cost-sensitive when cost is framed in terms of affordability and least cost-sensitive when cost is described in terms of how cheap the medication is compared to others. PMID:27856826

A compensation controller based on a regional pole-assignment method for AMD control systems with a time-varying delay

NASA Astrophysics Data System (ADS)

Li, Zuohua; Chen, Chaojun; Teng, Jun; Wang, Ying

2018-04-01

Active mass damper/driver (AMD) control system has been proposed as an effective tool for high-rise buildings to resist strong dynamic loads. However, such disadvantage as time-varying delay in AMD control systems impedes their application in practices. Time-varying delay, which has an effect on the performance and stability of single-degree-of-freedom (SDOF) and multi-degree-of-freedom (MDOF) systems, is considered in the paper. In addition, a new time-delay compensation controller based on regional pole-assignment method is presented. To verify its effectiveness, the proposed method is applied to a numerical example of a ten-storey frame and an experiment of a single span four-storey steel frame. Both numerical and experimental results demonstrate that the proposed method can enhance the performances of an AMD control system with time-varying delays.

Respiratory parameters at varied altitudes in intermittent mining work.

PubMed

Bacaloni, Alessandro; Zamora Saà, Margarita Cecilia; Sinibaldi, Federica; Steffanina, Alessia; Insogna, Susanna

2018-01-07

Workers in the mining industry in altitude are subjected to several risk factors, e.g., airborne silica and low barometric pressure. The aim of this study has been to assess the risks for this work category, evaluating single risk factors as airborne silica, altitude and work shift, and relating them with cardiovascular and ventilatory parameters. Healthy miners employed in a mining company, Chile, working at varied altitudes, and subjected to unusual work shifts, were evaluated. Cardiovascular and respiratory parameters were investigated. Exposure to airborne silica was evaluated and compared to currently binding exposure limits. At varied altitudes and work shifts, alterations emerged in haemoglobin, ventilation and respiratory parameters, related to employment duration, due to compensatory mechanisms for hypoxia. Haemoglobin increased with altitude, saturation fell down under 90% in the highest mines. The multiple linear regression analysis showed a direct relationship, in the higher mine, between years of exposure to altitude and increased forced vital capacity percent (FVC%), and forced expiratory volume in 1 s (FEV1). An inverse relationship emerged between forced vital capacity (FVC) and years of exposure to airborne silica. In the workplace Mina Subterrànea (MT-3600), statistically significant inverse relationship emerged between the Tiffeneau index and body weight. The working conditions in the mining industry in altitude appeared to be potentially pathogenic; further investigations should be realized integrating risk assessment protocols even in consideration of their undeniable unconventionality. Int J Occup Med Environ Health 2018;31(2):129-138. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

Effects of Varying Gravity Levels on fNIRS Headgear Performance and Signal Recovery

NASA Technical Reports Server (NTRS)

Mackey, Jeffrey R.; Harrivel, Angela R.; Adamovsky, Grigory; Lewandowski, Beth E.; Gotti, Daniel J.; Tin, Padetha; Floyd, Bertram M.

2013-01-01

This paper reviews the effects of varying gravitational levels on functional Near-Infrared Spectroscopy (fNIRS) headgear. The fNIRS systems quantify neural activations in the cortex by measuring hemoglobin concentration changes via optical intensity. Such activation measurement allows for the detection of cognitive state, which can be important for emotional stability, human performance and vigilance optimization, and the detection of hazardous operator state. The technique depends on coupling between the fNIRS probe and users skin. Such coupling may be highly susceptible to motion if probe-containing headgear designs are not adequately tested. The lack of reliable and self-applicable headgear robust to the influence of motion artifact currently inhibits its operational use in aerospace environments. Both NASAs Aviation Safety and Human Research Programs are interested in this technology as a method of monitoring cognitive state of pilots and crew.

The hippocampal response to psychosocial stress varies with salivary uric acid level

PubMed Central

Goodman, Adam M.; Wheelock, Muriah D.; Harnett, Nathaniel G.; Mrug, Sylvie; Granger, Douglas A.; Knight, David C.

2016-01-01

Uric acid is a naturally occurring, endogenous compound that impacts mental health. In particular, uric acid levels are associated with emotion-related psychopathology (e.g., anxiety and depression). Therefore, understanding uric acid’s impact on the brain would provide valuable new knowledge regarding neural mechanisms that mediate the relationship between uric acid and mental health. Brain regions including the prefrontal cortex, amygdala, and hippocampus underlie stress reactivity and emotion regulation. Thus, uric acid may impact emotion by modifying the function of these brain regions. The present study used functional magnetic resonance imaging (fMRI) during a psychosocial stress task to investigate the relationship between baseline uric acid levels (in saliva) and brain function. Results demonstrate that activity within the bilateral hippocampal complex varied with uric acid concentrations. Specifically, activity within the hippocampus and surrounding cortex increased as a function of uric acid level. The current findings suggest that uric acid levels modulate stress-related hippocampal activity. Given that the hippocampus has been implicated in emotion regulation during psychosocial stress, the present findings offer a potential mechanism by which uric acid impacts mental health. PMID:27725214

Barnacle geese achieve significant energetic savings by changing posture.

PubMed

Tickle, Peter G; Nudds, Robert L; Codd, Jonathan R

2012-01-01

Here we report the resting metabolic rate in barnacle geese (Branta leucopsis) and provide evidence for the significant energetic effect of posture. Under laboratory conditions flow-through respirometry together with synchronous recording of behaviour enabled a calculation of how metabolic rate varies with posture. Our principal finding is that standing bipedally incurs a 25% increase in metabolic rate compared to birds sitting on the ground. In addition to the expected decrease in energy consumption of hindlimb postural muscles when sitting, we hypothesise that a change in breathing mechanics represents one potential mechanism for at least part of the observed difference in energetic cost. Due to the significant effect of posture, future studies of resting metabolic rates need to take into account and/or report differences in posture.

Biorhythms in the activity of children during free play1

PubMed Central

Wade, M. G.; Ellis, M. J.; Bohrer, R. E.

1973-01-01

The interaction between the arousal to action of environmental stimuli and recovery from that activity was presumed to generate biorhythms in the activity level of children. The level of environmental stimuli was manipulated by varying the play-group size and the apparatus, and higher environmental complexity was expected to produce more pronounced rhythms. The heart rates of 16 subjects playing in monad, dyad, and tetrad group sizes, in two playroom configurations, were monitored and spectral analysis used to locate significant biorhythms. There was a tendency toward 40-min (slow frequency) and 15-min (fast frequency) biorhythms. The group size manipulation produced the strongest biorhythmic behavior in the dyadic groups. Apparatus differences were not significant but the configuration containing a minimum quantity of play apparatus produced more variable activity than the configuration containing a large amount of play apparatus. PMID:4714575

Multiple autophosphorylations significantly enhance the endoribonuclease activity of human inositol requiring enzyme 1α

PubMed Central

2014-01-01

Background Endoplasmic reticulum stress, caused by the presence of misfolded proteins, activates the stress sensor inositol-requiring enzyme 1α (IRE1α). The resulting increase in IRE1α RNase activity causes sequence-specific cleavage of X-box binding protein 1 (XBP1) mRNA, resulting in upregulation of the unfolded protein response and cellular adaptation to stress. The precise mechanism of human IRE1α activation is currently unclear. The role of IRE1α kinase activity is disputed, as results from the generation of various kinase-inactivating mutations in either yeast or human cells are discordant. Kinase activity can also be made redundant by small molecules which bind the ATP binding site. We set out to uncover a role for IRE1α kinase activity using wild-type cytosolic protein constructs. Results We show that concentration-dependent oligomerisation is sufficient to cause IRE1α cytosolic domain RNase activity in vitro. We demonstrate a role for the kinase activity by showing that autophosphorylation enhances RNase activity. Inclusion of the IRE1α linker domain in protein constructs allows hyperphosphorylation and further enhancement of RNase activity, highlighting the importance of kinase activity. We show that IRE1α phosphorylation status correlates with an increased propensity to form oligomeric complexes and that forced dimerisation causes great enhancement in RNase activity. In addition we demonstrate that even when IRE1α is forced to dimerise, by a GST-tag, phospho-enhancement of activity is still observed. Conclusions Taken together these experiments support the hypothesis that phosphorylation is important in modulating IRE1α RNase activity which is achieved by increasing the propensity of IRE1α to dimerise. This work supports the development of IRE1α kinase inhibitors for use in the treatment of secretory cancers. PMID:24524643

Teaching Significant Figures Using a Learning Cycle.

ERIC Educational Resources Information Center

Guymon, E. Park; And Others

1986-01-01

Describes an instructional strategy based on the learning cycle for teaching the use of significant figures. Provides explanations of teaching activities for each phase of the learning cycle (exploration, invention, application). Compares this approach to teaching significant figures with the traditional textbook approach. (TW)

The Design of 3D-Printed Lattice-Reinforced Thickness-Varying Shell Molds for Castings

PubMed Central

Shangguan, Haolong; Kang, Jinwu; Yi, Jihao; Zhang, Xiaochuan; Wang, Xiang; Wang, Haibin; Huang, Tao

2018-01-01

3D printing technologies have been used gradually for the fabrication of sand molds and cores for castings, even though these molds and cores are dense structures. In this paper, a generation method for lattice-reinforced thickness-varying shell molds is proposed and presented. The first step is the discretization of the STL (Stereo Lithography) model of a casting into finite difference meshes. After this, a shell is formed by surrounding the casting with varying thickness, which is roughly proportional to the surface temperature distribution of the casting that is acquired by virtually cooling it in the environment. A regular lattice is subsequently constructed to support the shell. The outside surface of the shell and lattice in the cubic mesh format is then converted to STL format to serve as the external surface of the new shell mold. The internal surface of the new mold is the casting’s surface with the normals of all of the triangles in STL format reversed. Experimental verification was performed on an Al alloy wheel hub casting. Its lattice-reinforced thickness-varying shell mold was generated by the proposed method and fabricated by the binder jetting 3D printing. The poured wheel hub casting was sound and of good surface smoothness. The cooling rate of the wheel hub casting was greatly increased due to the shell mold structure. This lattice-reinforced thickness-varying shell mold generation method is of great significance for mold design for castings to achieve cooling control. PMID:29601543

The Varied Uses of Readability Measurement.

ERIC Educational Resources Information Center

Fry, Edward

Readability formulas have varied uses. In education they are used to match children's reading ability to the difficulty level of material, select stories and books for classroom use and for individual students' particular needs, select textbooks and other reading materials, aid educational research, and check reading materials of newly literate…

Cell segmentation in time-lapse fluorescence microscopy with temporally varying sub-cellular fusion protein patterns.

PubMed

Bunyak, Filiz; Palaniappan, Kannappan; Chagin, Vadim; Cardoso, M

2009-01-01

Fluorescently tagged proteins such as GFP-PCNA produce rich dynamically varying textural patterns of foci distributed in the nucleus. This enables the behavioral study of sub-cellular structures during different phases of the cell cycle. The varying punctuate patterns of fluorescence, drastic changes in SNR, shape and position during mitosis and abundance of touching cells, however, require more sophisticated algorithms for reliable automatic cell segmentation and lineage analysis. Since the cell nuclei are non-uniform in appearance, a distribution-based modeling of foreground classes is essential. The recently proposed graph partitioning active contours (GPAC) algorithm supports region descriptors and flexible distance metrics. We extend GPAC for fluorescence-based cell segmentation using regional density functions and dramatically improve its efficiency for segmentation from O(N(4)) to O(N(2)), for an image with N(2) pixels, making it practical and scalable for high throughput microscopy imaging studies.

Significantly enhanced photocatalytic activity of visible light responsive AgBr/Bi2Sn2O7 heterostructured composites

NASA Astrophysics Data System (ADS)

Hu, Chaohao; Zhuang, Jing; Zhong, Liansheng; Zhong, Yan; Wang, Dianhui; Zhou, Huaiying

2017-12-01

Heterostructured AgBr/Bi2Sn2O7 photocatalysts were synthesized successfully via the ultrasonic-assisted chemical precipitation method. XRD, FT-IR, FE-SEM, TEM, XPS, UV-vis-DRS and PL spectroscopy were used to characterize the phase structure, morphology, chemical composition, oxidation state, and optical properties of AgBr/Bi2Sn2O7 heterojunction. The photocatalytic activity of as-prepared catalysts was evaluated by the degradation of RhB under visible light irradiation. The obtained AgBr/Bi2Sn2O7 composite with the 1:1 molar ratio exhibited significantly enhanced photocatalytic performance. Further first-principles calculations indicated that the hybridization interaction between Ag and O atoms at AgBr/Bi2Sn2O7 interface is expected to be beneficial for enhancing the charge transfer and improving the photocatalytic activity of heterostructured composites.

Significant activities of extracellular enzymes from a brown tide in the coastal waters of Qinhuangdao, China.

PubMed

Ou, Linjian; Liu, Xiaohong; Li, Jingjing; Qin, Xianling; Cui, Lei; Lu, Songhui

2018-04-01

Brown tides of Aureococcus anophagefferens have occurred annually in the coastal waters of Qinhuangdao since 2009. High levels of dissolved organic matter (DOM) are always measured during bloom periods. Study focusing on the effect of DOM on the occurrences of brown tides in this area is scare by far. To analyze the efficiency of DOM hydrolysis by different groups of microorganisms and the possible influence of DOM on the formation of brown tides, extracellular enzymes such as α, β-glucosidases (α, β-GLUs), leucine aminopeptidase (LAP) and alkaline phosphatase (AP) as well as other environmental parameters were analyzed during a pre-bloom period of A. anophagefferens in June 2014. Dissolved organic nitrogen (DON) and phosphorus (DOP) contributed more than half of the total dissolved nutrient pools. Approximately 60-70% of the enzyme activities were associated with phytoplankton of size >5 μm. The hydrolysis rates of LAP were approximately 5 to 20 fold higher than those of AP and α, β-GLUs. The ratios of β-GLU activities: LAP activities indicated the hydrolysis potential related to proteins rather than polysaccharides. The differences in turnover time among the enzymes suggested that DOP was firstly hydrolyzed and recycled in the water in the early minutes, followed by the hydrolysis of DON and dissolved organic carbon (DOC)(in hours). Results suggest that the hydrolysis of DOM, in particular DOP, might significantly contribute to the occurrences of brown tides in the coastal waters of Qinhuangdao, China. Copyright © 2018 Elsevier B.V. All rights reserved.

Micro-Viscometer for Measuring Shear-Varying Blood Viscosity over a Wide-Ranging Shear Rate.

PubMed

Kim, Byung Jun; Lee, Seung Yeob; Jee, Solkeun; Atajanov, Arslan; Yang, Sung

2017-06-20

In this study, a micro-viscometer is developed for measuring shear-varying blood viscosity over a wide-ranging shear rate. The micro-viscometer consists of 10 microfluidic channel arrays, each of which has a different micro-channel width. The proposed design enables the retrieval of 10 different shear rates from a single flow rate, thereby enabling the measurement of shear-varying blood viscosity with a fixed flow rate condition. For this purpose, an optimal design that guarantees accurate viscosity measurement is selected from a parametric study. The functionality of the micro-viscometer is verified by both numerical and experimental studies. The proposed micro-viscometer shows 6.8% (numerical) and 5.3% (experimental) in relative error when compared to the result from a standard rotational viscometer. Moreover, a reliability test is performed by repeated measurement (N = 7), and the result shows 2.69 ± 2.19% for the mean relative error. Accurate viscosity measurements are performed on blood samples with variations in the hematocrit (35%, 45%, and 55%), which significantly influences blood viscosity. Since the blood viscosity correlated with various physical parameters of the blood, the micro-viscometer is anticipated to be a significant advancement for realization of blood on a chip.

Micro-Viscometer for Measuring Shear-Varying Blood Viscosity over a Wide-Ranging Shear Rate

PubMed Central

Kim, Byung Jun; Lee, Seung Yeob; Jee, Solkeun; Atajanov, Arslan; Yang, Sung

2017-01-01

In this study, a micro-viscometer is developed for measuring shear-varying blood viscosity over a wide-ranging shear rate. The micro-viscometer consists of 10 microfluidic channel arrays, each of which has a different micro-channel width. The proposed design enables the retrieval of 10 different shear rates from a single flow rate, thereby enabling the measurement of shear-varying blood viscosity with a fixed flow rate condition. For this purpose, an optimal design that guarantees accurate viscosity measurement is selected from a parametric study. The functionality of the micro-viscometer is verified by both numerical and experimental studies. The proposed micro-viscometer shows 6.8% (numerical) and 5.3% (experimental) in relative error when compared to the result from a standard rotational viscometer. Moreover, a reliability test is performed by repeated measurement (N = 7), and the result shows 2.69 ± 2.19% for the mean relative error. Accurate viscosity measurements are performed on blood samples with variations in the hematocrit (35%, 45%, and 55%), which significantly influences blood viscosity. Since the blood viscosity correlated with various physical parameters of the blood, the micro-viscometer is anticipated to be a significant advancement for realization of blood on a chip. PMID:28632151

Latent myostatin has significant activity and this activity is controlled more efficiently by WFIKKN1 than by WFIKKN2

PubMed Central

Szláma, György; Trexler, Mária; Patthy, László

2013-01-01

Myostatin, a negative regulator of skeletal muscle growth, is produced from myostatin precursor by multiple steps of proteolytic processing. After cleavage by a furin-type protease, the propeptide and growth factor domains remain associated, forming a noncovalent complex, the latent myostatin complex. Mature myostatin is liberated from latent myostatin by bone morphogenetic protein 1/tolloid proteases. Here, we show that, in reporter assays, latent myostatin preparations have significant myostatin activity, as the noncovalent complex dissociates at an appreciable rate, and both mature and semilatent myostatin (a complex in which the dimeric growth factor domain interacts with only one molecule of myostatin propeptide) bind to myostatin receptor. The interaction of myostatin receptor with semilatent myostatin is efficiently blocked by WAP, Kazal, immunoglobulin, Kunitz and NTR domain-containing protein 1 or growth and differentiation factor-associated serum protein 2 (WFIKKN1), a large extracellular multidomain protein that binds both mature myostatin and myostatin propeptide [Kondás et al. (2008) J Biol Chem 283, 23677–23684]. Interestingly, the paralogous protein WAP, Kazal, immunoglobulin, Kunitz and NTR domain-containing protein 2 or growth and differentiation factor-associated serum protein 1 (WFIKKN2) was less efficient than WFIKKN1 as an antagonist of the interactions of myostatin receptor with semilatent myostatin. Our studies have shown that this difference is attributable to the fact that only WFIKKN1 has affinity for the propeptide domain, and this interaction increases its potency in suppressing the receptor-binding activity of semilatent myostatin. As the interaction of WFIKKN1 with various forms of myostatin permits tighter control of myostatin activity until myostatin is liberated from latent myostatin by bone morphogenetic protein 1/tolloid proteases, WFIKKN1 may have greater potential as an antimyostatic agent than WFIKKN2

Context-dependent decisions among options varying in a single dimension.

PubMed

Morgan, Kate V; Hurly, T Andrew; Bateson, Melissa; Asher, Lucy; Healy, Susan D

2012-02-01

Contrary to theories of rational choice, adding alternatives to a choice set can change the choices made by both humans and animals. This is usually done by adding an inferior decoy to a choice set of two favoured options that are characterized on two distinct dimensions. We presented wild, free-living rufous hummingbirds (Selasphorus rufus) with choices between two or three options that varied in a single dimension only. The options varied in concentration, in volume or in corolla length. When the options varied in concentration, the addition of a medium option to a choice set of a low and a high concentration caused birds to increase their preference for the high option. However, they decreased their preference for the high concentration option when a low option was added to a choice set of high and medium concentrations. When the options varied only in volume, the addition of a high volume option to a choice set of low and medium options decreased the birds' preference for the medium option. We saw no effects of adding a third option when the options varied in corolla length alone. Hummingbirds, then, make context-dependent decisions even when the options vary in only a single dimension although which effect occurs seems to depend on the dimension being manipulated. None of the current theories alone adequately explain these results. Copyright © 2011 Elsevier B.V. All rights reserved.

Expression and Significance of Neuroligins in Myenteric Cells of Cajal in Hirschsprung's Disease

PubMed Central

Wang, Jian; Mou, Yaru; Zhang, Qiangye; Zhang, Fan; Yang, Hongchao; Zhang, Wentong; Li, Aiwu

2013-01-01

Purpose The aim of this study was to investigate the expression and significance of neuroligins in myenteric cells of Cajal (ICC-MY) in Hirschsprung’s disease (HSCR). Methods Longitudinal muscle with adherent myenteric plexus (LMMP) from surgical excision waste colon of HSCR children were prepared by peeling off the mucous layer, sub-mucosal layer and circular muscle. Neuroligins, c-Kit (c-Kit-immunoreactivity representing ICC) and their relationship were assessed by double labeling immunofluorescence staining. ICC-MY were dissociated and cultured from LMMP by enzymolysis method, and were purified and analyzed using a combination of magnetic-activated cell sorting (MACS) and flow cytometry (FCM). Western-blot analysis was applied to compare and evaluate the expression levels of neuroligins in ICC-MY which were dissociated from different segments of HSCR (ganglionic colonic segment, transitional colonic segment and aganglionic colonic segment). Results Neuroligins and c-Kit were expressed on the same cells (ICC-MY); ICC-MY were dissociated, cultured and purified. For HSCR, neuroligins were expressed significantly in ICC-MY from ganglionic colonic segments, moderately in those from transitional colonic segments and down-regulated significantly in those from aganglionic colonic segments. Conclusions Neuroligins were expressed in ICC-MY of human beings, and the expression varies from different segments of HSCR. This abnormal expression might play an important role in the pathogenesis of this disease through affecting the synaptic function of ICC-MY. PMID:23840625

Augmented brain function by coordinated reset stimulation with slowly varying sequences.

PubMed

Zeitler, Magteld; Tass, Peter A

2015-01-01

Several brain disorders are characterized by abnormally strong neuronal synchrony. Coordinated Reset (CR) stimulation was developed to selectively counteract abnormal neuronal synchrony by desynchronization. For this, phase resetting stimuli are delivered to different subpopulations in a timely coordinated way. In neural networks with spike timing-dependent plasticity CR stimulation may eventually lead to an anti-kindling, i.e., an unlearning of abnormal synaptic connectivity and abnormal synchrony. The spatiotemporal sequence by which all stimulation sites are stimulated exactly once is called the stimulation site sequence, or briefly sequence. So far, in simulations, pre-clinical and clinical applications CR was applied either with fixed sequences or rapidly varying sequences (RVS). In this computational study we show that appropriate repetition of the sequence with occasional random switching to the next sequence may significantly improve the anti-kindling effect of CR. To this end, a sequence is applied many times before randomly switching to the next sequence. This new method is called SVS CR stimulation, i.e., CR with slowly varying sequences. In a neuronal network with strong short-range excitatory and weak long-range inhibitory dynamic couplings SVS CR stimulation turns out to be superior to CR stimulation with fixed sequences or RVS.

Augmented brain function by coordinated reset stimulation with slowly varying sequences

PubMed Central

Zeitler, Magteld; Tass, Peter A.

2015-01-01

Several brain disorders are characterized by abnormally strong neuronal synchrony. Coordinated Reset (CR) stimulation was developed to selectively counteract abnormal neuronal synchrony by desynchronization. For this, phase resetting stimuli are delivered to different subpopulations in a timely coordinated way. In neural networks with spike timing-dependent plasticity CR stimulation may eventually lead to an anti-kindling, i.e., an unlearning of abnormal synaptic connectivity and abnormal synchrony. The spatiotemporal sequence by which all stimulation sites are stimulated exactly once is called the stimulation site sequence, or briefly sequence. So far, in simulations, pre-clinical and clinical applications CR was applied either with fixed sequences or rapidly varying sequences (RVS). In this computational study we show that appropriate repetition of the sequence with occasional random switching to the next sequence may significantly improve the anti-kindling effect of CR. To this end, a sequence is applied many times before randomly switching to the next sequence. This new method is called SVS CR stimulation, i.e., CR with slowly varying sequences. In a neuronal network with strong short-range excitatory and weak long-range inhibitory dynamic couplings SVS CR stimulation turns out to be superior to CR stimulation with fixed sequences or RVS. PMID:25873867

High-Tech Versus High-Touch: Components of Hospital Costs Vary Widely.

PubMed

Song, Paula H; Reiter, Kristin L; Yi Xu, Wendy

The recent release by the Centers for Medicare & Medicaid Services of hospital charge and payment data to the public has renewed a national dialogue on hospital costs and prices. However, to better understand the driving force of hospital pricing and to develop strategies for controlling expenditures, it is important to understand the underlying costs of providing hospital services. We use Medicare Provider and Analysis Review inpatient claims data and Medicare cost report data for fiscal years 2008 and 2012 to examine variations in the contribution of "high-tech" resources (i.e., technology/medical device-intensive resources) versus "high-touch" resources (i.e., labor-intensive resources) to the total costs of providing two common services, as well as assess how these costs have changed over time. We found that high-tech inputs accounted for a greater proportion of the total costs of surgical service, whereas medical service costs were primarily attributable to high-touch inputs. Although the total costs of services did not change significantly over time, the distribution of high-tech, high-touch, and other costs for each service varied considerably across hospitals. Understanding resource inputs and the varying contribution of these inputs by clinical condition is an important first step in developing effective cost control strategies.

Effects of hamstring stretching on passive muscle stiffness vary between hip flexion and knee extension maneuvers.

PubMed

Miyamoto, N; Hirata, K; Kanehisa, H

2017-01-01

The purpose of this study was to examine whether the effects of hamstring stretching on the passive stiffness of each of the long head of the biceps femoris (BFl), semitendinosus (ST), and semimembranosus (SM) vary between passive knee extension and hip flexion stretching maneuvers. In 12 male subjects, before and after five sets of 90 s static stretching, passive lengthening measurements where knee or hip joint was passively rotated to the maximal range of motion (ROM) were performed. During the passive lengthening, shear modulus of each muscle was measured by ultrasound shear wave elastography. Both stretching maneuvers significantly increased maximal ROM and decreased passive torque at a given joint angle. Passive knee extension stretching maneuver significantly reduced shear modulus at a given knee joint angle in all of BFl, ST, and SM. In contrast, the stretching effect by passive hip flexion maneuver was significant only in ST and SM. The present findings indicate that the effects of hamstring stretching on individual passive muscles' stiffness vary between passive knee extension and hip flexion stretching maneuvers. In terms of reducing the muscle stiffness of BFl, stretching of the hamstring should be performed by passive knee extension rather than hip flexion. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Exact reconstruction analysis/synthesis filter banks with time-varying filters

NASA Technical Reports Server (NTRS)

Arrowood, J. L., Jr.; Smith, M. J. T.

1993-01-01

This paper examines some of the analysis/synthesis issues associated with FIR time-varying filter banks where the filter bank coefficients are allowed to change in response to the input signal. Several issues are identified as being important in order to realize performance gains from time-varying filter banks in image coding applications. These issues relate to the behavior of the filters as transition from one set of filter banks to another occurs. Lattice structure formulations for the time varying filter bank problem are introduced and discussed in terms of their properties and transition characteristics.

Fostering significant learning in graduate nursing education.

PubMed

Marrocco, Geraldine F

2014-03-01

Faculty who want to energize graduate students with creative classes that lead to long-lasting learning will benefit by designing course objectives, learning activities, and assessment tools using Fink's taxonomy of significant learning and Wiggins's insights on performance-based or educative assessments. Research shows that course designs relying on content-driven lectures and written examinations do not promote significant learning among adult learners. This article reviews six types of significant learning using Fink's taxonomy and examines Wiggins's "backward" approach to designing courses using performance-based assessments that gauge true learning and learning that promotes a lasting change. When designing courses, educators should ask: "What do I really want students to get out of this course?" The answers will direct the design of objectives, learning activities, and assessment tools. Designing graduate courses using Fink's taxonomy and Wiggins's backward approach can lead to significant learning to better prepare nurse practitioners for the future of health care. Copyright 2014, SLACK Incorporated.

Nutrition activation and dietary intake disparities among US adults.

PubMed

Langellier, Brent A; Massey, Philip M

2016-12-01

To introduce the concept 'nutrition activation' (the use of health and nutrition information when making food and diet decisions) and to assess the extent to which nutrition activation varies across racial/ethnic groups and explains dietary disparities. Cross-sectional sample representative of adults in the USA. Primary outcome measures include daily energy intake and consumption of sugar-sweetened beverages (SSB), fast foods and sit-down restaurant foods as determined by two 24 h dietary recalls. We use bivariate statistics and multiple logistic and linear regression analyses to assess racial/ethnic disparities in nutrition activation and food behaviour outcomes. USA. Adult participants (n 7825) in the 2007-2010 National Health and Nutrition Examination Survey. Nutrition activation varies across racial/ethnic groups and is a statistically significant predictor of SSB, fast-food and restaurant-food consumption and daily energy intake. Based on the sample distribution, an increase from the 25th to 75th percentile in nutrition activation is associated with a decline of about 377 kJ (90 kcal)/d. Increased nutrition activation is associated with a larger decline in SSB consumption among whites than among blacks and foreign-born Latinos. Fast-food consumption is associated with a larger 'spike' in daily energy intake among blacks (+1582 kJ (+378 kcal)/d) than among whites (+678 kJ (+162 kcal)/d). Nutrition activation is an important but understudied determinant of energy intake and should be explicitly incorporated into obesity prevention interventions, particularly among racial/ethnic minorities.

Spatially varying dispersion to model breakthrough curves.

PubMed

Li, Guangquan

2011-01-01

Often the water flowing in a karst conduit is a combination of contaminated water entering at a sinkhole and cleaner water released from the limestone matrix. Transport processes in the conduit are controlled by advection, mixing (dilution and dispersion), and retention-release. In this article, a karst transport model considering advection, spatially varying dispersion, and dilution (from matrix seepage) is developed. Two approximate Green's functions are obtained using transformation of variables, respectively, for the initial-value problem and for the boundary-value problem. A numerical example illustrates that mixing associated with strong spatially varying conduit dispersion can cause strong skewness and long tailing in spring breakthrough curves. Comparison of the predicted breakthrough curve against that measured from a dye-tracing experiment between Ames Sink and Indian Spring, Northwest Florida, shows that the conduit dispersivity can be as large as 400 m. Such a large number is believed to imply strong solute interaction between the conduit and the matrix and/or multiple flow paths in a conduit network. It is concluded that Taylor dispersion is not dominant in transport in a karst conduit, and the complicated retention-release process between mobile- and immobile waters may be described by strong spatially varying conduit dispersion. Copyright © 2010 The Author(s). Journal compilation © 2010 National Ground Water Association.

Light sensitometry of mammography films at varying development temperatures and times

PubMed Central

Sharma, Reena; Sharma, Sunil Dutt; Mayya, Y. S.

2012-01-01

Kodak MinR-2000 mammography film is widely used for mammography imaging. The sensitometric indices like base plus fog level (B + F), maximum optical density (ODmax), average gradient (AG) and speed of this film at varying development temperatures and times were evaluated using a light sensitometer. Totally 33 film strips were cut from a single Kodak MinR-2000 mammography film box and exposed in a light sensitometer operated in the green light spectrum to produce a 21-step sensitometric strip. These exposed film strips were processed at temperatures in the range of 32°C–37°C in the step of 1°C and at processing times in the range of 1–6 minutes in the step of 1 minute. The results of the present study show that the measured base plus fog level of the mammography film was not affected much, whereas significant changes were seen in the ODmax, AG and speed with varying development temperatures and times. The ODmax values of the film were found in the range of 3.67–3.76, AG values were in the range of 2.48–3.4 and speed values were in the range of 0.015–0.0236 when the processing temperature was varied from 32°C to 37°C. With processing time variation from 1 to 6 minutes, the observed changes in ODmax values were in the range of 3.54-3.71, changes in AG were in the range of 2.66–3.27 and changes in speed were in the range of 0.011–0.025. Based on these observations, recommendations for optimum processing parameters to be used for this film are made. PMID:22363111

Feeding Practices of Mothers from Varied Income and Racial/Ethnic Groups.

PubMed

Worobey, John; Borrelli, Amanda; Espinosa, Carolina; Worobey, Harriet S

2013-11-01

Relatively few investigators have explored the role of maternal control in describing the feeding behavior of nonwhite parents of preschool-age children. The present study was conducted to examine if controlling feeding behaviors (i.e., restriction and pressuring) varied by income (middle vs. low) and race/ethnicity (white vs. Hispanic), and if they were associated with the BMI of their 4-year-old offspring. Responses to the "restriction" and "pressure to eat" variables of the Child Feeding Questionnaire were compared between 51 white middle-income mothers and 49 Hispanic low-income mothers. Mothers from both groups gave predominantly "neutral" ratings in their self-reports of feeding practices. However, relative to the Hispanic mothers, white mothers indicated significantly less restriction and pressure to eat. Higher child BMI was predicted by male gender and being Hispanic. The utility of maternal feeding practices in predicting child overweight is discussed, and the significant association between the conceptually different constructs of restriction and pressure to eat is examined.

Effects of location and timing of co-activated neurons in the auditory midbrain on cortical activity: implications for a new central auditory prosthesis

NASA Astrophysics Data System (ADS)

Straka, Małgorzata M.; McMahon, Melissa; Markovitz, Craig D.; Lim, Hubert H.

2014-08-01

Objective. An increasing number of deaf individuals are being implanted with central auditory prostheses, but their performance has generally been poorer than for cochlear implant users. The goal of this study is to investigate stimulation strategies for improving hearing performance with a new auditory midbrain implant (AMI). Previous studies have shown that repeated electrical stimulation of a single site in each isofrequency lamina of the central nucleus of the inferior colliculus (ICC) causes strong suppressive effects in elicited responses within the primary auditory cortex (A1). Here we investigate if improved cortical activity can be achieved by co-activating neurons with different timing and locations across an ICC lamina and if this cortical activity varies across A1. Approach. We electrically stimulated two sites at different locations across an isofrequency ICC lamina using varying delays in ketamine-anesthetized guinea pigs. We recorded and analyzed spike activity and local field potentials across different layers and locations of A1. Results. Co-activating two sites within an isofrequency lamina with short inter-pulse intervals (<5 ms) could elicit cortical activity that is enhanced beyond a linear summation of activity elicited by the individual sites. A significantly greater extent of normalized cortical activity was observed for stimulation of the rostral-lateral region of an ICC lamina compared to the caudal-medial region. We did not identify any location trends across A1, but the most cortical enhancement was observed in supragranular layers, suggesting further integration of the stimuli through the cortical layers. Significance. The topographic organization identified by this study provides further evidence for the presence of functional zones across an ICC lamina with locations consistent with those identified by previous studies. Clinically, these results suggest that co-activating different neural populations in the rostral-lateral ICC rather

Neurofunctional Differences Among Youth With and at Varying Risk for Developing Mania.

PubMed

Welge, Jeffrey A; Saliba, Lawrence J; Strawn, Jeffrey R; Eliassen, James C; Patino, L Rodrigo; Adler, Caleb M; Weber, Wade; Schneider, Marguerite Reid; Barzman, Drew H; Strakowski, Stephen M; DelBello, Melissa P; McNamara, Robert K

2016-11-01

To examine prefrontal and amygdala activation during emotional processing in youth with or at varying risk for developing mania to identify candidate central prodromal risk biomarkers. Four groups of medication-free adolescents (10-20 years old) participated: adolescents with first-episode bipolar I disorder (BP-I; n = 32), adolescents with a parent with bipolar disorder and a depressive disorder (at-risk depressed [ARD]; n = 32), healthy adolescents with a parent with bipolar disorder (at-risk healthy [ARH]; n = 32), and healthy adolescents with no personal or family history of psychiatric illness (healthy comparison [HC]; n = 32). Participants underwent functional magnetic resonance imaging while performing a continuous performance task with emotional and neutral distracters. Region-of-interest analyses were performed for the bilateral amygdala and for subregions of the ventrolateral prefrontal cortex and anterior cingulate cortex. Overall, no group differences in bilateral amygdala and ventrolateral prefrontal cortex (Brodmann area [BA] 45/47) activation during emotional or neutral stimuli were observed. The BP-I group exhibited lower right pregenual anterior cingulate cortex activation compared with the HC group, and activation in the left BA 44 was greater in the ARH and ARD groups compared with the HC group. BP-I and ARD groups exhibited blunted activation in the right BA 10 compared with the ARH group. During emotional processing, amygdala and ventrolateral prefrontal cortex (BA 45/47) activation does not differ in youth with or at increasing risk for BP-I. However, blunted pregenual anterior cingulate cortex activation in first-episode mania could represent an illness biomarker, and greater prefrontal BA 10 and BA 44 activations in at-risk youth could represent a biomarker of risk or resilience warranting additional investigation in prospective longitudinal studies. Copyright © 2016 American Academy of Child and Adolescent Psychiatry. Published by

Non-minimally coupled varying constants quantum cosmologies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balcerzak, Adam, E-mail: abalcerz@wmf.univ.szczecin.pl

We consider gravity theory with varying speed of light and varying gravitational constant. Both constants are represented by non-minimally coupled scalar fields. We examine the cosmological evolution in the near curvature singularity regime. We find that at the curvature singularity the speed of light goes to infinity while the gravitational constant vanishes. This corresponds to the Newton's Mechanics limit represented by one of the vertex of the Bronshtein-Zelmanov-Okun cube [1,2]. The cosmological evolution includes both the pre-big-bang and post-big-bang phases separated by the curvature singularity. We also investigate the quantum counterpart of the considered theory and find the probability ofmore » transition of the universe from the collapsing pre-big-bang phase to the expanding post-big-bang phase.« less

RPA-Mediated Unfolding of Systematically Varying G-Quadruplex Structures

PubMed Central

Ray, Sujay; Qureshi, Mohammad H.; Malcolm, Dominic W.; Budhathoki, Jagat B.; Çelik, Uğur; Balci, Hamza

2013-01-01

G-quadruplex (GQ) is a noncanonical nucleic acid structure that is formed by guanine rich sequences. Unless it is destabilized by proteins such as replication protein A (RPA), GQ could interfere with DNA metabolic functions, such as replication or repair. We studied RPA-mediated GQ unfolding using single-molecule FRET on two groups of GQ structures that have different loop lengths and different numbers of G-tetrad layers. We observed a linear increase in the steady-state stability of the GQ against RPA-mediated unfolding with increasing number of layers or decreasing loop length. The stability demonstrated by different GQ structures varied by at least three orders of magnitude. Those with shorter loops (less than three nucleotides long) or a greater number of layers (more than three layers) maintained a significant folded population even at physiological RPA concentration (≈1 μM), raising the possibility of physiological viability of such GQ structures. Finally, we measured the transition time between the start and end of the RPA-mediated GQ unfolding process to be 0.35 ± 0.10 s for all GQ constructs we studied, despite significant differences in their steady-state stabilities. We propose a two-step RPA-mediated GQ unfolding mechanism that is consistent with our observations. PMID:23708363

Predictors of BMI Vary along the BMI Range of German Adults – Results of the German National Nutrition Survey II

PubMed Central

Moon, Kilson; Krems, Carolin; Heuer, Thorsten; Roth, Alexander; Hoffmann, Ingrid

2017-01-01

Objective The objective of the study was to identify predictors of BMI in German adults by considering the BMI distribution and to determine whether the association between BMI and its predictors varies along the BMI distribution. Methods The sample included 9,214 adults aged 18–80 years from the German National Nutrition Survey II (NVS II). Quantile regression analyses were conducted to examine the association between BMI and the following predictors: age, sports activities, socio-economic status (SES), healthy eating index-NVS II (HEI-NVS II), dietary knowledge, sleeping duration and energy intake as well as status of smoking, partner relationship and self-reported health. Results Age, SES, self-reported health status, sports activities and energy intake were the strongest predictors of BMI. The important outcome of this study is that the association between BMI and its predictors varies along the BMI distribution. Especially, energy intake, health status and SES were marginally associated with BMI in normal-weight subjects; this relationships became stronger in the range of overweight, and were strongest in the range of obesity. Conclusions Predictors of BMI and the strength of these associations vary across the BMI distribution in German adults. Consequently, to identify predictors of BMI, the entire BMI distribution should be considered. PMID:28219069

The role of circulating sex hormones in menstrual cycle dependent modulation of pain-related brain activation

PubMed Central

Veldhuijzen, Dieuwke S.; Keaser, Michael L.; Traub, Deborah S.; Zhuo, Jiachen; Gullapalli, Rao P.; Greenspan, Joel D.

2013-01-01

Sex differences in pain sensitivity have been consistently found but the basis for these differences is incompletely understood. The present study assessed how pain-related neural processing varies across the menstrual cycle in normally cycling, healthy females, and whether menstrual cycle effects are based on fluctuating sex hormone levels. Fifteen subjects participated in four test sessions during their menstrual, mid-follicular, ovulatory, and midluteal phases. Brain activity was measured while nonpainful and painful stimuli were applied with a pressure algometer. Serum hormone levels confirmed that scans were performed at appropriate cycle phases in 14 subjects. No significant cycle phase differences were found for pain intensity or unpleasantness ratings of stimuli applied during fMRI scans. However, lower pressure pain thresholds were found for follicular compared to other phases. Pain-specific brain activation was found in several regions traditionally associated with pain processing, including the medial thalamus, anterior and mid-insula, mid-cingulate, primary and secondary somatosensory cortices, cerebellum, and frontal regions. The inferior parietal lobule, occipital gyrus, cerebellum and several frontal regions demonstrated interaction effects between stimulus level and cycle phase, indicating differential processing of pain-related responses across menstrual cycle phases. Correlational analyses indicated that cycle-related changes in pain sensitivity measures and brain activation were only partly explained by varying sex hormone levels. These results show that pain-related cerebral activation varies significantly across the menstrual cycle, even when perceived pain intensity and unpleasantness remain constant. The involved brain regions suggest that cognitive pain or more general bodily awareness systems are most susceptible to menstrual cycle effects. PMID:23528204

Innovative Varied-Fidelity Simulation Mobile Teaching Cart and Education Project.

PubMed

Harding, Andrew D; Cullinane Whalen, Kathryn; Silverman, Bradley S

2015-09-01

The use of a varied-fidelity simulation mobile teaching cart is a teaching tool that offers unique advantages in the acute care setting. The cart is used to demonstrate the use of patient monitoring devices, and there are a variety of software tools available with the monitoring technology to ensure that the outputs, including electrocardiographic waves, are analyzed appropriately by nursing staff using this varied-fidelity simulation mobile teaching cart. Bringing varied-fidelity simulation to the nurses' work area is a unique application setting. Copyright © 2015 Emergency Nurses Association. Published by Elsevier Inc. All rights reserved.

Varying ultrasound power level to distinguish surgical instruments and tissue.

PubMed

Ren, Hongliang; Anuraj, Banani; Dupont, Pierre E

2018-03-01

We investigate a new framework of surgical instrument detection based on power-varying ultrasound images with simple and efficient pixel-wise intensity processing. Without using complicated feature extraction methods, we identified the instrument with an estimated optimal power level and by comparing pixel values of varying transducer power level images. The proposed framework exploits the physics of ultrasound imaging system by varying the transducer power level to effectively distinguish metallic surgical instruments from tissue. This power-varying image-guidance is motivated from our observations that ultrasound imaging at different power levels exhibit different contrast enhancement capabilities between tissue and instruments in ultrasound-guided robotic beating-heart surgery. Using lower transducer power levels (ranging from 40 to 75% of the rated lowest ultrasound power levels of the two tested ultrasound scanners) can effectively suppress the strong imaging artifacts from metallic instruments and thus, can be utilized together with the images from normal transducer power levels to enhance the separability between instrument and tissue, improving intraoperative instrument tracking accuracy from the acquired noisy ultrasound volumetric images. We performed experiments in phantoms and ex vivo hearts in water tank environments. The proposed multi-level power-varying ultrasound imaging approach can identify robotic instruments of high acoustic impedance from low-signal-to-noise-ratio ultrasound images by power adjustments.

Barnacle Geese Achieve Significant Energetic Savings by Changing Posture

PubMed Central

Tickle, Peter G.; Nudds, Robert L.; Codd, Jonathan R.

2012-01-01

Here we report the resting metabolic rate in barnacle geese (Branta leucopsis) and provide evidence for the significant energetic effect of posture. Under laboratory conditions flow-through respirometry together with synchronous recording of behaviour enabled a calculation of how metabolic rate varies with posture. Our principal finding is that standing bipedally incurs a 25% increase in metabolic rate compared to birds sitting on the ground. In addition to the expected decrease in energy consumption of hindlimb postural muscles when sitting, we hypothesise that a change in breathing mechanics represents one potential mechanism for at least part of the observed difference in energetic cost. Due to the significant effect of posture, future studies of resting metabolic rates need to take into account and/or report differences in posture. PMID:23071672

The chronnectome: time-varying connectivity networks as the next frontier in fMRI data discovery.

PubMed

Calhoun, Vince D; Miller, Robyn; Pearlson, Godfrey; Adalı, Tulay

2014-10-22

Recent years have witnessed a rapid growth of interest in moving functional magnetic resonance imaging (fMRI) beyond simple scan-length averages and into approaches that capture time-varying properties of connectivity. In this Perspective we use the term "chronnectome" to describe metrics that allow a dynamic view of coupling. In the chronnectome, coupling refers to possibly time-varying levels of correlated or mutually informed activity between brain regions whose spatial properties may also be temporally evolving. We primarily focus on multivariate approaches developed in our group and review a number of approaches with an emphasis on matrix decompositions such as principle component analysis and independent component analysis. We also discuss the potential these approaches offer to improve characterization and understanding of brain function. There are a number of methodological directions that need to be developed further, but chronnectome approaches already show great promise for the study of both the healthy and the diseased brain.

Accelerometer's position independent physical activity recognition system for long-term activity monitoring in the elderly.

PubMed

Khan, Adil Mehmood; Lee, Young-Koo; Lee, Sungyoung; Kim, Tae-Seong

2010-12-01

Mobility is a good indicator of health status and thus objective mobility data could be used to assess the health status of elderly patients. Accelerometry has emerged as an effective means for long-term physical activity monitoring in the elderly. However, the output of an accelerometer varies at different positions on a subject's body, even for the same activity, resulting in high within-class variance. Existing accelerometer-based activity recognition systems thus require firm attachment of the sensor to a subject's body. This requirement makes them impractical for long-term activity monitoring during unsupervised free-living as it forces subjects into a fixed life pattern and impede their daily activities. Therefore, we introduce a novel single-triaxial-accelerometer-based activity recognition system that reduces the high within-class variance significantly and allows subjects to carry the sensor freely in any pocket without its firm attachment. We validated our system using seven activities: resting (lying/sitting/standing), walking, walking-upstairs, walking-downstairs, running, cycling, and vacuuming, recorded from five positions: chest pocket, front left trousers pocket, front right trousers pocket, rear trousers pocket, and inner jacket pocket. Its simplicity, ability to perform activities unimpeded, and an average recognition accuracy of 94% make our system a practical solution for continuous long-term activity monitoring in the elderly.

Joint optimization of green vehicle scheduling and routing problem with time-varying speeds.

PubMed

Zhang, Dezhi; Wang, Xin; Li, Shuangyan; Ni, Nan; Zhang, Zhuo

2018-01-01

Based on an analysis of the congestion effect and changes in the speed of vehicle flow during morning and evening peaks in a large- or medium-sized city, the piecewise function is used to capture the rules of the time-varying speed of vehicles, which are very important in modelling their fuel consumption and CO2 emission. A joint optimization model of the green vehicle scheduling and routing problem with time-varying speeds is presented in this study. Extra wages during nonworking periods and soft time-window constraints are considered. A heuristic algorithm based on the adaptive large neighborhood search algorithm is also presented. Finally, a numerical simulation example is provided to illustrate the optimization model and its algorithm. Results show that, (1) the shortest route is not necessarily the route that consumes the least energy, (2) the departure time influences the vehicle fuel consumption and CO2 emissions and the optimal departure time saves on fuel consumption and reduces CO2 emissions by up to 5.4%, and (3) extra driver wages have significant effects on routing and departure time slot decisions.

Mixed-effects varying-coefficient model with skewed distribution coupled with cause-specific varying-coefficient hazard model with random-effects for longitudinal-competing risks data analysis.

PubMed

Lu, Tao; Wang, Min; Liu, Guangying; Dong, Guang-Hui; Qian, Feng

2016-01-01

It is well known that there is strong relationship between HIV viral load and CD4 cell counts in AIDS studies. However, the relationship between them changes during the course of treatment and may vary among individuals. During treatments, some individuals may experience terminal events such as death. Because the terminal event may be related to the individual's viral load measurements, the terminal mechanism is non-ignorable. Furthermore, there exists competing risks from multiple types of events, such as AIDS-related death and other death. Most joint models for the analysis of longitudinal-survival data developed in literatures have focused on constant coefficients and assume symmetric distribution for the endpoints, which does not meet the needs for investigating the nature of varying relationship between HIV viral load and CD4 cell counts in practice. We develop a mixed-effects varying-coefficient model with skewed distribution coupled with cause-specific varying-coefficient hazard model with random-effects to deal with varying relationship between the two endpoints for longitudinal-competing risks survival data. A fully Bayesian inference procedure is established to estimate parameters in the joint model. The proposed method is applied to a multicenter AIDS cohort study. Various scenarios-based potential models that account for partial data features are compared. Some interesting findings are presented.

A sensitivity analysis on the variability in accelerometer data processing for monitoring physical activity.

PubMed

Lee, Paul H

2015-02-01

Accelerometers are gaining popularity for measuring physical activity, but there are many different ways to process accelerometer data. A sensitivity analysis was conducted to study the effect of varying accelerometer data processing protocols on estimating the association between PA level and socio-demographic characteristics using the National Health and Nutrition Examination Survey (NHANES) accelerometer data. The NHANES waves 2003-2004 and 2005-2006 accelerometer data (n=14,072) were used to investigate the effect of changing the accelerometer non-wearing time and valid day definitions on the demographic composition of the filtered datasets and the association between physical activity (PA) and socio-demographic characteristics (sex, age, race, educational level, marital status). Under different filtering rules (minimum number of valid day and definition of non-wear time), the demographic characteristics of the final sample varied. The proportion of participants aged 20-29 decreased from 18.9% to 15.8% when the minimum number of valid days required increased from 1 to 4 (p for trend<0.001), whereas that for aged ≥70 years increased from 18.9% to 20.6% (p for trend<0.001). Furthermore, with different filters, the effect of these demographic variables and PA varied, with some variables being significant under certain filtering rules but becoming insignificant under some other rules. The sensitivity analysis showed that the significance of the association between socio-demographic variables and PA could be varied with the definition of non-wearing time and minimum number of valid days. Copyright © 2014 Elsevier B.V. All rights reserved.

Allometric Scaling of the Active Hematopoietic Stem Cell Pool across Mammals

PubMed Central

Dingli, David; Pacheco, Jorge M.

2006-01-01

Background Many biological processes are characterized by allometric relations of the type Y = Y 0 Mb between an observable Y and body mass M, which pervade at multiple levels of organization. In what regards the hematopoietic stem cell pool, there is experimental evidence that the size of the hematopoietic stem cell pool is conserved in mammals. However, demands for blood cell formation vary across mammals and thus the size of the active stem cell compartment could vary across species. Methodology/Principle Findings Here we investigate the allometric scaling of the hematopoietic system in a large group of mammalian species using reticulocyte counts as a marker of the active stem cell pool. Our model predicts that the total number of active stem cells, in an adult mammal, scales with body mass with the exponent ¾. Conclusion/Significance The scaling predicted here provides an intuitive justification of the Hayflick hypothesis and supports the current view of a small active stem cell pool supported by a large, quiescent reserve. The present scaling shows excellent agreement with the available (indirect) data for smaller mammals. The small size of the active stem cell pool enhances the role of stochastic effects in the overall dynamics of the hematopoietic system. PMID:17183646

Cell-Selective Biological Activity of Rhodium Metalloinsertors Correlates with Subcellular Localization

PubMed Central

Komor, Alexis C.; Schneider, Curtis J.; Weidmann, Alyson G.; Barton, Jacqueline K.

2013-01-01

Deficiencies in the mismatch repair (MMR) pathway are associated with several types of cancers, as well as resistance to commonly used chemotherapeutics. Rhodium metalloinsertors have been found to bind DNA mismatches with high affinity and specificity in vitro, and also exhibit cell-selective cytotoxicity, targeting MMR-deficient cells over MMR-proficient cells. Ten distinct metalloinsertors with varying lipophilicities have been synthesized and their mismatch binding affinities and biological activities determined. Although DNA photocleavage experiments demonstrate that their binding affinities are quite similar, their cell-selective antiproliferative and cytotoxic activities vary significantly. Inductively coupled plasma mass spectrometry (ICP-MS) experiments have uncovered a relationship between the subcellular distribution of these metalloinsertors and their biological activities. Specifically, we find that all of our metalloinsertors localize in the nucleus at sufficient concentrations for binding to DNA mismatches. However, the metalloinsertors with high rhodium localization in the mitochondria show toxicity that is not selective for MMR-deficient cells, whereas metalloinsertors with less mitochondrial rhodium show activity that is highly selective for MMR-deficient versus proficient cells. This work supports the notion that specific targeting of the metalloinsertors to nuclear DNA gives rise to their cell-selective cytotoxic and antiproliferative activities. The selectivity in cellular targeting depends upon binding to mismatches in genomic DNA. PMID:23137296

The Thermal Collector With Varied Glass Covers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Luminosu, I.; Pop, N.

2010-08-04

The thermal collector with varied glass covers represents an innovation realized in order to build a collector able to reach the desired temperature by collecting the solar radiation from the smallest surface, with the highest efficiency. In the case of the thermal collector with variable cover glasses, the number of the glass plates covering the absorber increases together with the length of the circulation pipe for the working fluid. The thermal collector with varied glass covers compared to the conventional collector better meet user requirements because: for the same temperature increase, has the collecting area smaller; for the same collectionmore » area, realizes the highest temperature increase and has the highest efficiency. This works is addressed to researchers in the solar energy and to engineers responsible with air-conditioning systems design or industrial and agricultural products drying.« less

The Thermal Collector With Varied Glass Covers

NASA Astrophysics Data System (ADS)

Luminosu, I.; Pop, N.

2010-08-01

The thermal collector with varied glass covers represents an innovation realized in order to build a collector able to reach the desired temperature by collecting the solar radiation from the smallest surface, with the highest efficiency. In the case of the thermal collector with variable cover glasses, the number of the glass plates covering the absorber increases together with the length of the circulation pipe for the working fluid. The thermal collector with varied glass covers compared to the conventional collector better meet user requirements because: for the same temperature increase, has the collecting area smaller; for the same collection area, realizes the highest temperature increase and has the highest efficiency. This works is addressed to researchers in the solar energy and to engineers responsible with air-conditioning systems design or industrial and agricultural products drying.

Status of the Topside Vary-Chap Ionospheric Model

NASA Astrophysics Data System (ADS)

Reinisch, Bodo; Nsumei, Patrick; Huang, Xueqin; Bilitza, Dieter

Status of the Topside Vary-Chap Ionospheric Model The general alpha-Chapman function for a multi-constituent gas which includes a continuously varying scale height and was therefore dubbed the Vary-Chap function, can present the topside electron density profiles in analytical form. The Vary-Chap profile is defined by the scale height function H(h) and the height and density of the F2 layer peak. By expressing 80,000 ISIS-2 measured topside density profiles as Vary-Chap functions we derived 80,000 scale height functions, which form the basis for the topside density profile modeling. The normalized scale height profiles Hn = H(h)/Hm were grouped according to season, MLAT, and MLT for each 50 km height bin from 200 km to 1400 km, and the median, lower, and upper quartiles for each bin were calculated. Hm is the scale height at the F2 layer peak. The resulting Hn functions are modeled in terms of hyperbolic tangent functions using 5 parameters that are determined by multivariate least squares, including the transition height hT where the scale height gradient has a maximum. These normalized scale height functions, representing the model of the topside electron density profiles from hmF2 to 1,400 km altitude, are independent of hmF2 and NmF2 and can therefore be directly used for the topside Ne profile in IRI. Similarly, this model can extend measured bottomside profiles to the topside, replacing the simple alpha-Chapman function with constant scale height that is currently used for construction of the topside profile in the Digisondes / ARTIST of the Global Ionospheric Radio Observatory (GIRO). It turns out that Hm(top) calculated from the topside profiles is generally several times larger than Hm(bot) derived from the bottomside profiles. This follows necessarily from the difference in the definition of the scale height functions for the topside and bottomside profiles. The diurnal variations of the ratio Hm(top) / Hm(bot) has been determined for different latitudes

Comparison of phytochemical profiles, antioxidant and cellular antioxidant activities of different varieties of blueberry (Vaccinium spp.).

PubMed

Wang, Huailing; Guo, Xinbo; Hu, Xiaodan; Li, Tong; Fu, Xiong; Liu, Rui Hai

2017-02-15

Numerous reports have demonstrated that the consumption of fruits and vegetables is beneficial for the human health. Blueberries, in particular, are rich in phytochemicals including free and bound forming. Phytochemical profiles of 14 varieties of blueberry were compared in this study. 12 compounds were analyzed and had significant changes in blueberry fruits. Total antioxidant activities in different blueberry varieties varied about 2.6times by oxygen radical absorbance capacity (ORAC) assay, and 2times by peroxyl radical scavenging capacity (PSC) assay. The cellular antioxidant activities (CAA) in different varieties varied about 3.9times without phosphate buffer saline (PBS) wash, and 4.7times with PBS wash by CAA assay. Blueberry extracts had potent antiproliferative activities against HepG2 human liver cancer cells, indicating the potential protective benefits associated with their use as functional foods. The anti-proliferative activity was observed to be dose-dependent in blueberry extracts. Copyright © 2016 Elsevier Ltd. All rights reserved.

Comparative study of carbonic anhydrase activity in waters among different geological eco-environments of Yangtze River basin and its ecological significance.

PubMed

Nzung'a, Sila Onesmus; Pan, Weizhi; Shen, Taiming; Li, Wei; Qin, Xiaoqun; Wang, Chenwei; Zhang, Liankai; Yu, Longjiang

2018-04-01

This study provides the presence of carbonic anhydrase (CA) activity in waters of the Yangtze River basin, China, as well as the correlation of CA activity with HCO 3 - concentration and CO 2 sink flux. Different degrees of CA activity could be detected in almost all of the water samples from different geological eco-environments in all four seasons. The CA activity of water samples from karst areas was significantly higher than from non-karst areas (PP3 - concentration (r=0.672, P2 sink flux (r=0.602, P=0.076) in karst areas. This suggests that CA in waters might have a promoting effect on carbon sinks for atmospheric CO 2 in karst river basins. In conditions of similar geological type, higher CA activity was generally detected in water samples taken from areas that exhibited better eco-environments, implying that the CA activity index of waters could be used as an indicator for monitoring ecological environments and protection of river basins. These findings suggest that the role of CA in waters in the karst carbon sink potential of river basins is worthy of further in-depth studies. Copyright © 2017. Published by Elsevier B.V.

Active dynamics of colloidal particles in time-varying laser speckle patterns

PubMed Central

Bianchi, Silvio; Pruner, Riccardo; Vizsnyiczai, Gaszton; Maggi, Claudio; Di Leonardo, Roberto

2016-01-01

Colloidal particles immersed in a dynamic speckle pattern experience an optical force that fluctuates both in space and time. The resulting dynamics presents many interesting analogies with a broad class of non-equilibrium systems like: active colloids, self propelled microorganisms, transport in dynamical intracellular environments. Here we show that the use of a spatial light modulator allows to generate light fields that fluctuate with controllable space and time correlations and a prescribed average intensity profile. In particular we generate ring-shaped random patterns that can confine a colloidal particle over a quasi one-dimensional random energy landscape. We find a mean square displacement that is diffusive at both short and long times, while a superdiffusive or subdiffusive behavior is observed at intermediate times depending on the value of the speckles correlation time. We propose two alternative models for the mean square displacement in the two limiting cases of a short or long speckles correlation time. A simple interpolation formula is shown to account for the full phenomenology observed in the mean square displacement across the entire range from fast to slow fluctuating speckles. PMID:27279540

Brain activations evoked by tactile stimulation varies with the intensity and not with number of receptive fields stimulated: An fMRI study

NASA Astrophysics Data System (ADS)

Ramirez Garzón, Y. T.; Pasaye, E. H.; Barrios, F. A.

2014-11-01

Using functional Magnetic Resonance Imaging (fMRI) it is possible to study the functional anatomy of primary cortices. Cortical representations in the primary somatosensory cortex have shown discrepancies between activations related to the same body region in some studies; these differences have been more pronounced for lower limb representations. The aim of this study was to observe the influence of the tactile stimulus intensity in somatosensory cortical responses using fMRI. Based in the sensitivity and pain threshold of each subject, we used Von Frey filaments for stimulate 12 control subject in three receptive fields on the right thigh. One filament near to sensitivity threshold (VFS), other close to pain threshold (VFP) and one intermediate filament between the two previous thresholds (VFI). The tactile stimulation with VFS produced no activation on SI, while that the contralateral SI was activated by stimulation with VFI in 5 subjects and with the stimulation of VFP in all subjects. Second level statistical analysis showed significant differences between SI activations related to the stimulation with VFP and VFI (VFP > VFI), in the comparison between the applied different intensities, a small cluster of activation was observed on SI for the unique possible contrast (VFP > VFI). The time course per trial for each subject was extracted and averaged to extract the activation in the contralateral SI and compared across the stimulus modalities, between the sites of field receptive stimulated and the intensities used. The time course of tactile stimulus responses revealed a consistent single peak of activity per cycle (30 s), approximately 12 s after the onset of the stimulus, with exception of the VFI stimulation,_which showed the peak at 10 s. Thus, our results indicate that the cortical representation of a tactile stimulus with fMRI is modulated for the intensity of the stimulus applied.

Sensor trustworthiness in uncertain time varying stochastic environments

NASA Astrophysics Data System (ADS)

Verma, Ajay; Fernandes, Ronald; Vadakkeveedu, Kalyan

2011-06-01

Persistent surveillance applications require unattended sensors deployed in remote regions to track and monitor some physical stimulant of interest that can be modeled as output of time varying stochastic process. However, the accuracy or the trustworthiness of the information received through a remote and unattended sensor and sensor network cannot be readily assumed, since sensors may get disabled, corrupted, or even compromised, resulting in unreliable information. The aim of this paper is to develop information theory based metric to determine sensor trustworthiness from the sensor data in an uncertain and time varying stochastic environment. In this paper we show an information theory based determination of sensor data trustworthiness using an adaptive stochastic reference sensor model that tracks the sensor performance for the time varying physical feature, and provides a baseline model that is used to compare and analyze the observed sensor output. We present an approach in which relative entropy is used for reference model adaptation and determination of divergence of the sensor signal from the estimated reference baseline. We show that that KL-divergence is a useful metric that can be successfully used in determination of sensor failures or sensor malice of various types.

Network Inference via the Time-Varying Graphical Lasso

PubMed Central

Hallac, David; Park, Youngsuk; Boyd, Stephen; Leskovec, Jure

2018-01-01

Many important problems can be modeled as a system of interconnected entities, where each entity is recording time-dependent observations or measurements. In order to spot trends, detect anomalies, and interpret the temporal dynamics of such data, it is essential to understand the relationships between the different entities and how these relationships evolve over time. In this paper, we introduce the time-varying graphical lasso (TVGL), a method of inferring time-varying networks from raw time series data. We cast the problem in terms of estimating a sparse time-varying inverse covariance matrix, which reveals a dynamic network of interdependencies between the entities. Since dynamic network inference is a computationally expensive task, we derive a scalable message-passing algorithm based on the Alternating Direction Method of Multipliers (ADMM) to solve this problem in an efficient way. We also discuss several extensions, including a streaming algorithm to update the model and incorporate new observations in real time. Finally, we evaluate our TVGL algorithm on both real and synthetic datasets, obtaining interpretable results and outperforming state-of-the-art baselines in terms of both accuracy and scalability. PMID:29770256

How Do Parenting Concepts Vary within and between the Families?

ERIC Educational Resources Information Center

Roskam, Isabelle; Meunier, Jean Christophe

2009-01-01

How do parenting concepts vary within and between the families? The present study regards parenting as a complex family process by considering three concepts of parenting: styles, differential treatment and coparenting consistency. A main question was addressed: whether and how these parenting concepts vary within the families towards siblings or…

Asymptotic theory of time-varying social networks with heterogeneous activity and tie allocation.

PubMed

Ubaldi, Enrico; Perra, Nicola; Karsai, Márton; Vezzani, Alessandro; Burioni, Raffaella; Vespignani, Alessandro

2016-10-24

The dynamic of social networks is driven by the interplay between diverse mechanisms that still challenge our theoretical and modelling efforts. Amongst them, two are known to play a central role in shaping the networks evolution, namely the heterogeneous propensity of individuals to i) be socially active and ii) establish a new social relationships with their alters. Here, we empirically characterise these two mechanisms in seven real networks describing temporal human interactions in three different settings: scientific collaborations, Twitter mentions, and mobile phone calls. We find that the individuals' social activity and their strategy in choosing ties where to allocate their social interactions can be quantitatively described and encoded in a simple stochastic network modelling framework. The Master Equation of the model can be solved in the asymptotic limit. The analytical solutions provide an explicit description of both the system dynamic and the dynamical scaling laws characterising crucial aspects about the evolution of the networks. The analytical predictions match with accuracy the empirical observations, thus validating the theoretical approach. Our results provide a rigorous dynamical system framework that can be extended to include other processes shaping social dynamics and to generate data driven predictions for the asymptotic behaviour of social networks.

Asymptotic theory of time-varying social networks with heterogeneous activity and tie allocation

NASA Astrophysics Data System (ADS)

Ubaldi, Enrico; Perra, Nicola; Karsai, Márton; Vezzani, Alessandro; Burioni, Raffaella; Vespignani, Alessandro

2016-10-01

The dynamic of social networks is driven by the interplay between diverse mechanisms that still challenge our theoretical and modelling efforts. Amongst them, two are known to play a central role in shaping the networks evolution, namely the heterogeneous propensity of individuals to i) be socially active and ii) establish a new social relationships with their alters. Here, we empirically characterise these two mechanisms in seven real networks describing temporal human interactions in three different settings: scientific collaborations, Twitter mentions, and mobile phone calls. We find that the individuals’ social activity and their strategy in choosing ties where to allocate their social interactions can be quantitatively described and encoded in a simple stochastic network modelling framework. The Master Equation of the model can be solved in the asymptotic limit. The analytical solutions provide an explicit description of both the system dynamic and the dynamical scaling laws characterising crucial aspects about the evolution of the networks. The analytical predictions match with accuracy the empirical observations, thus validating the theoretical approach. Our results provide a rigorous dynamical system framework that can be extended to include other processes shaping social dynamics and to generate data driven predictions for the asymptotic behaviour of social networks.

Monopoly models with time-varying demand function

NASA Astrophysics Data System (ADS)

Cavalli, Fausto; Naimzada, Ahmad

2018-05-01

We study a family of monopoly models for markets characterized by time-varying demand functions, in which a boundedly rational agent chooses output levels on the basis of a gradient adjustment mechanism. After presenting the model for a generic framework, we analytically study the case of cyclically alternating demand functions. We show that both the perturbation size and the agent's reactivity to profitability variation signals can have counterintuitive roles on the resulting period-2 cycles and on their stability. In particular, increasing the perturbation size can have both a destabilizing and a stabilizing effect on the resulting dynamics. Moreover, in contrast with the case of time-constant demand functions, the agent's reactivity is not just destabilizing, but can improve stability, too. This means that a less cautious behavior can provide better performance, both with respect to stability and to achieved profits. We show that, even if the decision mechanism is very simple and is not able to always provide the optimal production decisions, achieved profits are very close to those optimal. Finally, we show that in agreement with the existing empirical literature, the price series obtained simulating the proposed model exhibit a significant deviation from normality and large volatility, in particular when underlying deterministic dynamics become unstable and complex.

Integrating the Public in Mosquito Management: Active Education by Community Peers Can Lead to Significant Reduction in Peridomestic Container Mosquito Habitats

PubMed Central

Healy, Kristen; Hamilton, George; Crepeau, Taryn; Healy, Sean; Unlu, Isik; Farajollahi, Ary; Fonseca, Dina M.

2014-01-01

Mosquito species that utilize peridomestic containers for immature development are commonly aggressive human biters, and because they often reach high abundance, create significant nuisance. One of these species, the Asian tiger mosquito Aedes albopictus, is an important vector of emerging infectious diseases, such as dengue, chikungunya, and Zika fevers. Integrated mosquito management (IMM) of Ae. albopictus is particularly difficult because it requires access to private yards in urban and suburban residences. It has become apparent that in the event of a public health concern due to this species, homeowners will have to be active participants in the control process by reducing mosquito habitats in their properties, an activity known as source reduction. However, limited attempts at quantifying the effect of source reduction by homeowners have had mixed results. Of note, many mosquito control programs in the US have some form of education outreach, however the primary approach is often passive focusing on the distribution of education materials as flyers. In 2010, we evaluated the use of active community peer education in a source reduction program, using AmeriCorps volunteers. The volunteers were mobilized over a 4-week period, in two areas with approximately 1,000 residences each in urban Mercer and suburban Monmouth counties in New Jersey, USA. The volunteers were first provided training on peridomestic mosquitoes and on basic approaches to reducing the number of container habitats for mosquito larvae in backyards. Within the two treatment areas the volunteers successfully engaged 758 separate homes. Repeated measures analysis of variance showed a significant reduction in container habitats in the sites where the volunteers actively engaged the community compared to untreated control areas in both counties. Our results suggest that active education using community peer educators can be an effective means of source reduction, and a critical tool in the arsenal

Toroidal varied-line space (TVLS) gratings

NASA Astrophysics Data System (ADS)

Thomas, Roger J.

2003-02-01

It is a particular challenge to develop a stigmatic spectrograph for EUV wavelengths since the very low normal-incidence reflectance of standard materials most often requires that the design be restricted to a single optical element which must simultaneously provide both re-imaging and spectral dispersion. This problem has been solved in the past by the use of toroidal gratings with uniform line-space rulings (TULS). A number of solar EUV spectrographs have been based on such designs, including SOHO/CDS, Solar-B/EIS, and the sounding rockets SERTS and EUNIS. More recently, Kita, Harada, and collaborators have developed the theory of spherical gratings with varied line-space rulings (SVLS) operated at unity magnification, which have been flown on several astronomical satellite missions. These ideas are now combined into a spectrograph concept that considers varied-line space grooves ruled onto toroidal gratings. Such TVLS designs are found to provide excellent imaging even at very large spectrograph magnifications and beam-speeds, permitting extremely high-quality performance in remarkably compact instrument packages. Optical characteristics of two solar spectrographs based on this concept are described: SUMI, proposed as a sounding rocket experiment, and NEXUS, proposed for the Solar Dynamics Observatory mission.

Toroidal Varied-Line Space (TVLS) Gratings

NASA Technical Reports Server (NTRS)

Thomas, Roger J.; Oegerle, William (Technical Monitor)

2002-01-01

It is a particular challenge to develop a stigmatic spectrograph for XUV wavelengths since the very low normal-incidence reflectance of standard materials most often requires that the design be restricted to a single optical element which must simultaneously provide both re-imaging and spectral dispersion. This problem has been solved in the past by the use of toroidal gratings with uniform line-spaced rulings (TULS). A number of solar EUV (Extreme Ultraviolet) spectrometers have been based on such designs, including SOHO/CDS, Solar-B/EIS, and the sounding rockets SERTS and EUNIS. More recently, Kita, Harada, and collaborators have developed the theory of spherical gratings with varied line-space rulings (SVLS) operated at unity magnification, which have been flown on several astronomical satellite missions. We now combine these ideas into a spectrometer concept that puts varied-line space rulings onto toroidal gratings. Such TVLS designs are found to provide excellent imaging even at very large spectrograph magnifications and beam-speeds, permitting extremely high-quality performance in remarkably compact instrument packages. Optical characteristics of two solar spectrometers based on this concept are described: SUMI, proposed as a sounding rocket experiment, and NEXUS, proposed for the Solar Dynamics Observatory mission.

Identifying Life from Varying Atmospheres

NASA Astrophysics Data System (ADS)

Kohler, Susanna

2018-06-01

Theres no hiding changes in Earths atmosphere over the seasons are a dead giveaway to the fact that Earth hosts life. Now a new study explores whether we might use atmospheric seasonality like Earths to detect life on other planets.Looking for ChangeMost of the searches for life beyond our planet focus on identifying static biosignatures, like the presence of methane or large amounts of oxygen in an exoplanetary atmosphere. This approach suffers from many ambiguities, however including a high likelihood of false positives (processes that chemically mimic life signatures but arent life) and false negatives (non-detections despite the presence of life).Earths atmospheric carbon dioxide (top) and methane (bottom) levels vary seasonally, as seen in these data from NOAAs Earth System Research Laboratory. [Olson et al. 2018]In a new study led by Stephanie Olson (UC Riverside and NASA Astrobiology Institute Alternative Earths and Virtual Planetary Laboratory Teams), a team of scientists has proposed an alternative approach: to search for distinctive variability of exoplanet atmospheres that indicates the presence of life.Seasons and Lifeif youre like me, you probably havent spent a lot of time thinking about interactions between the Earths biosphere and its axial tilt. Nonetheless, this interplay is responsible for detectable and distinctive seasonal changes in our planets atmosphere!This schematic shows how oxygen and carbon dioxide levels in the atmosphere vary in opposing phase seasonally, with the increased sunlight in summer driving greater conversion of carbon dioxide into oxygen. [Olson et al. 2018]Since so much of our globe is covered by photosynthesizing life, the seasonal availability of sunlight regulates the conversion of carbon dioxide to oxygen, providing a signature in our atmosphere that varies over the course of the year. And photosynthesis isnt the only culprit! Other biological products evolve seasonally as well as the surface temperature on our globe

Longitudinal analysis of immune abnormalities in varying severities of Chronic Fatigue Syndrome/Myalgic Encephalomyelitis patients.

PubMed

Hardcastle, Sharni Lee; Brenu, Ekua Weba; Johnston, Samantha; Nguyen, Thao; Huth, Teilah; Ramos, Sandra; Staines, Donald; Marshall-Gradisnik, Sonya

2015-09-14

Research has identified immunological abnormalities in Chronic Fatigue Syndrome/Myalgic Encephalomyelitis (CFS/ME), a heterogeneous illness with an unknown cause and absence of diagnostic test. There have been no CFS/ME studies examining innate and adaptive immune cells longitudinally in patients with varying severities. This is the first study to investigate immune cells over 6 months while also examining CFS/ME patients of varying symptom severity. Participants were grouped into 18 healthy controls, 12 moderate and 12 severe CFS/ME patients and flow cytometry was used to examine cell parameters at 0 and 6 months. Over time, iNKT CD62L expression significantly increased in moderate CFS/ME patients and CD56(bright) NK receptors differed in severe CFS/ME. Naïve CD8(+)T cells, CD8(-)CD4(-) and CD56(-)CD16(-) iNKT phenotypes, γδ2T cells and effector memory subsets were significantly increased in severe CFS/ME patients at 6 months. Severe CFS/ME patients were significantly reduced in CD56(bright)CD16(dim) NKG2D, CD56(dim)CD16(-) KIR2DL2/DL3, CD94(-)CD11a(-) γδ1T cells and CD62L(+)CD11a(-) γδ1T cells at 6 months. Severe CFS/ME patients differed from controls and moderate CFS/ME patients over time and expressed significant alterations in iNKT cell phenotypes, CD8(+)T cell markers, NK cell receptors and γδT cells at 6 months. This highlights the importance of further assessing these potential immune biomarkers longitudinally in both moderate and severe CFS/ME patients.

Solute Concentration at a Pumping Well in Non-Gaussian Random Aquifers under Time-Varying Operational Schedules

NASA Astrophysics Data System (ADS)

Libera, A.; de Barros, F.; Riva, M.; Guadagnini, A.

2016-12-01

Managing contaminated groundwater systems is an arduous task for multiple reasons. First, subsurface hydraulic properties are heterogeneous and the high costs associated with site characterization leads to data scarcity (therefore, model predictions are uncertain). Second, it is common for water agencies to schedule groundwater extraction through a temporal sequence of pumping rates to maximize the benefits to anthropogenic activities and minimize the environmental footprint of the withdrawal operations. The temporal variability in pumping rates and aquifer heterogeneity affect dilution rates of contaminant plumes and chemical concentration breakthrough curves (BTCs) at the well. While contaminant transport under steady-state pumping is widely studied, the manner in which a given time-varying pumping schedule affects contaminant plume behavior is tackled only marginally. At the same time, most studies focus on the impact of Gaussian random hydraulic conductivity (K) fields on transport. Here, we systematically analyze the significance of the random space function (RSF) model characterizing K in the presence of distinct pumping operations on the uncertainty of the concentration BTC at the operating well. We juxtapose Monte Carlo based numerical results associated with two models: (a) a recently proposed Generalized Sub-Gaussian model which allows capturing non-Gaussian statistical scaling features of RSFs such as hydraulic conductivity, and (b) the commonly used Gaussian field approximation. Our novel results include an appraisal of the coupled effect of (a) the model employed to depict the random spatial variability of K and (b) transient flow regime, as induced by a temporally varying pumping schedule, on the concentration BTC at the operating well. We systematically quantify the sensitivity of the uncertainty in the contaminant BTC to the RSF model adopted for K (non-Gaussian or Gaussian) in the presence of diverse well pumping schedules. Results contribute to

Chemical composition and antioxidant activities of essential oils and methanol extracts of three wild Lavandula L. species.

PubMed

Messaoud, C; Chograni, H; Boussaid, M

2012-11-01

A comparative study of essential oil composition, polyphenol content and antioxidant activities of Lavandula coronopifolia, Lavandula multifida and Lavandula stoechas subsp. stoechas were reported. Qualitative and quantitative variations in the composition of oils according to species were shown. Lavandula coronopifolia's oil was characterised by high proportions of trans-β-ocimene (26.9%), carvacrol (18.5%), β-bisabolene (13.1%) and myrcene (7.5%). The main components of L. multifida oil are carvacrol (65.1%) and β-bisabolene (24.7%). Lavandula stoechas oil is rich in fenchone (34.3%) and comphor (27.4%). The total phenolic and flavonoid contents also significantly varied among species. Lavandula coronopifolia exhibits the highest phenolic and flavonoid contents (31.3 mg GAE g(-1) and 16.3 mg RE g(-1), respectively), followed by L. multifida (30.8 mg GAE g(-1) and 12.3 mg RE g(-1)). Methanolic extracts and essential oils displayed significant antioxidant activities. The level of antioxidant capacity varied according to extracts and species.

Motor skills under varied gravitoinertial force in parabolic flight

NASA Astrophysics Data System (ADS)

Ross, Helen E.

Parabolic flight produces brief alternating periods of high and low gravitoinertial force. Subjects were tested on various paper-and-pencil aiming and tapping tasks during both normal and varied gravity in flight. It was found that changes in g level caused directional errors in the z body axis (the gravity axis), the arm aiming too high under 0g and too low under 2g. The standard deviation also increased for both vertical and lateral movements in the mid-frontal plane. Both variable and directional errors were greater under 0g than 2g. In an unpaced reciprocal tapping task subjects tended to increase their error rate rather than their movement time, but showed a non-significant trend towards slower speeds under 0g for all movement orientations. Larger variable errors or slower speeds were probably due to the difficulty of re-organising a motor skill in an unfamiliar force environment, combined with anchorage difficulties under 0g.

Relaxation Assessment with Varied Structured Milieu (RELAX).

ERIC Educational Resources Information Center

Cassel, Russell N.; Cassel, Susie L.

1983-01-01

Describes Relaxation Assessment with Varied Structured Milieu (RELAX), a clinical program designed to assess the degree to which an individual is able to demonstrate self-control for overall general relaxation. The program is designed for use with the Cassel Biosensors biofeedback equipment. (JAC)

Fast and slow active control of combustion instabilities in liquid-fueled combustors

NASA Astrophysics Data System (ADS)

Lee, Jae-Yeon

This thesis describes an experimental investigation of two different novel active control approaches that are employed to suppress combustion instabilities in liquid-fueled combustors. A "fast" active controller requires continuous modulation of the fuel injection rate at the frequency of the instability with proper phase and gain. Use of developed optical tools reveals that the "fast" active control system suppresses the instability by changing the nearly flat distribution of the phase between pressure and heat release oscillations to a gradually varying phase distribution, thus dividing the combustion zone into regions that alternately damp and drive combustor oscillations. The effects of these driving/damping regions tend to counter one another, which result in significant damping of the unstable oscillations. In contrast, a "slow" active controller operates at a rate commensurate with that at which operating conditions change during combustor operation. Consequently, "slow" controllers need infrequent activation in response to changes in engine operating conditions to assure stable operation at all times. Using two types of fuel injectors that can produce large controllable variation of fuel spray properties, it is shown that by changing the spray characteristics it is possible to significantly damp combustion instabilities. Similar to the aforementioned result of the "fast" active control study, "slow" change of the fuel spray properties also modifies the nearly flat phase distribution during unstable operation to a gradually varying phase distribution, resulting in combustor "stabilization". Furthermore, deconvolutions of CH*-chemiluminescence images reveal the presence of vortex-flame interaction during unstable operation. Strong driving of instabilities occurs where the mean axial velocity of the flow is approximately zero, a short distance downstream of the flame holder where a significant fraction of the fuel burns in phase with the pressure oscillations

Cognitive behavior and sensory function were significantly influenced by restoration of active ovarian function in postreproductive mice.

PubMed

Parkinson, Kate C; Peterson, Rhett L; Mason, Jeffrey B

2017-06-01

In mammals, the relationship between reproductive function and health has been particularly difficult to define. Previously, in old, postreproductive-aged mice, replacement of senescent ovaries with new ovaries from young, actively cycling mice increased life span. We hypothesized that the same factors that increased life span would also influence health span. In the current experiments, we tested two of the seven domains of function/health, sensory function and cognition to determine if exposure of postreproductive female mice to young transplanted ovaries influenced health span. We evaluated control female CBA/J mice at six, 13 and 16months of age. Additional mice received new (60d) ovaries at 12 or 17months of age and were subsequently evaluated at 16 or 25months of age, respectively. Evaluation of sensory function included two measures of olfactory perception; olfactory identification (buried pellet test) and olfactory discrimination (novel recognition block test). We found a significant age-related decline in olfactory identification in 16-month old mice. This decline was avoided by ovarian transplantation at 12months of age. The olfactory discrimination block test revealed an age-associated increase in time spent on both the novel and familiar blocks. This trend was reversed in 16-month old new-ovary recipients. We evaluated cognitive behavior with a burrowing behavior test. We detected a significant age-related decrease in burrowing behavior at 16months of age. This age-related decrease in burrowing behavior was prevented by ovarian transplantation at 12months of age. In summary, we have shown that cognitive behavior and sensory function, which are negatively influenced by aging, can be positively influenced or restored by re-establishment of active ovarian function in aged female mice. These findings provide strong incentive for further investigation of the positive influence of young ovaries on restoration of health in postreproductive females. Copyright �

Political activism and mental health among Black and Latinx college students.

PubMed

Hope, Elan C; Velez, Gabriel; Offidani-Bertrand, Carly; Keels, Micere; Durkee, Myles I

2018-01-01

The current study investigates the utility of political activism as a protective factor against experiences of racial/ethnic (R/E) discrimination that negatively affect stress, anxiety, and depressive symptoms among Black and Latinx college freshmen at predominately White institutions. Data come from the Minority College Cohort Study, a longitudinal investigation of Black and Latinx college students (N = 504; 44% Black). We conducted multiple regression analyses for each mental health indicator and tested for interaction effects. For Black and Latinx students, the relationship between R/E microaggressions and end of freshman year stress varied by political activism. For Black students, the relationship between R/E microaggressions and end of the year anxiety varied by political activism. There was a significant interaction effect for depressive symptoms among Latinx students. Political activism serves as a protective factor to mitigate the negative effect of R/E discrimination on stress and depressive symptoms for Latinx students. For Black students, higher levels of political activism may exacerbate experiences of R/E microaggressions and relate to more stress and anxiety compared with Black students who are less politically involved. Findings point to the need for a deeper understanding of phenomenological variation in experiences of microaggressions among R/E minorities and how students leverage political activism as an adaptive coping strategy to mitigate race-related stress during college. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Assessing the significance of health information seeking in chronic condition management.

PubMed

Dean, Caress A; Geneus, Christian J; Rice, Shahida; Johns, Marquisha; Quasie-Woode, Delores; Broom, Kevin; Elder, Keith

2017-08-01

To examine the relationship between health information seeking and confidence in performing self-management activities, and to assess the influence of predisposing, enabling, and perceive need factors on confidence to perform self-management activities among adults with chronic conditions. The sample included 6724 adults from the 2007 Health Tracking Household Survey who were ≥18 years with a chronic condition. Binary logistic regression examined the relationship between health information seeking, predisposing, enabling, and perceive need factors and confidence in performing three self-management activities; prevent symptoms, tell doctor concerns, and know when to get medical care. Analyses indicated that 63.7% of adults sought health information. Rural residents who sought health information had 50% (95% CI: 0.28-0.89) lower odds of being confident to tell doctor concerns compared to urban residents who did not seek health information. The relationship between health information seeking and confidence to perform self-management varies by self-management activity. Rurality, education level, having a usual source of care, and perceived health status strongly predict confidence to perform self-management activities. Self-management strategies should incorporate health information seeking behavior that will enhance confidence to perform specific self-management activities, and should incorporate predisposing, enabling, and perceive need factors. Copyright © 2017 Elsevier B.V. All rights reserved.

Parasitic modulation of electromagnetic signals caused by time-varying plasma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Min, E-mail: merovingia1911@126.com; Li, Xiaoping; Xie, Kai

2015-02-15

An experiment on the propagation of electromagnetic (EM) signals in continuous time-varying plasma is described. The time-varying characteristics of plasma are considered to cause a parasitic modulation in both amplitude and phase, and the strength of this modulation, which carries the information of the electron density profile, is closely related to the plasma frequency and the incident wave frequency. Through theoretical analysis, we give an explanation and mechanism of the interaction between the continuous time-varying plasma and EM waves, which is verified by a comparative analysis with experiments performed under the same conditions. The effects of this modulation on themore » EM signals in the plasma sheath cannot be ignored.« less

Quantifying the effect of varying GHG's concentration in Regional Climate Models

NASA Astrophysics Data System (ADS)

López-Romero, Jose Maria; Jerez, Sonia; Palacios-Peña, Laura; José Gómez-Navarro, Juan; Jiménez-Guerrero, Pedro; Montavez, Juan Pedro

2017-04-01

Regional Climate Models (RCMs) are driven at the boundaries by Global Circulation Models (GCM), and in the particular case of Climate Change projections, such simulations are forced by varying greenhouse gases (GHGs) concentrations. In hindcast simulations driven by reanalysis products, the climate change signal is usually introduced in the assimilation process as well. An interesting question arising in this context is whether GHGs concentrations have to be varied within the RCMs model itself, or rather they should be kept constant. Some groups keep the GHGs concentrations constant under the assumption that information about climate change signal is given throughout the boundaries; sometimes certain radiation parameterization schemes do not permit such changes. Other approaches vary these concentrations arguing that this preserves the physical coherence respect to the driving conditions for the RCM. This work aims to shed light on this topic. For this task, various regional climate simulations with the WRF model for the 1954-2004 period have been carried out for using a Euro-CORDEX compliant domain. A series of simulations with constant and variable GHGs have been performed using both, a GCM (ECHAM6-OM) and a reanalysis product (ERA-20C) data. Results indicate that there exist noticeable differences when introducing varying GHGs concentrations within the RCM domain. The differences in 2-m temperature series between the experiments with varying or constant GHGs concentration strongly depend on the atmospheric conditions, appearing a strong interannual variability. This suggests that short-term experiments are not recommended if the aim is to assess the role of varying GHGs. In addition, and consistently in both GCM and reanalysis-driven experiments, the magnitude of temperature trends, as well as the spatial pattern represented by varying GHGs experiment, are closer to the driving dataset than in experiments keeping constant the GHGs concentration. These results

Herbaceous Forage and Selection Patterns by Ungulates across Varying Herbivore Assemblages in a South African Savanna

PubMed Central

Treydte, Anna Christina; Baumgartner, Sabine; Heitkönig, Ignas M. A.; Grant, Catharina C.; Getz, Wayne M.

2013-01-01

Herbivores generally have strong structural and compositional effects on vegetation, which in turn determines the plant forage species available. We investigated how selected large mammalian herbivore assemblages use and alter herbaceous vegetation structure and composition in a southern African savanna in and adjacent to the Kruger National Park, South Africa. We compared mixed and mono-specific herbivore assemblages of varying density and investigated similarities in vegetation patterns under wildlife and livestock herbivory. Grass species composition differed significantly, standing biomass and grass height were almost twice as high at sites of low density compared to high density mixed wildlife species. Selection of various grass species by herbivores was positively correlated with greenness, nutrient content and palatability. Nutrient-rich Urochloa mosambicensis Hack. and Panicum maximum Jacq. grasses were preferred forage species, which significantly differed in abundance across sites of varying grazing pressure. Green grasses growing beneath trees were grazed more frequently than dry grasses growing in the open. Our results indicate that grazing herbivores appear to base their grass species preferences on nutrient content cues and that a characteristic grass species abundance and herb layer structure can be matched with mammalian herbivory types. PMID:24358228

The Bahasa Melayu version of the Global Physical Activity Questionnaire: reliability and validity study in Malaysia.

PubMed

Soo, K L; Wan Abdul Manan, W M; Wan Suriati, W N

2015-03-01

This study aimed to assess the reliability and concurrent validity of the Bahasa Melayu version of the Global Physical Activity Questionnaire (GPAQ-M) by comparing it with the short form of the International Physical Activity Questionnaire (IPAQ-S) and objectively measuring physical activity using a Yamax DigiWalker (Yamax, Tokyo, Japan) pedometer. A total of 100 adults aged between 20 and 58 years from Kelantan in Malaysia voluntarily participated in this study. The Wilcoxon signed-rank analysis showed no significant differences in 2-week test-retest scores for total metabolic equivalent∙minutes∙per week and 4 domains of the GPAQ-M. There was a low but significant relationship between time spent on total physical activity measured by the GPAQ-M and average steps per day recorded using the pedometer (r s = .265, P = .013). Significant correlations were also found between GPAQ-M and the IPAQ-S for varying levels of intensity during physical activities (r s = .309-.466, P < .01). © 2012 APJPH.

Decoding emotional valence from electroencephalographic rhythmic activity.

PubMed

Celikkanat, Hande; Moriya, Hiroki; Ogawa, Takeshi; Kauppi, Jukka-Pekka; Kawanabe, Motoaki; Hyvarinen, Aapo

2017-07-01

We attempt to decode emotional valence from electroencephalographic rhythmic activity in a naturalistic setting. We employ a data-driven method developed in a previous study, Spectral Linear Discriminant Analysis, to discover the relationships between the classification task and independent neuronal sources, optimally utilizing multiple frequency bands. A detailed investigation of the classifier provides insight into the neuronal sources related with emotional valence, and the individual differences of the subjects in processing emotions. Our findings show: (1) sources whose locations are similar across subjects are consistently involved in emotional responses, with the involvement of parietal sources being especially significant, and (2) even though the locations of the involved neuronal sources are consistent, subjects can display highly varying degrees of valence-related EEG activity in the sources.

ICASE/LaRC Symposium on Visualizing Time-Varying Data

NASA Technical Reports Server (NTRS)

Banks, D. C. (Editor); Crockett, T. W. (Editor); Stacy, K. (Editor)

1996-01-01

Time-varying datasets present difficult problems for both analysis and visualization. For example, the data may be terabytes in size, distributed across mass storage systems at several sites, with time scales ranging from femtoseconds to eons. In response to these challenges, ICASE and NASA Langley Research Center, in cooperation with ACM SIGGRAPH, organized the first symposium on visualizing time-varying data. The purpose was to bring the producers of time-varying data together with visualization specialists to assess open issues in the field, present new solutions, and encourage collaborative problem-solving. These proceedings contain the peer-reviewed papers which were presented at the symposium. They cover a broad range of topics, from methods for modeling and compressing data to systems for visualizing CFD simulations and World Wide Web traffic. Because the subject matter is inherently dynamic, a paper proceedings cannot adequately convey all aspects of the work. The accompanying video proceedings provide additional context for several of the papers.

Enzymatic activity of a mine soil varies according to vegetation cover and level of compost applied.

PubMed

de Varennes, Amerilis; Abreu, Maria Manuela; Qu, Guiwei; Cunha-Queda, Cristina

2010-01-01

We applied three doses of compost from mixed municipal solid waste (0, 15, and 30 g kg(-1) of soil) to a soil developed on pyrite mine wastes. Part of the soil was planted with young Erica australis L. collected at the mine; part was fertilized with N-P-K-Mg and sown with Dactylis glomerata L .Bare soil without mineral fertilization was included in the experiment, as well. Compost application to bare soil increased pH, provided plant nutrients, and enhanced the activity of the six soil enzymes tested. Growth of D. glomerata, and E. australis was stimulated in compost-amended soil compared with unamended controls. The presence of D. glomerata led to the greatest activities of soil acid phosphatase, beta-glucosidase, and cellulase compared with bare soil or with soil with E. australis. The presence of E. australis increased the activities of protease and cellulase in amended soil, compared with control, but it impaired dehydrogenase, fl-glucosidase, and acid phosphatase activities. These negative impacts probably derived from phenolic compounds known to be released from roots of this species. The survival strategy of this species seems to include a small need for P in the shoots, and the release of exudates that impair microbial activity and P cycling.

Method of varying a physical property of a material through its depth

DOEpatents

Daniel, Claus

2015-04-21

A method is disclosed for varying a mechanical property of a material at two depths. The method involves the application of at least two laser pulses of different durations. The method involves a determination of the density of the material from the surface to each depth, a determination of the heat capacity of the material from the surface to each depth, and a determination of the thermal conductivity of the material from the surface to each depth. Each laser pulse may affect the density, heat capacity, and thermal conductivity of the material, so it may be necessary to re-evaluate those parameters after each laser pulse and prior to the next pulse. The method may be applied to implantation materials to improve osteoblast and osteoclast activity.

Theory of Turing Patterns on Time Varying Networks.

PubMed

Petit, Julien; Lauwens, Ben; Fanelli, Duccio; Carletti, Timoteo

2017-10-06

The process of pattern formation for a multispecies model anchored on a time varying network is studied. A nonhomogeneous perturbation superposed to an homogeneous stable fixed point can be amplified following the Turing mechanism of instability, solely instigated by the network dynamics. By properly tuning the frequency of the imposed network evolution, one can make the examined system behave as its averaged counterpart, over a finite time window. This is the key observation to derive a closed analytical prediction for the onset of the instability in the time dependent framework. Continuously and piecewise constant periodic time varying networks are analyzed, setting the framework for the proposed approach. The extension to nonperiodic settings is also discussed.

The freedom to explore: examining the influence of independent mobility on weekday, weekend and after-school physical activity behaviour in children living in urban and inner-suburban neighbourhoods of varying socioeconomic status.

PubMed

Stone, Michelle R; Faulkner, Guy Ej; Mitra, Raktim; Buliung, Ron N

2014-01-22

Children's independent mobility (CIM) is critical to healthy development in childhood. The physical layout and social characteristics of neighbourhoods can impact opportunities for CIM. While global evidence is mounting on CIM, to the authors' knowledge, Canadian data on CIM and related health outcomes (i.e., physical activity (PA) behaviour) are missing. The purpose of this study was to examine if CIM is related to multiple characteristics of accelerometry-measured PA behaviour (total PA, light PA, moderate-to-vigorous PA, time spent sedentary) and whether associations between CIM and PA behaviour systematically vary by place of residence, stratifying by gender and type of day/period (weekdays, after-school, weekend). Participants were recruited through Project BEAT (Built Environment and Active Transport; http://www.beat.utoronto.ca). Children (n = 856) were stratified into four neighbourhood classifications based on the period of neighbourhood development (urban built environment (BE) (old BE) versus inner-suburban BE (new BE)) and socioeconomic status (SES; low SES and high SES). Physical activity was measured via accelerometry (ActiGraph GT1M). CIM was assessed via parental report and two categories were created (low CIM, n = 332; high CIM, n = 524). A series of two-factor ANOVAs were used to determine gender-specific differences in PA for weekdays, weekend days and the after-school period, according to level of CIM, across four neighbourhood classifications. Children who were granted at least some independent mobility (high CIM) had more positive PA profiles across the school week, during the after-school period, and over the weekend; they were also less sedentary. The influence of CIM on PA behaviour was particularly salient during the after-school period. Associations of CIM with PA varied by gender, and also by neighbourhood classification. CIM seemed to matter more in urban neighbourhoods for boys and suburban neighbourhoods for girls. Our

Nestin-Cre Mice Are Affected by Hypopituitarism, Which Is Not Due to Significant Activity of the Transgene in the Pituitary Gland

PubMed Central

Galichet, Christophe; Lovell-Badge, Robin; Rizzoti, Karine

2010-01-01

Nestin-Cre mice express Cre recombinase under control of the rat nestin promoter and central nervous system (CNS) enhancer. While endogenous Nestin is expressed in some other tissues including the pituitary gland, Nestin-Cre mice induce recombination predominantly in the CNS. For this reason, they have been widely used to explore gene function or cell fate in the latter. Pituitary hormonal deficiencies, or hypopituitarism, are associated with a wide range of symptoms and with a significant morbidity. These can have a neural and/or a pituitary origin as the gland's secretions are controlled by the hypothalamus. We report here that Nestin-Cre mice themselves are affected by mild hypopituitarism. Hence, physiological consequences are expected, especially in combination with defects resulting from Cre mediated deletion of any gene under investigation. To further investigate the origin of this phenotype, we re-examined the activity of the transgene. We compared it with expression of Nestin itself in the context of the hypothalamo-pituitary axis, especially in the light of a recent report showing pituitary Nestin-Cre activity, which contrasts with previous data. Our results disagree with those of this recent study and do not support the claim that Nestin positive cells are present in the pituitary anlagen, the Rathke's pouch (RP). Moreover we did not observe any significant activity in the post-natal pituitary, in agreement with the initial report. PMID:20625432

RPA-mediated unfolding of systematically varying G-quadruplex structures.

PubMed

Ray, Sujay; Qureshi, Mohammad H; Malcolm, Dominic W; Budhathoki, Jagat B; Celik, Uğur; Balci, Hamza

2013-05-21

G-quadruplex (GQ) is a noncanonical nucleic acid structure that is formed by guanine rich sequences. Unless it is destabilized by proteins such as replication protein A (RPA), GQ could interfere with DNA metabolic functions, such as replication or repair. We studied RPA-mediated GQ unfolding using single-molecule FRET on two groups of GQ structures that have different loop lengths and different numbers of G-tetrad layers. We observed a linear increase in the steady-state stability of the GQ against RPA-mediated unfolding with increasing number of layers or decreasing loop length. The stability demonstrated by different GQ structures varied by at least three orders of magnitude. Those with shorter loops (less than three nucleotides long) or a greater number of layers (more than three layers) maintained a significant folded population even at physiological RPA concentration (≈1 μM), raising the possibility of physiological viability of such GQ structures. Finally, we measured the transition time between the start and end of the RPA-mediated GQ unfolding process to be 0.35 ± 0.10 s for all GQ constructs we studied, despite significant differences in their steady-state stabilities. We propose a two-step RPA-mediated GQ unfolding mechanism that is consistent with our observations. Copyright © 2013 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Physical activity and neuropsychiatric symptoms of Parkinson disease.

PubMed

Abrantes, Ana M; Friedman, Joseph H; Brown, Richard A; Strong, David R; Desaulniers, Julie; Ing, Eileen; Saritelli, Jennifer; Riebe, Deborah