Cross-Recurrence Quantification Analysis of Categorical and Continuous Time Series: an R package

This paper describes the R package crqa to perform cross-recurrence quantification analysis of two time series of either a categorical or continuous nature. Streams of behavioral information, from eye movements to linguistic elements, unfold over time. When two people interact, such as in conversation, they often adapt to each other, leading these behavioral levels to exhibit recurrent states. In dialogue, for example, interlocutors adapt to each other by exchanging interactive cues: smiles, nods, gestures, choice of words, and so on. In order for us to capture closely the goings-on of dynamic interaction, and uncover the extent of coupling between two individuals, we need to quantify how much recurrence is taking place at these levels. Methods available in crqa would allow researchers in cognitive science to pose such questions as how much are two people recurrent at some level of analysis, what is the characteristic lag time for one person to maximally match another, or whether one person is leading another. First, we set the theoretical ground to understand the difference between 'correlation' and 'co-visitation' when comparing two time series, using an aggregative or cross-recurrence approach. Then, we describe more formally the principles of cross-recurrence, and show with the current package how to carry out analyses applying them. We end the paper by comparing computational efficiency, and results' consistency, of crqa R package, with the benchmark MATLAB toolbox crptoolbox. We show perfect comparability between the two libraries on both levels

Crop coefficients, growth rates and quality of cool-season turfgrasses

Determination of crop coefficients (Kc), the ratio between actual (ETa) and reference evapotranspiration (ET0), is necessary to schedule irrigation. Our objective was to determine Kc, turf quality and growth rate under daily irrigation to field capacity (FC = −3 kPa tension) and drying. Minilysimeters installed in a green (mowing height 3–5 mm) and fairway (15 mm) were weighed during four periods of 4–10 days duration in 2009 and 2010. Crop coefficients on the second and subsequent days after irrigation were not significantly different among species and averaged 0.81 and 0.91 on green and fairway, respectively. On the first day after irrigation, the Kc varied from 1.67 to 2.85 and decreased in the order Agrostis capillaris > Festuca rubra ssp. litoralis > F. rubra ssp. commutata > A. stolonifera > A. canina on the green, and F. rubra ssp. litoralis > Lolium perenne > F.rubra ssp. rubra > Poa pratensis > F. rubra ssp. commutata on the fairway. Drying reduced the average daily height growth from 0.98 to 0.74 mm on the green and 1.97–1.72 mm on the fairway. Scores for turf quality were reduced but remained acceptable. Although the Kc during the first day after irrigation to FC may be overestimated due to latent soil heat and a possible oasis effect, we conclude that irrigation to FC should be avoided as it causes excessive water use

Interpersonal Synergies

We present the perspective that interpersonal movement coordination results from establishing interpersonal synergies. Interpersonal synergies are higher-order control systems formed by coupling movement system degrees of freedom of two (or more) actors. Characteristic features of synergies identified in studies of intrapersonal coordination – dimensional compression and reciprocal compensation – are revealed in studies of interpersonal coordination that applied the uncontrolled manifold approach and principal component analysis to interpersonal movement tasks. Broader implications of the interpersonal synergy approach for movement science include an expanded notion of mechanism and an emphasis on interaction-dominant dynamics

Upper-Room Ultraviolet Light and Negative Air Ionization to Prevent Tuberculosis Transmission

Background Institutional tuberculosis (TB) transmission is an important public health problem highlighted by the HIV/AIDS pandemic and the emergence of multidrug- and extensively drug-resistant TB. Effective TB infection control measures are urgently needed. We evaluated the efficacy of upper-room ultraviolet (UV) lights and negative air ionization for preventing airborne TB transmission using a guinea pig air-sampling model to measure the TB infectiousness of ward air. Methods and Findings For 535 consecutive days, exhaust air from an HIV-TB ward in Lima, Perú, was passed through three guinea pig air-sampling enclosures each housing approximately 150 guinea pigs, using a 2-d cycle. On UV-off days, ward air passed in parallel through a control animal enclosure and a similar enclosure containing negative ionizers. On UV-on days, UV lights and mixing fans were turned on in the ward, and a third animal enclosure alone received ward air. TB infection in guinea pigs was defined by monthly tuberculin skin tests. All guinea pigs underwent autopsy to test for TB disease, defined by characteristic autopsy changes or by the culture of Mycobacterium tuberculosis from organs. 35% (106/304) of guinea pigs in the control group developed TB infection, and this was reduced to 14% (43/303) by ionizers, and to 9.5% (29/307) by UV lights (both p < 0.0001 compared with the control group). TB disease was confirmed in 8.6% (26/304) of control group animals, and this was reduced to 4.3% (13/303) by ionizers, and to 3.6% (11/307) by UV lights (both p < 0.03 compared with the control group). Time-to-event analysis demonstrated that TB infection was prevented by ionizers (log-rank 27; p < 0.0001) and by UV lights (log-rank 46; p < 0.0001). Time-to-event analysis also demonstrated that TB disease was prevented by ionizers (log-rank 3.7; p = 0.055) and by UV lights (log-rank 5.4; p = 0.02). An alternative analysis using an airborne infection model demonstrated that ionizers prevented 60% of TB infection and 51% of TB disease, and that UV lights prevented 70% of TB infection and 54% of TB disease. In all analysis strategies, UV lights tended to be more protective than ionizers. Conclusions Upper-room UV lights and negative air ionization each prevented most airborne TB transmission detectable by guinea pig air sampling. Provided there is adequate mixing of room air, upper-room UV light is an effective, low-cost intervention for use in TB infection control in high-risk clinical settings

Advancing In Situ Modeling of ICMEs: New Techniques for New Observations

It is generally known that multi-spacecraft observations of interplanetary coronal mass ejections (ICMEs) more clearly reveal their three-dimensional structure than do observations made by a single spacecraft. The launch of the STEREO twin observatories in October 2006 has greatly increased the number of multipoint studies of ICMEs in the literature, but this field is still in its infancy. To date, most studies continue to use on flux rope models that rely on single track observations through a vast, multi-faceted structure, which oversimplifies the problem and often hinders interpretation of the large-scale geometry, especially for cases in which one spacecraft observes a flux rope, while another does not. In order to tackle these complex problems, new modeling techniques are required. We describe these new techniques and analyze two ICMEs observed at the twin STEREO spacecraft on 22-23 May 2007, when the spacecraft were separated by ~8 degrees. We find a combination of non-force-free flux rope multi-spacecraft modeling, together with a new non-flux rope ICME plasma flow deflection model, better constrains the large-scale structure of these ICMEs. We also introduce a new spatial mapping technique that allows us to put multispacecraft observations and the new ICME model results in context with the convecting solar wind. What is distinctly different about this analysis is that it reveals aspects of ICME geometry and dynamics in a far more visually intuitive way than previously accomplished. In the case of the 22-23 May ICMEs, the analysis facilitates a more physical understanding of ICME large-scale structure, the location and geometry of flux rope sub-structures within these ICMEs, and their dynamic interaction with the ambient solar wind

Reply to comment by P. Riley and J. T. Gosling on “Are high‐latitude forward‐reverse shock pairs driven by overexpansion?”

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95455/1/jgra18795.pd

Near-Earth Solar Wind Flows and Related Geomagnetic Activity During more than Four Solar Cycles (1963-2011)

In past studies, we classified the near-Earth solar wind into three basic flow types based on inspection of solar wind plasma and magnetic field parameters in the OMNI database and additional data (e.g., geomagnetic indices, energetic particle, and cosmic ray observations). These flow types are: (1) High-speed streams associated with coronal holes at the Sun, (2) Slow, interstream solar wind, and (3) Transient flows originating with coronal mass ejections at the Sun, including interplanetary coronal mass ejections and the associated upstream shocks and post-shock regions. The solar wind classification in these previous studies commenced with observations in 1972. In the present study, as well as updating this classification to the end of 2011, we have extended the classification back to 1963, the beginning of near-Earth solar wind observations, thereby encompassing the complete solar cycles 20 to 23 and the ascending phase of cycle 24. We discuss the cycle-to-cycle variations in near-Earth solar wind structures and l1e related geomagnetic activity over more than four solar cycles, updating some of the results of our earlier studies

The floor in the interplanetary magnetic field: Estimation on the basis of relative duration of ICME observations in solar wind during 1976-2000

To measure the floor in interplanetary magnetic field and estimate the time- invariant open magnetic flux of Sun, it is necessary to know a part of magnetic field of Sun carried away by CMEs. In contrast with previous papers, we did not use global solar parameters: we identified different large-scale types of solar wind for 1976-2000 interval, obtained a fraction of interplanetary CMEs (ICMEs) and calculated magnitude of interplanetary magnetic field B averaged over 2 Carrington rotations. The floor of magnetic field is estimated as B value at solar cycle minimum when the ICMEs were not observed and it was calculated to be 4,65 \pm 6,0 nT. Obtained value is in a good agreement with previous results.Comment: 10 pages, 2 figures, submitted in GR

Pressure balance at the magnetopause: Experimental studies

The pressure balance at the magnetopause is formed by magnetic field and plasma in the magnetosheath, on one side, and inside the magnetosphere, on the other side. In the approach of dipole earth's magnetic field configuration and gas-dynamics solar wind flowing around the magnetosphere, the pressure balance predicts that the magnetopause distance R depends on solar wind dynamic pressure Pd as a power low R ~ Pd^alpha, where the exponent alpha=-1/6. In the real magnetosphere the magnetic filed is contributed by additional sources: Chapman-Ferraro current system, field-aligned currents, tail current, and storm-time ring current. Net contribution of those sources depends on particular magnetospheric region and varies with solar wind conditions and geomagnetic activity. As a result, the parameters of pressure balance, including power index alpha, depend on both the local position at the magnetopause and geomagnetic activity. In addition, the pressure balance can be affected by a non-linear transfer of the solar wind energy to the magnetosheath, especially for quasi-radial regime of the subsolar bow shock formation proper for the interplanetary magnetic field vector aligned with the solar wind plasma flow.Comment: 8 pages, 2 figure

Potent and Broad Inhibition of HIV-1 by a Peptide from the gp41 Heptad Repeat-2 Domain Conjugated to the CXCR4 Amino Terminus.

HIV-1 entry can be inhibited by soluble peptides from the gp41 heptad repeat-2 (HR2) domain that interfere with formation of the 6-helix bundle during fusion. Inhibition has also been seen when these peptides are conjugated to anchoring molecules and over-expressed on the cell surface. We hypothesized that potent anti-HIV activity could be achieved if a 34 amino acid peptide from HR2 (C34) were brought to the site of virus-cell interactions by conjugation to the amino termini of HIV-1 coreceptors CCR5 or CXCR4. C34-conjugated coreceptors were expressed on the surface of T cell lines and primary CD4 T cells, retained the ability to mediate chemotaxis in response to cognate chemokines, and were highly resistant to HIV-1 utilization for entry. Notably, C34-conjugated CCR5 and CXCR4 each exhibited potent and broad inhibition of HIV-1 isolates from diverse clades irrespective of tropism (i.e., each could inhibit R5, X4 and dual-tropic isolates). This inhibition was highly specific and dependent on positioning of the peptide, as HIV-1 infection was poorly inhibited when C34 was conjugated to the amino terminus of CD4. C34-conjugated coreceptors could also inhibit HIV-1 isolates that were resistant to the soluble HR2 peptide inhibitor, enfuvirtide. When introduced into primary cells, CD4 T cells expressing C34-conjugated coreceptors exhibited physiologic responses to T cell activation while inhibiting diverse HIV-1 isolates, and cells containing C34-conjugated CXCR4 expanded during HIV-1 infection in vitro and in a humanized mouse model. Notably, the C34-conjugated peptide exerted greater HIV-1 inhibition when conjugated to CXCR4 than to CCR5. Thus, antiviral effects of HR2 peptides can be specifically directed to the site of viral entry where they provide potent and broad inhibition of HIV-1. This approach to engineer HIV-1 resistance in functional CD4 T cells may provide a novel cell-based therapeutic for controlling HIV infection in humans