Influence of the ambient solar wind flow on the propagation behavior of interplanetary CMEs

We study three CME/ICME events (2008 June 1-6, 2009 February 13-18, 2010 April 3-5) tracked from Sun to 1 AU in remote-sensing observations of STEREO Heliospheric Imagers and in situ plasma and magnetic field measurements. We focus on the ICME propagation in IP space that is governed by two forces, the propelling Lorentz force and the drag force. We address the question at which heliospheric distance range the drag becomes dominant and the CME gets adjusted to the solar wind flow. To this aim we analyze speed differences between ICMEs and the ambient solar wind flow as function of distance. The evolution of the ambient solar wind flow is derived from ENLIL 3D MHD model runs using different solar wind models, namely Wang-Sheeley-Arge (WSA) and MHD-Around-A-Sphere (MAS). Comparing the measured CME kinematics with the solar wind models we find that the CME speed gets adjusted to the solar wind speed at very different heliospheric distances in the three events under study: from below 30 Rs, to beyond 1 AU, depending on the CME and ambient solar wind characteristics. ENLIL can be used to derive important information about the overall structure of the background solar wind, providing more reliable results during times of low solar activity than during times of high solar activity. The results from this study enable us to get a better insight into the forces acting on CMEs over the IP space distance range, which is an important prerequisite in order to predict their 1 AU transit times.Comment: accepted for publication in Ap

Use of an animal model in situations of limited subclass numbers and high degrees of relationships

Breeding value estimation procedures for two traits with moderate and high heritability were evaluated by using a single-trait animal model and computer-simulated data designs. Of interest were the effects of differing numbers of animals and degrees of relationships among animals within and across contemporary groups (tests). Test effects were assumed fixed and animal effects were assumed random. Family size, number of families per contemporary group, and degree of genetic relationships within and across contemporary groups were varied to determine interrelationships among the factors. Results were compared on the basis of accuracy by using both the correlation of true and estimated breeding values and the prediction error variance obtained from the inverse of the coefficient matrix of the mixed-model equations. Small contemporary groups in conjunction with evaluation of closely related families caused average accuracy to decrease relative to that obtained with the same number of unrelated animals because genetically related animals were less accurately evaluated relative to one another. Connecting contemporary groups with a genetic relationship matrix formed a large set of interdependent equations and improved the average accuracy of predicted breeding values. The slight decrease in accuracy for genetically related animals was more than offset by the increase in accuracy of evaluation for their unrelated test mates because the proportion of fixed effects to random effects was smaller. Care must be exercised in designing evaluation schemes involving small populations, and the decision of which fixed effects to include in the model is critical

An external quality control survey (EQCS) for serum cortisol

Peer Reviewe

Quantifying anhedonia-like symptoms in marmosets using appetitive Pavlovian conditioning.

Blunted reward responsivity is associated with anhedonia in humans and is a core feature of depression. This protocol describes how to train the common marmoset, Callithrix jacchus, on an appetitive Pavlovian conditioning paradigm to measure behavioral and cardiovascular correlates of anticipatory and consummatory phases of reward processing. We describe how to use intracerebral infusions to manipulate brain regions whose activity is relevant to impaired reward processing in depression and how the paradigm can be used to test antidepressant efficacy. For complete details on the use and execution of this protocol, please refer to Alexander et al. (2019)

Bistable Helmholtz bright solitons in saturable materials

We present, to the best of our knowledge, the first exact analytical solitons of a nonlinear Helmholtz equation with a saturable refractive-index model. These new two-dimensional spatial solitons have a bistable characteristic in some parameter regimes, and they capture oblique (arbitrary-angle) beam propagation in both the forward and backward directions. New conservation laws are reported, and the classic paraxial solution is recovered in an appropriate multiple limit. Analysis and simulations examine the stability of both solution branches, and stationary Helmholtz solitons are found to emerge from a range of perturbed input beams

Multiscale analyses of solar‐induced florescence and gross primary production

Solar‐induced fluorescence (SIF) has shown great promise for probing spatiotemporal variations in terrestrial gross primary production (GPP), the largest component flux of the global carbon cycle. However, scale mismatches between SIF and ground‐based GPP have posed challenges toward fully exploiting these data. We used SIF obtained at high spatial sampling rates and resolution by NASA’s Orbiting Carbon Observatory‐2 satellite to elucidate GPP‐SIF relationships across space and time in the U.S. Corn Belt. Strong linear scaling functions (R2 ≥ 0.79) that were consistent across instantaneous to monthly time scales were obtained for corn ecosystems and for a heterogeneous landscape based on tall tower observations. Although the slope of the corn function was ~56% higher than for the landscape, SIF was similar for corn (C4) and soybean (C3). Taken together, there is strong observational evidence showing robust linear GPP‐SIF scaling that is sensitive to plant physiology but insensitive to the spatial or temporal scale.Key PointsGPP scales linearly with SIF from instantaneous to monthly time scalesAggregating ecosystem GPP‐SIF functions yield a representative landscape relation that matched one obtained directly using tall tower GPPGPP‐SIF relations showed sensitivity to plant physiology but not spatiotemporal scalePeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135999/1/grl55274_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/135999/2/grl55274.pd

Tenure through Tyranny? Repression, Dissent, and Leader Removal in Africa and Latin America, 1990–2006

With few exceptions, prior research on leadership survival focuses largely on state institutional characteristics or economic context. We shift this orientation by explicitly considering the important role contentious interactions between the incumbent regime and dissident actors play in determining the duration of leader tenure as well as the manner in which a leader is removed. Specifically, we focus on the severity of the incumbent leader's response to dissident challenges. We contend that the severity of this response represents a critical signal which informs the decisions of specific audiences that ultimately determine the incumbent's survival. To evaluate our argument, we employ detailed information on dissent–repression dynamics and leader survival for a leader-month sample of 69 African and Latin American states between 1990 and 2006. Our results suggest that incumbents are vulnerable to coup d’ état when government repression is perceived as weaker than would normally be expected for a given challenge. By contrast, removal via revolution becomes increasingly likely when repression dramatically exceeds the levels that would normally be warranted given the extant challenge