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\"The Rise of the American Security State is about the militarization of U.S. foreign policy starting about midway through the twentieth century, increasing during the Cold War era and, somewhat surprisingly, continuing in the post-Cold War period\"-- Provided by publisher.

We describe refinements in optogenetic methods for circuit mapping that enable measurements of functional synaptic connectivity with single-neuron resolution. By expanding a two-photon beam in the imaging plane using the temporal focusing method and restricting channelrhodopsin to the soma and proximal dendrites, we are able to reliably evoke action potentials in individual neurons, verify spike generation with GCaMP6s, and determine the presence or absence of synaptic connections with patch-clamp electrophysiological recording. Nerve cells called neurons carry information around the body in the form of electrical impulses and pass signals to each another to form circuits that link different organs and tissues. Mapping out the neurons in the brain can reveal how different circuits contribute to an animal’s behavior. Yet, because the brains of mammals contain millions of neurons, these circuits are often difficult to untangle. One way to tease apart circuits of neurons uses a technique called optogenetics, which involves manipulating the genes inside neurons such that the cells produce a light-sensitive protein and respond to blasts of light. The aim is to activate a specific neuron and then see which other neurons are activated shortly afterwards, revealing a connected circuit. However, exposure to light can be imprecise. Also, the neurons in the brain are so densely packed that the nerve endings from neighboring neurons often overlap without actually being connected. This makes it unclear if activated neurons are truly part of the same circuit or simply bystanders reacting to the same nearby blast of light. To overcome this limitation, Baker et al. developed a new optogenetic approach with two important features. First, the approach makes use of a light-sensitive protein called channelrhodopsin that had been modified to confine it to the cell body of each neuron and exclude it from the nerve endings. Second, pulses of laser light were specifically shaped to target only the cell body of an individual neuron. Baker et al. show that this new method can activate neurons inside slices of mouse brain without affecting the neighboring neurons. This allowed circuits of neurons to be mapped in fine detail. This new optogenetic method is expected to shed light on the patterns of nerve signals that contribute to animal behavior. The approach may also be modified to use other light-sensitive proteins or investigate how neural circuits are altered in animal models of human disorders like autism and schizophrenia.

Deformations of sandy soils around geotechnical structures generally involve strains in the range small (0·01%) to medium (0·5%). In this strain range the soil exhibits non-linear stress–strain behaviour, which should be incorporated in any deformation analysis. In order to capture the possible variability in the non-linear behaviour of various sands, a database was constructed including the secant shear modulus degradation curves of 454 tests from the literature. By obtaining a unique S-shaped curve of shear modulus degradation, a modified hyperbolic relationship was fitted. The three curve-fitting parameters are: an elastic threshold strain γ e , up to which the elastic shear modulus is effectively constant at G 0 ; a reference strain γ r , defined as the shear strain at which the secant modulus has reduced to 0·5G 0 ; and a curvature parameter a, which controls the rate of modulus reduction. The two characteristic strains γ e and γ r were found to vary with sand type (i.e. uniformity coefficient), soil state (i.e. void ratio, relative density) and mean effective stress. The new empirical expression for shear modulus reduction G/G 0 is shown to make predictions that are accurate within a factor of 1·13 for one standard deviation of random error, as determined from 3860 data points. The initial elastic shear modulus, G 0 , should always be measured if possible, but a new empirical relation is shown to provide estimates within a factor of 1·6 for one standard deviation of random error, as determined from 379 tests. The new expressions for non-linear deformation are easy to apply in practice, and should be useful in the analysis of geotechnical structures under static loading.

The signals in cerebellar Purkinje cells sufficient to instruct motor learning have not been systematically determined. Therefore, we applied optogenetics in mice to autonomously excite Purkinje cells and measured the effect of this activity on plasticity induction and adaptive behavior. Ex vivo, excitation of channelrhodopsin-2-expressing Purkinje cells elicits dendritic Ca 2+ transients with high-intensity stimuli initiating dendritic spiking that additionally contributes to the Ca 2+ response. Channelrhodopsin-2-evoked Ca 2+ transients potentiate co-active parallel fiber synapses; depression occurs when Ca 2+ responses were enhanced by dendritic spiking. In vivo, optogenetic Purkinje cell activation drives an adaptive decrease in vestibulo-ocular reflex gain when vestibular stimuli are paired with relatively small-magnitude Purkinje cell Ca 2+ responses. In contrast, pairing with large-magnitude Ca 2+ responses increases vestibulo-ocular reflex gain. Optogenetically induced plasticity and motor adaptation are dependent on endocannabinoid signaling, indicating engagement of this pathway downstream of Purkinje cell Ca 2+ elevation. Our results establish a causal relationship among Purkinje cell Ca 2+ signal size, opposite-polarity plasticity induction, and bidirectional motor learning. Plastic reweighting of parallel fiber synaptic strength is a mechanism for the acquisition of cerebellum-dependent motor learning. Here, the authors found that optogenetic activation of PCs generates dendritic Ca2+ signals that induce plasticity in vitro and instruct learned changes to coincident eye movements in vivo.

Particle acceleration and loss in the million electron Volt (MeV) energy range (and above) is the least understood aspect of radiation belt science. In order to measure cleanly and separately both the energetic electron and energetic proton components, there is a need for a carefully designed detector system. The Relativistic Electron-Proton Telescope (REPT) on board the Radiation Belt Storm Probe (RBSP) pair of spacecraft consists of a stack of high-performance silicon solid-state detectors in a telescope configuration, a collimation aperture, and a thick case surrounding the detector stack to shield the sensors from penetrating radiation and bremsstrahlung. The instrument points perpendicular to the spin axis of the spacecraft and measures high-energy electrons (up to ∼20 MeV) with excellent sensitivity and also measures magnetospheric and solar protons to energies well above E =100 MeV. The instrument has a large geometric factor ( g =0.2 cm 2  sr) to get reasonable count rates (above background) at the higher energies and yet will not saturate at the lower energy ranges. There must be fast enough electronics to avert undue dead-time limitations and chance coincidence effects. The key goal for the REPT design is to measure the directional electron intensities (in the range 10 −2 –10 6 particles/cm 2  s sr MeV) and energy spectra (Δ E / E ∼25 %) throughout the slot and outer radiation belt region. Present simulations and detailed laboratory calibrations show that an excellent design has been attained for the RBSP needs. We describe the engineering design, operational approaches, science objectives, and planned data products for REPT.

Abstract Background Psychiatric comorbidity in inflammatory bowel disease (IBD) is well known; however, data from a truly representative sample are sparse. We aimed to estimate the incidence and prevalence of psychiatric disorders in an IBD cohort compared with a matched cohort without IBD. Methods Using population-based administrative health data from Manitoba, Canada, we identified all persons with incident IBD from 1989 to 2012 and a general population matched cohort (5:1). We applied validated algorithms for IBD, depression, anxiety disorders, bipolar disorder, and schizophrenia to determine the annual incidence of these conditions post-IBD diagnosis and their lifetime and current prevalence. Results There were 6119 incident cases of IBD and 30,573 matched individuals. After adjustment for age, sex, socioeconomic status, region of residence, and year, there was a higher incidence in the IBD cohort compared with controls for depression (incidence rate ratio [IRR], 1.58; 95% confidence interval [CI], 1.41-1.76), anxiety disorder (IRR, 1.39; 95% CI, 1.26-1.53), bipolar disorder (IRR, 1.82; 95% CI, 1.44-2.30), and schizophrenia (IRR, 1.64; 95% CI, 0.95-2.84). Incidence rate ratios were similar for Crohn's disease and ulcerative colitis between males and females and were stable over time. However, within the IBD cohort, the incidence rates of depression, anxiety, and bipolar disorders were higher among females, those aged 18-24 years vs those older than 44 years, urbanites, and those of lower socioeconomic status. The lifetime and current prevalence rates of psychiatric disorders were also higher in the IBD than the matched cohort. Conclusions The incidence and prevalence of psychiatric disorders are elevated in the IBD population.

The Radiation Belt Storm Probes (RBSP)-Energetic Particle, Composition, and Thermal Plasma (ECT) suite contains an innovative complement of particle instruments to ensure the highest quality measurements ever made in the inner magnetosphere and radiation belts. The coordinated RBSP-ECT particle measurements, analyzed in combination with fields and waves observations and state-of-the-art theory and modeling, are necessary for understanding the acceleration, global distribution, and variability of radiation belt electrons and ions, key science objectives of NASA’s Living With a Star program and the Van Allen Probes mission. The RBSP-ECT suite consists of three highly-coordinated instruments: the Magnetic Electron Ion Spectrometer (MagEIS), the Helium Oxygen Proton Electron (HOPE) sensor, and the Relativistic Electron Proton Telescope (REPT). Collectively they cover, continuously, the full electron and ion spectra from one eV to 10’s of MeV with sufficient energy resolution, pitch angle coverage and resolution, and with composition measurements in the critical energy range up to 50 keV and also from a few to 50 MeV/nucleon. All three instruments are based on measurement techniques proven in the radiation belts. The instruments use those proven techniques along with innovative new designs, optimized for operation in the most extreme conditions in order to provide unambiguous separation of ions and electrons and clean energy responses even in the presence of extreme penetrating background environments. The design, fabrication and operation of ECT spaceflight instrumentation in the harsh radiation belt environment ensure that particle measurements have the fidelity needed for closure in answering key mission science questions. ECT instrument details are provided in companion papers in this same issue. In this paper, we describe the science objectives of the RBSP-ECT instrument suite on the Van Allen Probe spacecraft within the context of the overall mission objectives, indicate how the characteristics of the instruments satisfy the requirements to achieve these objectives, provide information about science data collection and dissemination, and conclude with a description of some early mission results.

Amygdala plays crucial roles in emotional learning. The lateral amygdala (LA) is the input station of the amygdala, where learning related plasticity occurs. The LA is cortical like in nature in terms of its cellular make up, composed of a majority of principal cells and a minority of interneurons with distinct subtypes defined by morphology, intrinsic electrophysiological properties and neurochemical expression profile. The specific functions served by LA interneuron subtypes remain elusive. This study aimed to elucidate the interneuron subtype mediating feedback inhibition. Electrophysiological evidence involving antidromic activation of recurrent LA circuitry via basolateral amygdala stimulation and paired recordings implicate low-threshold spiking interneurons in feedback inhibition. Recordings in somatostatin-cre animals crossed with tdtomato mice have revealed remarkable similarities between a subset of SOM+ interneurons and LTS interneurons. This study concludes that LTS interneurons, most of which are putatively SOM+, mediate feedback inhibition in the LA. Parallels with cortical areas and potential implications for information processing and plasticity are discussed.

NASA's Solar Probe Plus (SPP) mission will make the first in situ measurements of the solar corona and the birthplace of the solar wind. The FIELDS instrument suite on SPP will make direct measurements of electric and magnetic fields, the properties of in situ plasma waves, electron density and temperature profiles, and interplanetary radio emissions, amongst other things. Here, we describe the scientific objectives targeted by the SPP/FIELDS instrument, the instrument design itself, and the instrument concept of operations and planned data products.

The plastic limit of soils was first described by Atterberg in 1911. The thread-rolling test was standardised at the US Public Roads Bureau in the 1920s and 1930s, and has subsequently become one of the standard tests of soil mechanics. This paper reviews the original definitions of plastic limit as proposed by Atterberg, and proposes that the brittle failure observed in the plastic limit test is caused by either air entry or cavitation in the clay. Critical state soil mechanics is used to show that the observed range of undrained shear strengths of soils at plastic limit is consistent with this hypothesis. The fallacy that strength at plastic limit is a constant is highlighted, and the implications for geotechnical practice are discussed.