Intersectional Targeting Reveals Heterogeneous Nature of Glp1r- and Lepr expressing POMC Neurons

The anorexigenic pro-opiomelanocortin (Pomc)-expressing neurons of the arcuate nucleus of the hypothalamus (ARC) are constituents of the melanocortin system, and their function is pivotal in control of systemic energy homeostasis. Adjacency to the median eminence and a fenestrated blood-brain barrier exposes the neurons of the melanocortin system to hormones and stimuli from the periphery. These signals are integrated and serve as a basis for the exertion of optimal responses in the regulation of homeostatic processes. Defined by the expression of POMC, it has been assumed that these neurons are a uniform group; however, cumulative electrophysiological and single-cell sequencing evidence hint at both functional and molecular heterogeneity of POMC neurons. Deciphering this heterogeneity is crucial in understanding how a wide range of stimuli are integrated and unraveling the intricacies in metabolic control mediated by different POMC subpopulations. In the present study, we utilize intersectional Cre/Dre-dependent transgenic mouse models to successfully target distinct leptin receptor (Lepr) and glucagon-like peptide receptor (Glp1r) expressing POMC neurons. This system enabled a detailed description of anatomical distribution, translational profiling, and functional characterization of these two POMC subpopulations. Our experiments reveal that POMCLepr+ and POMCGlp1r+ neurons exhibit distinct anatomical distribution patterns within the ARC by using tissue clearing and three-dimensional image assessment. In addition, electrophysiological recordings from these neurons illustrated variations in their key intrinsic properties. Molecular profiling revealed a differential expression in receptors for energy state communicating hormones and neurotransmitters. Finally, employing the Cre/Dre-dependent activatory chemogenetic system for both neuronal groups demonstrated differential regulation of the two subpopulations with regards to food intake. Collectively, this work reveals heterogeneity of critical metabolism-regulatory POMC neurons

Image processing using Gallium Arsenide (GaAs) technology

The need to increase the information return from space-borne imaging systems has increased in the past decade. The use of multi-spectral data has resulted in the need for finer spatial resolution and greater spectral coverage. Onboard signal processing will be necessary in order to utilize the available Tracking and Data Relay Satellite System (TDRSS) communication channel at high efficiency. A generally recognized approach to the increased efficiency of channel usage is through data compression techniques. The compression technique implemented is a differential pulse code modulation (DPCM) scheme with a non-uniform quantizer. The need to advance the state-of-the-art of onboard processing was recognized and a GaAs integrated circuit technology was chosen. An Adaptive Programmable Processor (APP) chip set was developed which is based on an 8-bit slice general processor. The reason for choosing the compression technique for the Multi-spectral Linear Array (MLA) instrument is described. Also a description is given of the GaAs integrated circuit chip set which will demonstrate that data compression can be performed onboard in real time at data rate in the order of 500 Mb/s

Connection Management in Reconfigurable Distributed Systems

The Programmer\u27s Playground takes a new approach to simplifying and supporting the construction of distributed applications. The approach, called I/O abstraction, separates the description of a system\u27s communication structure from the descriptions of its computational components so that software modules written in existing programming languages cna be integrated flexibly and dynamically by both programmers and end-users. This separation is achieved by estabishing logical connectinos among the data interfaces of independent software modules. The logical connections provide a uniform high-level view of communication for both discrete and continuous data. The I/O abstraction approach inherits ideas from the I/O automaton model, a formal model of distributed computing that provides compositionality properties and supports behavioral specifications of system modules. Implications of I/O abstraction for process migration and the ordering of events in a distributed system will be studied. Software supporting the I/O abstraction programming model will be constructed. A high speed ATM network developed at Washington University will be used as a testbed for the devlopment work. The availability of this campus network offers an unusual opportunity to construct novel distributed (multimedia) applications and to test our ideas in realistic settings. The connection management network protocol (CMNP), the underlying protocol for the ATM networks, will be formally studied by giving a formal specification

On a Model for Integrated Information

In this paper we give a thorough presentation of a model proposed by Tononi et al. for modeling \emph{integrated information}, i.e. how much information is generated in a system transitioning from one state to the next one by the causal interaction of its parts and \emph{above and beyond} the information given by the sum of its parts. We also provides a more general formulation of such a model, independent from the time chosen for the analysis and from the uniformity of the probability distribution at the initial time instant. Finally, we prove that integrated information is null for disconnected systems

The role of use cases in development of a reference framework for interoperability of data exchange in agriculture

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Dynamical Structure Factor for the Alternating Heisenberg Chain: A Linked Cluster Calculation

We develop a linked cluster method to calculate the spectral weights of many-particle excitations at zero temperature. The dynamical structure factor is expressed as a sum of exclusive structure factors, each representing contributions from a given set of excited states. A linked cluster technique to obtain high order series expansions for these quantities is discussed. We apply these methods to the alternating Heisenberg chain around the dimerized limit ($\lambda=0$), where complete wavevector and frequency dependent spectral weights for one and two-particle excitations (continuum and bound-states) are obtained. For small to moderate values of the inter-dimer coupling parameter $\lambda$, these lead to extremely accurate calculations of the dynamical structure factors. We also examine the variation of the relative spectral weights of one and two-particle states with bond alternation all the way up to the limit of the uniform chain ($\lambda=1$). In agreement with Schmidt and Uhrig, we find that the spectral weight is dominated by 2-triplet states even at $\lambda=1$, which implies that a description in terms of triplet-pair excitations remains a good quantitative description of the system even for the uniform chain.Comment: 26 pages, 17 figure