cssi/SciSciGPT-SciSciNet huggingface dataset:
The Dynamics of Legged Locomotion: Models, Analyses, and Challenges

Cheetahs and beetles run, dolphins and salmon swim, and bees and birds fly with grace and economy surpassing our technology. Evolution has shaped the breathtaking abilities of animals, leaving us the challenge of reconstructing their targets of control and mechanisms of dexterity. In this review we explore a corner of this fascinating world. We describe mathematical models for legged animal locomotion, focusing on rapidly running insects and highlighting past achievements and challenges that remain. Newtonian body--limb dynamics are most naturally formulated as piecewise-holonomic rigid body mechanical systems, whose constraints change as legs touch down or lift off. Central pattern generators and proprioceptive sensing require models of spiking neurons and simplified phase oscillator descriptions of ensembles of them. A full neuromechanical model of a running animal requires integration of these elements, along with proprioceptive feedback and models of goal-oriented sensing, planning, and learning. We outline relevant background material from biomechanics and neurobiology, explain key properties of the hybrid dynamical systems that underlie legged locomotion models, and provide numerous examples of such models, from the simplest, completely soluble "peg-leg walker" to complex neuromuscular subsystems that are yet to be assembled into models of behaving animals. This final integration in a tractable and illuminating model is an outstanding challenge.
In situ scanning tunneling microscopy studies of the evolution of surface morphology and microstructure in epitaxial TiN(001) grown by ultra-high-vacuum reactive magnetron sputtering

Abstract The group IV-B transition metal nitride TiN is widely employed as a wear-resistant coating on mechanical components and as a diffusion barrier in microelectronic devices. We use the epitaxial growth of TiN as a model system for insight on the evolution of surface morphology and microstructure in more complex polycrystalline films. Atomically-flat MgO(001) substrates, prepared by air annealing at 950 °C for 12 h, are verified by atomic force microscopy (AFM). Epitaxial TiN layers are grown by reactive magnetron sputter deposition in pure N 2 at 650 - T s ≤750 °C. Scanning tunneling microscopy (STM) results show that the development of surface morphology is dominated by growth mounds with an aspect-ratio of ≈ 0.006; both the roughness amplitude and average separation between mounds follow an approximate power law dependence on film thickness, t γ , with γ = 0.25 ±0.07. The films grow in a two-dimensional multilayer mode in which island edges exhibit dendritic geometries characteristic of limited step-edge mobility. Transmission electron microscopy (TEM) shows that the films are epitaxial with dislocation loops on 111 planes and 01misfit dislocations at the interface. Low-energy N 2 + ion irradiation during film growth leads to surface smoothing with the smoothest layers, having a surface width of ≅0.22 nm, obtained with V s = 43 V. Increasing V s ≥43 V leads to surface roughening with decreased in-plane length scales.
Leading in purposive discussions: A study of adaptive behavior

The need to adapt behaviors appropriately to situational constraints and particular members is one aspect of leadership that has received minimal attention from previous research. This study examined the distributional structures of leaders' comments in discussions with differing purposes in an attempt to determine whether leaders adapt their oral behaviors to meet varying goals and to compensate for failures in previous meetings. It was concluded that leaders do adapt oral behaviors to achieve objectives and in response to past failures. This finding suggests that a broad repertoire of possible behaviors is important for successful leaders who find themselves in a variety of discussional situations with divergent goals, members, and constraints.
A novel role for a YXXΦ motif in directing the caveolin-dependent sorting of membrane-spanning proteins

Previous studies showed that the sequence between amino acids 38 and 63 of the chicken AE1-4 anion exchanger is sufficient to direct basolateral sorting and recycling to the Golgi when fused to a cytoplasmic tailless F(c)RII B2 receptor. Further characterization of the recycling pathway has indicated that the chimera F(c)38-63 colocalizes with caveolin 1 in the basolateral membrane of MDCK cells, and in early endosomes following its internalization from the cell surface. Studies using small interfering RNA (siRNA) and dominant-negative mutants revealed that F(c)38-63 endocytosis is primarily caveolin-dependent and clathrin-independent. The endocytosis of the chimera is also dependent upon cholesterol and dynamin. Co-precipitation studies indicated that caveolin 1 associates with F(c)38-63. Mutation of the tyrosine or leucine residues in the cytoplasmic sequence Y(47)VEL of F(c)38-63 disrupts this interaction and inhibits the endocytosis of the chimera. Additional analyses revealed that AE1-4 also associates with caveolin 1. Mutation of the leucine in the Y(47)VEL sequence of AE1-4 disrupts this interaction, and blocks the recycling of this transporter from the basolateral membrane to the Golgi. The Y(47)VEL tetrapeptide matches the sequence of a YXXPhi motif, and our results indicate a novel role for this motif in directing caveolin-dependent sorting.
Energies and symmetries in interface formation: In/GaP(110) and Ga/InP(110)

We have used high‐resolution synchrotron radiation photoemission to study adatom–substrate interactions and growth morphologies for In/GaP(110) and Ga/InP(110). Room‐temperature experiments reveal extensive adatom clustering, but also substrate disruption and cation segregation for both interfaces, with greater amounts for Ga/InP(110). Ga deposition in InP(110) at 60 K also results in substrate disruption, but with kinetic trapping of the released In atoms close to the interface and a greater tendency toward layer‐by‐layer growth. In constrast, the deposition of preformed metallic Ga clusters shows no evidence for substrate disruption. We conclude that atom condensation and coalescence are responsible for disruption, with different activation barriers being present for cluster deposition and atom deposition because of the details of surface and interface bonding. For Ga deposition on n‐type InP(110) at 60 K, the appearance of states at the Fermi level is correlated to changes in band bending. Metal cluste...
Provoking Preferences: Unionization, Trade Policy, and the ILWU Puzzle

If any group of American blue-collar workers has benefited from the growth of trade it is the unionized dockworkers along the US West Coast. Nevertheless, the International Longshore and Warehouse Union (ILWU) representing these workers is vocally opposed to trade liberalization. We examine several competing explanations for this puzzle and evaluate them by tracing the union's stance on trade over several decades. We also use an original survey to compare ILWU affiliates' attitudes on trade with those of nonmembers with otherwise similar characteristics. Consistent with a model of organizational socialization, the data support the hypothesis that ILWU membership affects the members' revealed political opinions; the data are difficult to reconcile with standard theories of international trade. Our findings indicate that the political support for trade depends not just on voters' structural positions in the economy but also on the organizations and networks in which they are embedded.
Pharmacogenomics and End-Organ Susceptibility to Injury in the Perioperative Period

Genomic medicine has provided new mechanistic understanding for many complex diseases over the last 5–10 years. More recently genomic approaches have been applied to the perioperative paradigm, facilitating identification of patients at high risk for adverse events, as well as those who will respond better/worse to specific pharmacologic therapies. The consistent biological theme emerging is that while inflammation is important in healing from surgical trauma, patients who are too robustly proinflammatory appear to be at higher risk for adverse perioperative events. Precise predictors of each adverse event are being elucidated so that corrective therapeutics can be instituted to improve outcomes in high-risk patients. While the field of perioperative genomics could be considered in its infancy, such approaches are the wave of the future.
How do disconnected macropores in sloping soils facilitate preferential flow

Runoff from hillslopes is generated by processes such as infiltration-excess and saturation overland flow, subsurface stormflow and subsurface return flow. Preferential flow through macropores can affect any one of these runoff generation processes. Field studies at the Hitachi Ohta Experimental Watershed in Japan have noted that self-organization processes may manifest the connectivity of such subsurface flow paths, particularly via macropores, from hillslopes to stream channels. It is well established from soil physics principles that the connectivity of macropore networks depends on soil wetness and this has been shown experimentally at Hitachi Ohta where subsurface flow and streamflow respond to thresholds of wetness. Numerical solutions to the three-dimensional Richards equation are derived for a sloping soil block containing a population of disconnected macropores of various sizes, shapes and orientations. Solutions for the case of steady water flux applied to the surface of the soil block are evaluated to determine the conditions where the disconnected macropores become active in the flow process. Results show that subsurface flow is directed through the preferential flow network in the saturated portion of the soil but bypasses the macropores in the drier regions. The preferential flow network expands as the degree of saturation increases. The expanding network of active macropores leads to less resistance to overall flow in the domain and access to increased volumes of the flow domain. Although the individual macropores are disconnected, it is argued that large localized hydraulic gradients can potentially lead to preferred zones of subsurface erosion. In addition to the importance of these findings related to stormflow generation in catchments, they add support to the concept of self-organization of subsurface flow systems in soils. Copyright © 2010 John Wiley & Sons, Ltd.
Organic and inorganic selenium compounds inhibit mouse mammary cell growth in vitro by different cellular pathways

Selenium, both organic and inorganic forms, inhibit mammary tumorigenesis in vivo and mammary cell growth in vitro. In the present study, sodium selenite was compared to methylselenocysteine (MSC) for their individual effects on cell growth, cdc2/cdk2 kinase activities and the levels of cyclins D1, E and A bound to cdk2 in a mouse mammary epithelial cell culture model. Selenite arrested the growth of cells in S-G2-M phase in contrast to MSC which arrested or delayed the cells in G1. In MSC-treated cells there was a 57% drop in the cdk2 kinase activity accompanied by a 73.5% decrease in cyclin E-cdk2 content as compared to the control cells. Selenite treatment increased the cdk2 kinase activity by 30% without any appreciable change in either of the cyclins D1, E or A bound to cdk2 when compared to the control cells. These data support the hypothesis that selenite and MSC have distinct modes of action in the inhibition of cell growth in vitro. Selenite has a strong genotoxic effect on the tumor cells; in contrast, MSC appears to inhibit cell growth via specific inhibition of cell cycle regulatory proteins.
The Mechanisms for Apparent Life-Threatening Events

Infants with a history of an apparent life-threatening event that received mouth-to-mouth resuscitation (ALE-R) are high risk for sudden death (SID). Investigation of 114 infants (median age 2.8 months; 15 with SID in siblings; 20 born preterm) who had single (n=64) or recurrent (50) ALE-R revealed, compared to controls 12, 38 with abnormal hypoxaemia on a 12 hour physiological recording (with accompanying clinical events in 21). Home event recording of TcpO2, breathing movements, ECG ± SaO2 was performed in 46 infants for a median duration 1.4 months: this produced further physiological data in 22 infants.
Improved Sparse Multi-Class SVM and Its Application for Gene Selection in Cancer Classification

Background: Microarray techniques provide promising tools for cancer diagnosis using gene expression profiles. However, molecular diagnosis based on high-throughput platforms presents great challenges due to the overwhelming number of variables versus the small sample size and the complex nature of multi-type tumors. Support vector machines (SVMs) have shown superior performance in cancer classification due to their ability to handle high dimensional low sample size data. The multi-class SVM algorithm of Crammer and Singer provides a natural framework for multi-class learning. Despite its effective performance, the procedure utilizes all variables without selection. In this paper, we propose to improve the procedure by imposing shrinkage penalties in learning to enforce solution sparsity. Results: The original multi-class SVM of Crammer and Singer is effective for multi-class classification but does not conduct variable selection. We improved the method by introducing soft-thresholding type penalties to incorporate variable selection into multi-class classification for high dimensional data. The new methods were applied to simulated data and two cancer gene expression data sets. The results demonstrate that the new methods can select a small number of genes for building accurate multi-class classification rules. Furthermore, the important genes selected by the methods overlap significantly, suggesting general agreement among different variable selection schemes. Conclusions: High accuracy and sparsity make the new methods attractive for cancer diagnostics with gene expression data and defining targets of therapeutic intervention. Availability: The source MATLAB code are available from http://math.arizona.edu/~hzhang/software.html.
A tiling approach to virus capsid assembly explaining a structural puzzle in virology

A novel approach for the description of the protein stoichiometry of viral capsids, that is the protein shells protecting the viral genome, is introduced based on tiling theory. This approach generalizes Caspar–Klug theory of quasi-equivalence to account also for non-quasi-equivalent subunit arrangements in icosahedral virus capsids that have been observed experimentally but are not covered by the Caspar–Klug approach. In particular, the new approach is used to explain the structure of polyoma virus, Simian Virus 40 and L-A virus capsids, which are considered structural puzzles in view of Caspar–Klug theory.
ITERATIVE AND RECURSIVE ALGORITHMS FOR TREE SEARCH AND PARTITION SEARCH OF THE LATTICE OF STRUCTURE MODELS

An important problem in reconstructability analysis, and modelling in general, is determination of the set of simplest models, all of which acceptably represent the information contained in a given overall system. Evaluation of these models depends on acceptability (semantic) criteria and structural criteria. Structural criteria determine whether one model is simpler than another. In this paper we assume the existence of acceptability criteria and mechanisms to determine if given models meet them. The general problem we solve is how to most efficiently generate the set of all models. We use these results to determine the set of simplest models that satisfy the acceptability criteria The main results of the paper are: a procedural definition of a recursive Boolean lattice that is based on recursive partitioning of the set of models, a definition of a spanning tree of the lattice of models, and algorithms for non-duplicating generation and search of the lattice of models. The generation and search algorithm...
Comment on “sampling an autocorrelated process: The AR(1)” by R. G. Craig

Commentaire sur l'article de Craig R.G. paru dans Mathematical geology, USA, 1984, 16, no 8, 745-751
Variable chimerism, graft-versus-host disease, and tolerance after different kinds of cell and whole organ transplantation from Lewis to brown Norway rats.

The persistence of microchimerism in human whole organ recipients years or decades after transplantation (1, 2) reflects the migration long before of bone marrow-derived donor leukocytes from the allografts (3, 4). We have postulated that these immunocompetent donor cells represent one limb of initially antagonistic but ultimately attenuated or abrogated host-versus-graft (HVG,* rejection) and graft-versus-host (GVH) reactions (1-5) (Fig. 1). We describe here a study in rats of the HVG and GVH components of this two-way immunologic paradigm. The clinical and histopathologic expression of the two arms with and without immunosuppression was correlated with the quantity and quality of recipient tissue chimerism and with the development of donor-specific tolerance following transplantation from Lewis (LEW) donors to Brown Norway (BN) recipients of different organs (intestine, liver, heart, kidney) and of different free leukocyte suspensions (bone marrow, lymph nodes, spleen, thymus, and blood). Figure 1 Dualistic immune reactions of host-versus-graft (HVG) and graft-versus-host (GVH) in the two-way paradigm of transplantation immunology. Following the acute reaction, the evolution of tolerance of each leukocyte population to the other is seen as a low-grade ... Although the results leave numerous questions unanswered about basic mechanisms, they cast light on 4 issues that are relevant to planning of clinical tolerance induction protocols: (1) The relative risk of producing clinical GVHD with the tranplantation of different organs and with infusion of a standardized dose of leukocytes obtained from various lymphoid organs, (2) the relative tolerogenicity of the parenchymal organs and the leukocyte suspensions, (3) correlation of 1 and 2 with the density and lineage profile of the chimerism in recipient tissues and, (4) the relation to the quantity and lineage composition of chimerism to chronic rejection.
Novel therapeutic strategies for ischemic heart disease

Despite significant advances in the physician's ability to initiate myocardial reperfusion and salvage heart tissue, ischemic heart disease remains one of the leading causes of death in the United States. Consequently, alternative therapeutic strategies have been intensively investigated, especially methods of enhancing the heart's resistance to ischemic cell death - so called "cardioprotective" interventions. However, although a great deal has been learned regarding the methods and mechanisms of cardioprotective interventions, an efficacious therapy has yet to be successfully implemented in the clinical arena. This review discusses the current understanding of cardioprotection in the context of ischemic heart disease pathophysiology, highlighting those elements of ischemic heart disease pathophysiology that have received less attention as potential targets of cardioprotective intervention.
A Review of Carbon Market Policies and Research

We describe important institutions that shape climate change policies together with a set of key market-reliant instruments. We selectively review the related economic literature, emphasizing empirical studies that assess the efficacy of current policies and the workings of policy-dependent markets. Special attention is given to new carbon finance markets tied to the Kyoto Protocol's flexibility mechanisms. Promising areas for future research are identified.
On the variational foundations of the substitute shape function technique

Abstract In this paper, an element recently developed by Whitcomb (Comput. Struct. 22, 387–398, 1986) along the lines of the so-called substitute shape function technique (SSFT) has been re-examined. It is shown that a varialional basis can be found for this element in the form of a modified version of the variational theorem due to Hellinger and Reissner. On the basis of this theorem, a two-dimensional element has been developed using separate trial functions for the displacements and the shear strain. The element is identical to Whitcomb's element; however, the proposed approach appears to have certain advantages over SSFT.
Geometric programming for optimal allocation of integrated samples in quality control

We apply geometric programming, developed by Duffin, Peterson Zener (1967), to the optimal allocation of stratified samples. As an introduction, we show how geometric programming is used to allocate samples according to Neyman (1934), using the data of Cornell (1947) and following the exposition of Cochran (1953). Then we use geometric programming to allocate an integrated sample introduced by Schwartz (1978) for more efficient sampling of three U. S. Federal welfare quality control systems, Aid to Families with Dependent Children, Food Stamps and Medicaid. We develop methods for setting up the allocation problem, interpreting it as a geometric programming primal problem, transforming it to the corresponding dual problem, solving that, and finding the sample sizes required in the allocation problem. We show that the integrated sample saves sampling costs.
The femoral-based endowedge technique to increase juxtarenal seal and correct graft tilt

The endowedge technique refers to the use of balloons to align the scallops of the Gore Excluder endoprosthesis (W. L. Gore and Associates, Flagstaff, Ariz) to the renal artery to increase juxtarenal seal during endovascular repair of aneurysms with challenging anatomy. With the availability of a reconstrainable deployment system, this now can be performed without the use of brachial access. In addition, the femoral approach facilitates the use of the balloon as a fulcrum to correct unfavorable graft tilt.
A general purpose simulation environment for neural models

Current interest in neural networks has produced a diverse set of algorithms and architectures that vary in connectivity pattern, temporal behavior, update rules, and convergence properties. We have designed a flexible simulation system that can support the implementation of a wide range of neural network approaches. The UCLA-SFINX simulator is especially suited for the exploration of structured, irregular, and layered connectivity patterns. Func tions, such as those in early vision, are modeled using the regular connectivity of center/surround antagonistic receptive fields and can be implemented as the difference of concentric gaussians. Higher level cognitive functions, such as supervised and unsuper vised learning, have more irregular, dynamic connectivity structures and update mechanisms that are also supported. To visualize weight spaces, input/output training sets, image data, or other network characteristics, SFINX provides an X- windows based graphical output that assists in rapidly assessing the ...
Prevalence of sleep disturbance in a primarily urban Florida county

Abstract Data for this paper originated from the Florida Health Study Program, a comprehensive survey eliciting general health information from a random sample of 1645 individuals in Alachua County, Florida. Patterns of socio-demographic differences were studied for each of six questionnaire items relating to sleep. More than one-third of respondents reported having trouble with sleep. This was greatest for older non-single females at a low SES level but unrelated to race. Use of sleeping medications was highest among older white females, but unrelated to race, SES, and marital status. Life-style implications were reflected in types of sleeping difficulty.
Nitric oxide metabolites induced in Anopheles stephensi control malaria parasite infection

Malaria parasite infection in anopheline mosquitoes is limited by inflammatory levels of nitric oxide metabolites. To assess the mechanisms of parasite stasis or toxicity, we investigated the biochemistry of these metabolites within the blood-filled mosquito midgut. Our data indicate that nitrates, but not nitrites, are elevated in the Plasmodium-infected midgut. Although levels of S-nitrosothiols do not change with infection, blood proteins are S-nitrosylated after ingestion by the mosquito. In addition, photolyzable nitric oxide, which can be attributed to metal nitrosyls, is elevated after infection and, based on the abundance of hemoglobin, likely includes heme iron nitrosyl. The persistence of oxyhemoglobin throughout blood digestion and changes in hemoglobin conformation in response to infection suggest that hemoglobin catalyzes the synthesis of nitric oxide metabolites in a reducing environment. Provision of urate, a potent reductant and scavenger of oxidants and nitrating agents, as a dietary supplement to mosquitoes increased parasite infection levels relative to allantoin-fed controls, suggesting that nitrosative and/or oxidative stresses negatively impact developing parasites. Collectively, our results reveal a unique role for nitric oxide in an oxyhemoglobin-rich environment. In contrast to facilitating oxygen delivery by hemoglobin in the mammalian vasculature, nitric oxide synthesis in the blood-filled mosquito midgut drives the formation of toxic metabolites that limit parasite development.
Trifluoromethanesulfonato complexes of nickel and cobalt

Abstract Nickel(II) and Cobalt(II) compounds of general formula [ML4(CF3SO3)2] are reported (L = pyridine, 3-methylpyridine, 4-methylpyridine, 3,5-lutidine, 4-ethylpyridine, and 4-isopropylpyridine). Infrared and electronic spectra and magnetic susceptibility measurements indicate that all are high-spin six coordinate complexes. Upon evaluation of crystal field parameters, Ds and Dt, it was found that the trifluoromethanesulfonate anion coordinates more strongly than perchlorate and tetrafluoroborate, but less strongly than perrhenate, chloride, and bromide.
Interactive inductive learning

Abstract We propose an interactive probabilistic inductive learning model which defines a feedback relationship between the user and the learning program. We extend previously described learning algorithms to a conditional model previously described by the authors, and formulate our Conditional Probabilistic Learning Algorithm (CPLA), applying conditions as introduced by Wasilewska to a probabilistic version of the work of Wong and Wong. We propose the Condition Suggestion Algorithm (CSA) as a way to use the syntactic knowledge in the system to generalize the family of decision rules. We also examine the semantic knowledge of the system implied by the suggested conditions and analyse the effects of conditions on the system. CPLA/CSA has been implemented by the first author and was used to generate the examples presented.
A quantitative fluorescent method for measurement of bacterial adherence and phagocytosis

Abstract We have developed a new two-color fluorescent method for the quantitative measurement of adherence and ingestion of Streptococcus pneumoniae by human monocytes. The method employs a fluorescent naphthalimide, Lucifer Yellow VS, that has been covalently linked to the bacterial cell wall. Bacteria were opsonized and allowed to adhere to monocytes. Lucifer Yellow did not alter bacterial interaction with complement in serum or with the phagocytic cell. The ability of monocytes to ingest the adherent bacteria was tested under a variety of conditions. Rabbit antibody to Lucifer Yellow derivatized with Texas Red was used to detect monocyte-bound, but uningested bacteria. Dual laser flow cytometry simultaneously quantitated the total number of monocyte-associated S. pneumoniae and the number that remained surface adherent. This method allows separate analysis of the opsonins and receptors involved in bacterial adherence to phagocytes and in the ingestion process.
Revisiting the association between attention-deficit/hyperactivity disorder and anxiety disorders: a familial risk analysis

Abstract Background This study tested competing hypotheses about patterns of familial association between attention-deficit/hyperactivity disorder (ADHD) and anxiety disorders using familial risk analysis methodology. Methods The risk for ADHD and anxiety disorders in first-degree relatives was examined after stratifying ADHD probands by the presence or absence of comorbid anxiety disorders. The presence of anxiety disorders in probands and relatives was defined as meeting DSM-III-R diagnostic criteria for ≥2 anxiety syndromes in the same subject. Results Familial risk analyses revealed that 1) the risk for anxiety disorders was significantly higher in ADHD probands and their relatives than in control probands and their relatives; 2) the risk for anxiety disorders among the relatives of ADHD probands was limited to those families in which the proband had a diagnosis of ADHD; 3) the risk for anxiety disorders was significantly higher among the relatives of ADHD probands with anxiety disorders than in relatives of ADHD probands without anxiety disorders, but these two groups did not differ in the familial risk for ADHD; and 4) ADHD and anxiety disorders did not cosegregate within families, and there was no evidence for nonrandom (assortative) mating. Conclusions These findings are most consistent with the hypothesis that ADHD and anxiety disorders segregate independently in families.
Loss of Pde6 reduces cell body Ca2+ transients within photoreceptors

Modulation of Ca2+ within cells is tightly regulated through complex and dynamic interactions between the plasma membrane and internal compartments. In this study, we exploit in vivo imaging strategies based on genetically encoded Ca2+ indicators to define changes in perikaryal Ca2+ concentration of intact photoreceptors. We developed double-transgenic zebrafish larvae expressing GCaMP3 in all cones and tdTomato in long-wavelength cones to test the hypothesis that photoreceptor degeneration induced by mutations in the phosphodiesterase-6 (Pde6) gene is driven by excessive [Ca2+]i levels within the cell body. Arguing against Ca2+ overload in Pde6 mutant photoreceptors, simultaneous analysis of cone photoreceptor morphology and Ca2+ fluxes revealed that degeneration of pde6cw59 mutant cones, which lack the cone-specific cGMP phosphodiesterase, is not associated with sustained increases in perikaryal [Ca2+]i. Analysis of [Ca2+]i in dissociated Pde6βrd1mouse rods shows conservation of this finding across vertebrates. In vivo, transient and Pde6-independent Ca2+ elevations (‘flashes') were detected throughout the inner segment and the synapse. As the mutant cells proceeded to degenerate, these Ca2+ fluxes diminished. This study thus provides insight into Ca2+ dynamics in a common form of inherited blindness and uncovers a dramatic, light-independent modulation of [Ca2+]i that occurs in normal cones.
The effect of paired neutral stimuli on the acquisition and extinction of the classical eyeblink response

The effect of pairing two neutral stimuli at the same inter-stimulus interval subsequently used for conditioning the eye-blink response was compared to an unpaired control group and no differences were found during acquisition. The neutral stimulus used in preacquisition subsequently was found to have a retarding effect on extinction, but there was no difference between Ss who had received paired and unpaired neutral stimuli initially.
NMR and EPR Spectroscopic and Structural Studies of Low-Spin, (dxz,dyz)4(dxy)1 Ground State Fe(III) Bis-tert-Butylisocyanide Complexes of Dodecasubstituted Porphyrins†

The bis-(1,1-dimethylethylisocyanide) (tert-butylisocyanide) complexes of three iron porphyrinates (2,3,7,8,12,13,17,18-octaethyl-5,10,15,20-tetraphenylporphyrin, OETPP; 2,3,7,8,12,13,17,18-octamethyl-5,10,15,20-tetraphenylporphyrin, OMTPP; and 2,3,7,8,12,13,17,18-tetra-β,β‘-tetramethylene-5,10,15,20-tetraphenylporphyrin, TC6TPP) have been prepared and studied by EPR and 1H NMR spectroscopy. From EPR and NMR spectroscopic results it has been found that the ground states of the bis-(t-BuNC) complexes of OETPP, OMTPP, and TC6TPP are represented mainly (99.1−99.4%) as (dxz,dyz)4(dxy)1 electron configurations, with an excited state lying 700 cm-1 to higher energy for the OMTPP complex, and probably at lower and higher energies, respectively, for the OETPP and TC6TPP complexes. In the 1H NMR spectra the (dxz,dyz)4(dxy)1 electron configurations of all three complexes are indicated by the large and positive meso-phenyl-H shift differences, δm−δo and δm−δp, and close to the diamagnetic shifts of groups (CH3 or CH...
Spontaneous Hereditary Mutation for a Recurrent Hairless Condition in Mice

A SPONTANEOUS mutation has appeared in the thirty-first generation of a sib-mated control line in a radiation genetics programme being carried out at this laboratory. This mutation affects the hair coat and produces a hairless condition (Fig. 1) which appears intermittently in mutant mice. This communication provides a brief account of the mutation.
A team theoretic approach to decentralized control of systems with stochastic parameters

This paper investigates an optimal decentralized control problem for a system with B-matrices dependent on stochastic parameters. It is assumed that these parameters are independent in time and available locally to each controller. The objective is to find a decentralized state feedback control policy that minimizes a multi step quadratic cost function. We first solve this problem for the case of one time step and show that the optimal policy can be reached through iterating the best responses of each player. For the optimal multiple step problem, a dynamic programming approach is employed while using the result of the one step control at each step. Finally in the infinite horizon case, we provide sufficient conditions under which the optimal control policy is unique and stabilizes the system in a mean square sense.
Presence and localization of immunoreactive luteinizing hormone-releasing hormone (LHRH) within the olfactory bulbs of adult male and female rats.

A sensitive and specific radioimmunoassay was employed to measure the immunoreactive luteinizing hormone releasing hormone (LHRH) concentration from localized areas within the olfactory bulbs of adult male and female rats. Although no significant sex differences or lateralization were obtained LHRH concentration within the posterior half of the olfactory bulb was significantly greater than that obtained in the anterior half for both males and females. The presence of LHRH within the olfactory bulbs and localization to areas involved in the chemical stimulation of reproductive processes suggests the possibility that this olfactory bulb LHRH may be involved in mediating pheromonally stimulated endocrinological responses.
Characteristics and applications of the cold heat exergy of liquefied natural gas

Abstract A mathematical model for predicting the low temperature exergy, pressure exergy and total cold heat exergy of Liquefied Natural Gas (LNG) is developed in this paper. In the model, the liquid mixture densities are calculated by a shape factor Corresponding State method, Vapor–Liquid-Equilibrium data of LNG are predicted by an improved method and the influences of real fluid effects are considered. The model is used to determine the various exergies, and the influences of ambient temperature, system pressure and mixture component concentrations on the cold heat exergies are analyzed. Different schemes for applying the low temperature exergy and pressure exergy are proposed. Based on the modeling results, it is proposed that the schemes for applying the cold heat exergies of LNG be determined by thermodynamic cycle optimization, while considering the magnitudes of low temperature exergy and pressure exergy, as well as the required gas supply pressures.
Magnetic and high-pressure magnetotransport properties of cesium-substituted lanthanum calcium manganites

The nature of the double-exchange (DE) interaction in lanthanum manganites is studied through chemical substitutions, Cs for La, and high-pressure measurements. Static and high-frequency magnetic measurements and high-pressure electrical transport studies were carried out on bulk polycrystalline and radio-frequency sputtered thin films of La0.7-xCsxCa0.3MnO3 for x=0-0.1. The samples are found to be cubic. Curie temperature Tc measurements provide evidence for bond-length-related weakening of DE as x is increased from 0 to 0.03. For higher x, the bond-angle-related changes lead to an increase in the strength of DE. High-pressure mangetoresistance data indicate both bond length and bond-angle-related increase of 10–20 K/GPa in Tc with pressure, with the largest increase measured for x=0.03. The rate of increase in the Curie temperature with pressure decreases with increasing Tc. Anomalies are observed in the magnetic parameters for x=0.03. The Cs-concentration dependence of the low-temperature saturation magnetization shows a minimum close to x=0.03. Ferromagnetic resonance studies at x-band reveal a 5% decrease in the g-value for x=0.03 relative to the end members (x=0 and 0.1). The low-field magnetostriction for x=0.03 indicates a relatively strong electron–phonon spin coupling compared to neighboring compositions.
Concealed Retrograde Conduction in Complete Atrioventricular Block

Atrio-ventricular (A-V) conduction and retrograde concealed conduction were assessed in 13 patients with complete heart block distal to the His bundle. Antegrade conduction was defined by His bundle study. The presence or absence of retrograde concealed conduction of the atrio-ventricular node was determined during ventricular pacing. Four instances of retrograde concealed conduction of the A-V node were observed.
Cosmic-ray air-shower thickness timing analyses: expanding a small array's acceptance

A new, small-scale, detector utilizing the finite thickness of air-shower "pancakes" has been developed and operated on the roof of the physics building at the University of Minnesota. (MR. CRATE = Minnesota Rooftop Cosmic-Ray Air-shower Timing Experiment). Such techniques were pioneered by Linsley and collaborators, carried forth in a variety of forms through the 1970s-80s, and with differing technologies by Watson and colleagues. The primary interest in such detector is the ability to use timing of the air shower to allow the array to trigger on events that fall outside of the array. In principal, one can use a single detector to observe air showers out to a distance at which the detector runs out of statistics. The Mark-I detector was simply that. More extensive detectors using these techniques have also been designed and built with an eye towards incorporating them into existing underground or surface air shower detectors. Preliminary results and design studies will be discussed.
Spectroscopic and chromatographic studies of organic carbon in recent marine sediments from the Peruvian Upwelling Zone

Abstract Early diagenesis of organic matter in sediments from two sites in the Peruvian Upwelling Zone (12°05′S, 77°39′W; 15°17′S, 75°24′W) has been studied by observing changes in the total organic carbon and lipid and humin fractions with depth. Transformations of the total carbon and humin fraction have been characterized by conventional and time-dependent solid state NMR techniques, while lipid diagenesis was monitored by measuring the concentration of sterols in the same sedimentary horizons. Both the quantity of total sterols and the relative abundances of individual sterols vary with sampling location, suggesting a difference in the input of biomass to the sediments at the two sites. Total sterol concentrations decrease with depth at both sites, but the loss of sterols occurs much more slowly at the more anoxic northern site, where sedimentation rates and organic carbon contents are approximately twice those at the southern site. 13 C-NMR spectra of the total organic carbon and the humin fraction suggest that humin-like compounds are an original component of the sedimentary biomass, and dipolar-dephased spectra of the humin residue indicate that diagenetic alterations of the humin fraction are occurring even in these very young sediments. Conventional and time-dependent spectroscopic data support the hypothesis that humin formation results from selective preservation of microbially-resistant biopolymers which are an original component of the sedimentary biomass combined with loss of certain labile compounds.
Noble liquid detectors for fundamental physics and applications

Noble liquid detectors come in many sizes and configurations and cover a lot of ground as particle and radiation detectors: from calorimeters for colliders to imaging detectors for neutrino physics and proton decay to WIMP Dark Matter detectors. It turns out that noble liquid detectors are a mature technology for imaging and spectroscopy of gamma rays and for neutron detection, a fact that makes them suitable for applications, e.g. cargo scanning and Homeland Security. In this short paper I will focus on liquid xenon and liquid argon, which make excellent detectors for hypothetical WIMP Dark Matter and neutrinos and for much less exotic gamma rays.
Effect of Postmilking Teat Antisepsis on Teat Canal Infections in Lactating Dairy Cows

Effects of a .18% iodophor teat dip and a fatty acid plus lactic acid teat dip on teat canal infections were studied in two separate trials under experimental challenge procedures using Staphylococcus aureus and Streptococcus agalactiae. The iodophor teat dip was 90% effective in preventing new S. aureus teat canal infections and 95.6% effective in reducing progression of S. aureus teat canal infections to intramammary infections. The dip also reduced persistence of S. aureus teat canal colonizations from week to week by 94.4%. The fatty acid plus lactic acid dip had no effect on preventing S. aureus teat canal infections but reduced progression of S. aureus teat canal infections to intramammary infections by 43.8%. The fatty acid plus lactic acid dip also reduced the persistence of S. aureus teat canal infections by 39%. An insufficient number of Strep. agalactiae teat canal infections was detected in both trials for valid analyses. Neither dip had any effect on prevalence of naturally occurring, coagulase-negative staphylococcal teat canal infections or on teat canal infections by other organisms.
Time lag for posting transmission-based isolation precaution signs.

Background Rapid identification and isolation of patients colonized or infected with virulent pathogens is essential to minimize risk of exposure to other patients, visitors, and health care workers. Objective Our objective was to determine the time lag between when a patient is identified as requiring isolation precautions and when an isolation sign is posted outside of their room. Methods Patients requiring assessment of isolation precautions because of a new positive culture, readmission, or transfers within the institution were identified through an electronic surveillance system. Observers recorded the presence of isolation signs at the patient's door at time (T) 0hr, T2hr, T4hr, T24hr, and T48hr or until an isolation sign was posted. Results The majority of patients was adults in nonintensive care units. Isolation signs were present for 79.0% of the patients at T0hr and increased to 83.8% by T48hr. No difference was seen between the unit type or indications for isolation. The most common organisms for which isolation was indicated were influenza and resistant enterococci, Staphylococcus aureus ; isolation sign postings at T0hr were 87.9%, 85.7%, and 80.7%, respectively. There was a significant difference seen in compliance among the adult (82.8%) and pediatrics (66.7%) sites ( P = .0268). Conclusion Isolation precautions are indicated to prevent transmission of virulent pathogens; however, their implementation in a timely manner can be challenging. In this study, approximately 20% of patients for whom isolation was needed had no sign posted within the first 24 hours, and there were only minimal increases thereafter. Simple processes are needed for early identification of patients, communication of the protective equipment needed, and continuous monitoring of adherence to guidelines.
Primary Prevention in University Residence Halls: Paraprofessional‐Led Relationship Enhancement Groups for College Roommates

The author examined the effect of Relationship Enhancement training as a preventive intervention with college roommates. Trained paraprofessional counselors (resident assistants) led 20 Relationship Skills Workshops for students in their living units. The workshops (four 2-hour sessions each) were based on the Relationship Enhancement method and involved training students in expressive (subjective self-disclosure) and empathic (demonstrating understanding) skills. Students were randomly assigned to workshops either early (experimental group) or late (delayed treatment control group) in the semester. Assessments of students' expressive and empathic skills when discussing personal concerns and conflicts with their roommates were made on all participants at the beginning, middle, and end of the semester. Results show significantly higher level skills for the trained experimental group in comparison to the as-yet untrained delayed-treatment control group at the middle of the semester, and that significant improvement occurred in both groups following their respective participation in training, suggesting training was effective.
Trypsin interaction with the senile plaques of Alzheimer disease is mediated by β-protein precursor

In this study we demonstrate byin situ binding that trypsin interacts with the senile plaques found in Alzheimer disease. Characterization of various potential trypsin binding proteins shows that trypsin binding is mediated by β-protein precursor (βPP)—the progenitor of amyloid-β in senile plaques. Using specific antisera against various proteins to sterically block trypsin blocking, we found that only those antibodies raised against proteins or peptides containing the Kunitz protease inhibitor domain were able to abolish binding. By analogy with other protease/inhibitor interactions, we speculate that the binding of trypsin to βPP could involve concomitant βPP cleavage. Therefore, βPP in protecting against potentially damaging proteolysis could simultaneously liberate βPP fragments or intermediate precursors of amyloid-β deposits.
Relationship of cation influxes and effluxes in yeast.

The Na+ efflux from Na+-rich yeast cells into a cation-free medium is largely balanced by the excretion of organic anions. In the presence of Rb+, K+, or high levels of H+ (pH 3–4), the Na+ efflux is increased and the organic anion excretion is suppressed so that stoichiometric cation exchanges occur. H+ participates in the exchanges, moving into or out of the cells depending on the external pH and on the concentration of external Rb+(K+). The total cation efflux is dependent on the external Rb+ concentration in a "saturation" relationship, but the individual cations in the efflux stream are not. The discrimination factor in the efflux pathway between H+ and Na+ is very large (of the order of 10,000), and between Na+ and K+ considerable (of the order of 50). For the latter pair, the recycling of K+ from the cell wall space is an important factor in the discrimination. In addition, the Na+ efflux as a function of Na+ content follows a sigmoidal curve so that the discrimination factor is increased at high levels of cellular Na+. Although the influx and efflux pathways behave as a tightly coupled system, the mechanism of coupling is not entirely clear. A single system with different cation specificities and kinetic behaviors on the inside and outside faces of the membrane could account for the data.
Calibrating the ChemCam laser-induced breakdown spectroscopy instrument for carbonate minerals on Mars

The ChemCam instrument suite onboard the NASA Mars Science Laboratory rover includes the first laser-induced breakdown spectroscopy (LIBS) instrument for extraterrestrial applications. Here we examine carbonate minerals in a simulated martian environment to better understand the LIBS signature of these materials on Mars. Both chemical composition and rock type are determined using multivariate analysis techniques. Composition is confirmed using scanning electron microscopy. Our results show that ChemCam can recognize and differentiate between different types of carbonate materials on Mars.