Light Reflectance Characteristics and Remote Sensing of Waterlettuce

Waterlettuce ( Pistia stratiotes L.) is a free-floating exotic aquatic weed that often invades and clogs waterways in the southeastern United States. A study was conducted to evaluate the potential of using remote sensing technology to distinguish infestations of waterlettuce in Texas waterways. Field reflectance measurements showed that waterlettuce had higher visible green reflectance than associated plant species. Waterlettuce could be detected in both aerial color- infrared (CIR) photography and videography where it had light pink to pinkish-white image tonal responses. Computer analysis of CIR photographic and videographic images had overall accuracy assessments of 86% and 84%, respectively. (PDF contains 6 pages.

An extended class of orthogonal polynomials defined by a Sturm-Liouville problem

We present two infinite sequences of polynomial eigenfunctions of a Sturm-Liouville problem. As opposed to the classical orthogonal polynomial systems, these sequences start with a polynomial of degree one. We denote these polynomials as $X_1$-Jacobi and $X_1$-Laguerre and we prove that they are orthogonal with respect to a positive definite inner product defined over the the compact interval $[-1,1]$ or the half-line $[0,\infty)$, respectively, and they are a basis of the corresponding $L^2$ Hilbert spaces. Moreover, we prove a converse statement similar to Bochner's theorem for the classical orthogonal polynomial systems: if a self-adjoint second order operator has a complete set of polynomial eigenfunctions $\{p_i\}_{i=1}^\infty$, then it must be either the $X_1$-Jacobi or the $X_1$-Laguerre Sturm-Liouville problem. A Rodrigues-type formula can be derived for both of the $X_1$ polynomial sequences.Comment: 25 pages, some remarks and references adde

A bioimpedance-based monitor for real-time detection and identification of secondary brain injury

Secondary brain injury impacts patient prognosis and can lead to long-term morbidity and mortality in cases of trauma. Continuous monitoring of secondary injury in acute clinical settings is primarily limited to intracranial pressure (ICP); however, ICP is unable to identify essential underlying etiologies of injury needed to guide treatment (e.g. immediate surgical intervention vs medical management). Here we show that a novel intracranial bioimpedance monitor (BIM) can detect onset of secondary injury, differentiate focal (e.g. hemorrhage) from global (e.g. edema) events, identify underlying etiology and provide localization of an intracranial mass effect. We found in an in vivo porcine model that the BIM detected changes in intracranial volume down to 0.38 mL, differentiated high impedance (e.g. ischemic) from low impedance (e.g. hemorrhagic) injuries (p \u3c 0.001), separated focal from global events (p \u3c 0.001) and provided coarse ‘imaging’ through localization of the mass effect. This work presents for the first time the full design, development, characterization and successful implementation of an intracranial bioimpedance monitor. This BIM technology could be further translated to clinical pathologies including but not limited to traumatic brain injury, intracerebral hemorrhage, stroke, hydrocephalus and post-surgical monitoring

Influence of sedimentary biogeochemistry on oxygen consumption and nutrient cycling in Bellingham Bay, Washington

Bellingham Bay, a shallow, urbanized embayment in north Puget Sound, is experiencing increasing seasonal hypoxia. But, rates of sedimentary geochemical processes that might contribute to this change are not well quantified. This project explored the relationships between sedimentary biogeochemical processes, nutrient fluxes, and oxygen consumption in Bellingham Bay. Working with the Washington State Department of Ecology, we sampled 25 stations throughout the bay, and measured fluxes of dissolved oxygen, dissolved inorganic nitrogen, dissolved inorganic phosphorus, silicate, and dissolved inorganic carbon between sediment and overlying water. We observed decreases in the fluxes of DO, DIC, and DIN with station depth, suggesting that more organic carbon and nitrogen loading is occurring near shore. DIN:DIC and DIP:DIC flux ratios were generally less than those predicted by the Redfield ratio, suggesting that the sediment is a net sink of nitrogen and phosphorus in this coastal embayment. We also found that DO:DIC flux ratio was generally less than the expected 1:1 ratio, indicating production and storage of reduced species such as sulfide, through microbial anaerobic respiration. Further, comparison with water column oxygen consumption rates indicates that total oxygen consumption by the sediment roughly equals oxygen consumption by the water column. These findings suggest that the benthos may play at least two roles in regulating seasonal hypoxia and eutrophication: (1) as a sink for nutrients, which could have some mitigating effect on eutrophication, and (2) as a consumer of water column dissolved oxygen, which could exacerbate seasonal hypoxia. These findings are a crucial step towards linking sedimentary biogeochemical processes with eutrophication and hypoxia in Bellingham Bay

Decrease of cocaine, but not heroin, self-administration and relapse by the tyrosine kinase inhibitor masitinib in male Sprague Dawley rats.

RATIONALE: Accumulating evidence shows that cocaine, and also heroin, influence several tyrosine kinases, expressed in neurons and in non-neuronal populations such as microglia, astrocytes and mast-cells. Drug-induced activation of mast cells both triggers inflammatory processes in the brain mediated by the glial cells they activate, and facilitates histamine release which may directly influence the dopamine system. Thus, by triggering the activation and degranulation of mast cells dependent on the tyrosine kinase c-kit and Fyn, the latter being also involved in NMDA-dependent synaptic plasticity, cocaine and heroin may indirectly influence the neural mechanisms that mediate their reinforcing properties. Masitinib, a novel tyrosine kinase inhibitor with high selectivity for c-Kit, Fyn and Lyn, may alter the aberrant consequences of the activation of these tyrosine kinases by cocaine and heroin. OBJECTIVE: We investigated in rats the effect of a chronic oral treatment with masitinib (20 mg/kg) on the reinforcing and motivational properties of self-administered cocaine (250 μg/infusion) and heroin (40 μg/infusion). METHODS: Three different cohorts of rats were trained instrumentally to respond for cocaine, heroin or food under continuous reinforcement. In each group, we assessed the influence of chronic daily treatment with masitinib on the maintenance of instrumental responding and intake and the motivation for the reinforcer. Thus, masitinib and vehicle-treated rats were challenged to adapt to high behavioural demand, to respond under a progressive ratio schedule of reinforcement and to reinstate instrumental responding after extinction and/or abstinence. RESULTS: Masitinib selectively decreased cocaine intake, the motivation for cocaine and the subsequent propensity to respond for cocaine under extinction, while having no effect on instrumental responding for heroin or food. CONCLUSION: The present findings suggest masitinib, a drug with proven efficacy in CNS disorders, could represent a novel treatment for cocaine addiction provided its influence on the reinforcing and incentive properties of the drug is confirmed

Cyclic polymer liquid crystal structures.

Recent advances in liquid crystal research have included the synthesis of polymeric materials which contain liquid crystalline moieties. The work presented here concerns the study of the structure-property relationships of a particular group of liquid crystalline polymers in which the polymer backbone is cyclic, with the mesogenic moieties attached as side-chains. We have observed mesogenic phases above room temperature for materials comprising cyclic poly(dimethylsiloxane) backbones with mesogenic moieties attached by alkyl spacer units. Dielectric relaxations have been observed in the mesophases of these materials and the activation energies and extent of broadening of the relaxations have been related to the physicalstructure of the molecules. Theoretical studies have been undertaken by the use of the Metropolis Monte Carlo technique and a mean field calculation. Two models have been studied by the Monte Carlo technique in the NVT ensemble. In the first, each complete molecule was represented by a disc-like interactions potential and a tendency for the molecules to align in columns was revealed at low temperature and high density. In the second model, each mesogenic unit was represented separately, with the cyclic polymerrepresented as a constraint on the relative motions of the attached mesogens. A variety of liquid crystalline phases, from discotic nematic to calamitic nematic, were observed at low temperature as the coupling between the side-chains and the backbones was adjusted. In the mean field model energy terms were included for ring-ring interactions, mesogen-mesogen interactions and the coupling between the mesogenic moieties and the backbones. The uniaxial solution of this model also showed a shift from calamitic nematic to discoticnematic phases as the strength of the coupling was increased. Comparisons of the results of the models and the physical measurements are presented and suggestions for future work are proposed

Reconsolidation and extinction are dissociable and mutually exclusive processes: behavioral and molecular evidence.

Memory persistence is critically influenced by retrieval. In rats, a single presentation of a conditioned fear stimulus induces memory reconsolidation and fear memory persistence, while repeated fear cue presentations result in loss of fear through extinction. These two opposite behavioral outcomes are operationally linked by the number of cue presentations at memory retrieval. However, the behavioral properties and mechanistic determinants of the transition have not yet been explored; in particular, whether reconsolidation and extinction processes coexist or are mutually exclusive, depending on the exposure to non-reinforced retrieval events. We characterized both behaviorally and molecularly the transition from reconsolidation to extinction of conditioned fear and showed that an increase in calcineurin (CaN) in the basolateral amygdala (BLA) supports the shift from fear maintenance to fear inhibition. Gradually increasing the extent of retrieval induces a gradual decrease in freezing responses to the conditioned stimulus and a gradual increase in amygdala CaN level. This newly synthesized CaN is required for the extinction, but not the reconsolidation, of conditioned fear. During the transition from reconsolidation to extinction, we have revealed an insensitive state of the fear memory where NMDA-type glutamate receptor agonist and antagonist drugs are unable either to modulate CaN levels in the BLA or alter the reconsolidation or extinction processes. Together, our data indicate both that reconsolidation and extinction are mutually exclusive processes and also reveal the presence of a transitional, or "limbo," state of the original memory between these two alternative outcomes of fear memory retrieval, when neither process is engaged.This research was supported by aUK Medical Research Council Programme Grant (no. 9536855) to B.J.E., and was conducted in the Department of Psychology and the Medical Research Council/Wellcome Trust Behavioural and Clinical Neuroscience Institute. E.M. was supported by a Royal Society Newton International Fellowship. A.L.M. was partly supported by the Ferreras-Willetts Fellowship in Neuroscience at Downing College, Cambridge University.This is the final version of the article. It first appeared from Society for Neuroscience via http://dx.doi.org/10.1523/JNEUROSCI.4001-13.2014

Heroin seeking becomes dependent on dorsal striatal dopaminergic mechanisms and can be decreased by N-acetylcysteine.

The alarming increase in heroin overdoses in the USA is a reminder of the need for efficacious and novel treatments for opiate addiction. This may reflect the relatively poor understanding of the neural basis of heroin, as compared to cocaine, seeking behaviour. While cocaine reinforcement depends on the mesolimbic system, well-established cocaine seeking is dependent on dorsolateral striatum (aDLS) dopamine-dependent mechanisms which are disrupted by N-acetylcysteine, through normalisation of corticostriatal glutamate homeostasis. However, it is unknown whether a functional recruitment of aDLS dopamine-dependent control over instrumental responding also occurs for heroin seeking, even though heroin reinforcement does not depend on the mesolimbic dopamine system. Lister Hooded rats acquired heroin self-administration and were subsequently trained to seek heroin daily over prolonged periods of time under the control of drug-paired cues, as measured under a second-order schedule of reinforcement. At different stages of training, that is, early on and when heroin seeking behaviour was well established, we measured the sensitivity of drug-seeking responses to either bilateral aDLS infusions of the dopamine receptor antagonist α-flupenthixol (5, 10 and 15 μg/side) or systemic administration of N-acetylcysteine (30, 60 and 90 mg/kg). The results demonstrate that control over heroin seeking behaviour devolves to aDLS dopamine-dependent mechanisms after extended training. Further aDLS-dependent well-established, cue-controlled heroin seeking was disrupted by N-acetylcysteine. Comparison with previous data on cocaine suggests that the development of drug seeking habits and the alteration of corticostriatal glutamate homeostasis, which is restored by N-acetylcysteine, are quantitatively similar between heroin and cocaine