Adrenergic and Glutamergic Receptor Gene Expression and Their Functional regulation in the Cerebral Cortex of Hypoxia Induced Neonatal Rats:Role of Oxygen,Epinephrine and Glucose Supplementation

In the present work, the role of oxygen, epinephrine and glucose supplementation in regulating neurotransmitter contents, adrenergic and glutamate receptor binding parameters in the cerebral cortex of experimental groups of neonatal rats were investigated. The study of neurotransmitters and their receptors in the cerebral cortex and the EEG pattern in the brain regions of neonatal rats were taken as index for brain damage due to hypoxia, oxygen and epinephrine. Real-Time PCR work was done to confirm the binding parameters. Second messenger, cyclic Adenosine Monophosphate (cAMP) was assayed to find the functional correlation of the receptors. Behavioural studies were carried out to confirm the biochemical and molecular studies. The efficient and timely supplementation of glucose plays a crucial role in correcting the molecular changes due to hypoxia, oxygen and epinephrine. The addictive neuronal damage effect due to oxygen and epinephrine treatment is another important observation. The corrective measures from the molecular study brought to practice will lead to maintain healthy intellectual capacity during the later developmental stages, which has immense clinical significance in neonatal care.

Phytochemical investigations on ‘black glumed’ Njavara (Oryza sativa L.), the medicinal rice, as compared to staple varieties and evaluation of their antioxidant, anti-inflammatory and anticancer effects

The study was planned to investigate the bioactive compounds in Njavara compared to staple varieties and their bioactivity to substantiate the medicinal properties. Results of the study on chemical indices, antioxidant activity and antiinflammatory activity (in vivo) of Njavara black rice bran and rice in comparison with non-medicinal varieties like Sujatha and Palakkadan Matta rice bran and rice are given. The phytochemical investigation and quantification of Njavara extracts in comparison with staple varieties are detailed in this study. The last chapter is divided in three sections (A, B and C). Section A comprises the antioxidant activity by in vitro assays like DPPH, superoxide anion radical and hydrogen peroxide scavenging activity of the compounds. Also, theoretical studies using DFT were carried out based on DPPH radical scavenging activity for understanding the radical stability and mechanism of antioxidant activity. Section B comprises the anti-inflammatory activity of the identified compounds namely tricin and two flavonolignans in both in vivo and in vitro models. Section C describes the cytotoxicity of the rare flavonolignans, tricin 4’-O-(erythro-β-guaiacylglyceryl) ether and tricin 4’-O-(threo-β-guaiacylglyceryl) ether towards multiple cancer cells belonging to colon, ovarian and breast tumours.

Cholinergic receptor subtypes functional regulation in spinal cord injured monoplegic rats

The present study deals with the Cholinergic Receptor subtypes functional regulation in spinal cord injured monoplegic rats: Effect of 5-HT GABA and bone marrow cells.Spinal cord injury causes permanent and irrevocable motor deficits and neurodegeneration. Disruption of the spinal cord leads to diminished transmission of descending control from the brain to motor neurons and ascending sensory information. Behavioural studies showed deficits in motor control and coordination in SCI rats. Cholinergic system plays an important role in SCI, the evaluation of which provides valuable insight on the underlying mechanisms of motor deficit that occur during SCI. The cholinergic transmission was studied by assessing the muscarinic and nicotinic receptors; cholinergic enzymes- ChAT and AChE; second messenger enzyme PLC; transcription factor CREB and second messengers - IP3, cAMP and cGMP. We observed a decrease in the cholinergic transmission in the brain and spinal cord of SCI rats. The disrupted cholinergic system is the indicative of motor deficit and neuronal degeneration in the spinal cord and brain regions. SCI mediated oxidative stress and apoptosis leads to neuronal degeneration in SCI rats. The decreased expression of anti oxidant enzymes – SOD, GPx and neuronal cell survival factors - BDNF, GDNF, IGF-1, Akt and cyclin D2 along with increased expression of apoptotic factors – Bax, caspase-8, TNFa and NF-kB augmented the neuronal degeneration in SCI condition. BMC administration in combination with 5-HT and GABA in SCI rats showed a reversal in the impaired cholinergic neurotransmission and reduced the oxidative stress and apoptosis. It also enhanced the expression of cell survival factors in the spinal cord region. In SCI rats treated with 5-HT and GABA, the transplanted BMC expressed NeuN confirming that 5-HT and GABA induced the differentiation and proliferation of BMC to neurons in the spinal cord. Neurotrophic factors and anti-apoptotic elements in SCI rats treated with 5-HT and GABA along with BMC rendered neuroprotective effects accompanied by improvement in behavioural deficits. This resulted in a significant reversal of altered cholinergic neurotransmission in SCI. The restorative and neuro protective effects of BMC in combination with 5-HT and GABA are of immense therapeutic significance in the clinical management of SCI.

Serotonin receptor subtypes functional regulation and oxidative stress mediated apoptosis in 6-hydroxydopamine lesioned Parkinsonian rats

Parkinson’s disease is a chronic progressive neurodegenerative disorder characterized by the selective loss of dopaminergic neurons in the SNpc resulting in severe motor impairments. Serotonergic system plays an important regulatory role in the pathophysiology of PD in rats, the evaluation of which provides valuable insight on the underlying mechanisms of motor, cognitive and memory deficits in PD. We observed a decrease in 5-HT content in the brain regions of 6-OHDA infused rat compared to control. The decreased 5-HT content resulted in a decrease of total 5-HT, 5-HT2A receptors and 5-HTT function and an increase of 5-HT2C receptor function. 5-HT receptor subtypes - 5-HT2A and 5-HT2C receptors have differential regulatory role on the modulation of DA neurotransmission in different brain regions during PD. Our observation of impaired serotonergic neurotransmission in SNpc, corpus striatum, cerebral cortex, hippocampus, cerebellum and brain stem demonstrate that although PD primarily results from neurodegeneration in the SNpc, the associated neurochemical changes in other areas of the brain significantly contributes to the different motor and non motor symptoms of PD. The antioxidant enzymes – SOD, CAT and GPx showed significant down regulation which indicates increased oxidative damage resulting in neurodegeneration. We also observed an increase in the level of lipid peroxidation. Reduced expression of anti-apoptotic Akt and enhanced expression of NF-B resulting from oxidative stress caused an activation of caspase-8 thus leading the cells to neurodegeneration by apoptosis. BMC administration in combination with 5-HT and GABA to PD rats showed reversal of the impaired serotonergic neurotransmission and oxidative stress mediated apoptosis. The transplanted BMC expressed NeuN confirming that 5-HT and GABA induced the differentiation and proliferation of BMC to neurons in the SNpc along with an increase in DA content and an enhanced expression of TH. Neurotrophic factors – BDNF and GDNF rendered neuroprotective effects accompanied by improvement in behavioural deficits indicating a significant reversal of altered dopaminergic and serotonergic neurotransmission in PD. The restorative and neuroprotective effects of BMC in combination with 5-HT and GABA are of immense therapeutic significance in the clinical management of PD.

Actinomycete Isolates from Arabian Sea and Bay of Bengal: Biochemical, Molecular and Functional Characterization

The thesis is comprised of seven chapters. Chapter 1 gives a general introduction to marine actinomycetes; Chapter 2 gives an account on the morphological, biochemical and physiological characterization of marine actinomycetes. Comprehensive description of molecular identification and phylogenetic analysis of actinomycetes is dealt with in Chapter 3. The antimicrobial property with special reference to antivibrio activity is described in Chapter 4. Chapter 5 explores the melanin production ability of marine actinomycetes, characterization of melanin and evaluation of its bioactivity. Chapter 6 illustrates the study on chitinolytic Streptomyces as antifungal and insecticidal agents. Summary and Conclusion of the study is presented in Chapter 7, followed by References and Appendices.The present study provides an insight into the various actinomycetes occurring in the sediments of Arabian Sea and Bay of Bengal. Streptomyces was found to be the dominant group followed by Nocardiopsis. Eventhough generic level identification is possible by traditional phenotypic methods, species level identification necessitate a polyphasic approach including both phenotypic and genotypic characterization. Antibiotic production coupled with biogranulation property helped in the effective utilization of the actinomycetes for the control of vibrios. Melanin from Streptomyces bikiniensis was proved to be a promising antioxidant and photoprotectant. Marine actinomycetes were found to be a good source of hydrolytic enzymes and the chitinolytic isolates could be explored as biocontrol agents in terms of antifungal and insecticidal property. The present study explored the potential of marine actinomycetes especially Streptomycetes as a promising source of bioactive molecules for application in aquaculture and pharmaceutical industry.

Seismic behavior of capacity designed masonry walls in low seismicity regions

Eurocode 8 representing a new generation of structural design codes in Europe defines ‎requirements for the design of buildings against earthquake action. In Central and ‎Western Europe, the newly defined earthquake zones and corresponding design ground ‎acceleration values, will lead in many cases to earthquake actions which are remarkably ‎higher than those defined so far by the design codes used until now in Central Europe. ‎ In many cases, the weak points of masonry structures during an earthquake are the corner ‎regions of the walls. Loading of masonry walls by earthquake action leads in most cases ‎to high shear forces. The corresponding bending moment in such a wall typically causes a ‎significant increase of the eccentricity of the normal force in the critical wall cross ‎section. This in turn leads ultimately to a reduction of the size of the compression zone in ‎unreinforced walls and a high concentration of normal stresses and shear stresses in the ‎corner regions. ‎ Corner-Gap-Elements, consisting of a bearing beam located underneath the wall and ‎made of a sufficiently strong material (such as reinforced concrete), reduce the effect of ‎the eccentricity of the normal force and thus restricts the pinching effect of the ‎compression zone. In fact, the deformation can be concentrated in the joint below the ‎bearing beam. According to the principles of the Capacity Design philosophy, the ‎masonry itself is protected from high stresses as a potential cause of brittle failure. ‎ Shaking table tests at the NTU Athens Earthquake Engineering Laboratory have proven ‎the effectiveness of the Corner-Gap-Element. The following presentation will cover the ‎evaluation of various experimental results as well as a numerical modeling of the ‎observed phenomena.‎

Assembly Design and Evaluation in an Augmented Reality Environment

The technologies and methodologies of assembly design and evaluation in the early design stage are highly significant to product development. This paper looks at a promising technology to mix real components (e.g. physical prototypes, assembly tools, machines, etc.) with virtual components to create an Augmented Reality (AR) interface for assembly process evaluation. The goal of this paper is to clarify the methodologies and enabling technologies of how to establish an AR assembly simulation and evaluation environment. The architecture of an AR assembly system is proposed and the important functional modules including AR environment set-up, design for assembly (DFA) analysis and AR assembly sequence planning in an AR environment are discussed in detail.

La provincia en Boyacá : unidad territorial, histórico-funcional de planificación en la gestión del desarrollo regional endógeno. 2004-2011

Se ha dicho que el Desarrollo Regional Endógeno implica el cambio social sostenido que lleve al perfeccionamiento de una región. Para que se dé ese cambio, es necesario partir de la activación de las capacidades internas lo que implícitamente incluye la organización del territorio. Dicha organización para el caso de Boyacá es la Provincia o Provincias. Y lo es debido a que la provincia como unidad territorial es un lugar concreto de la acción política, donde es factible organizar la sociedad y donde se pueden coordinar sus necesidades por medio de la participación. Lo es también, ya que la provincia es resultado de los usos del territorio a través del tiempo, no es un capricho ni es resultado del azar o de los intereses de algunos, es pues unidad histórica. Y lo es, porque implica reconocer que la disposición del territorio con miras a una función y usos determinados, unidad funcional, es definitiva en la capacidad territorial de toma de decisión, en la elección, el diseño, la ejecución y la evaluación de políticas; es decir, en el proceso de Gestión Pública que involucra la Planificación y que se alimenta asimismo de ella. La provincia es la unidad territorial (lugar concreto de acción) histórico (trascendente) funcional (que se emplea) para la Planificación en la Gestión del Desarrollo Regional Endógeno en Boyacá.

Evolution of clinical and functional results after arthroscopic treatment of Discoid Meniscus. A case series study of 31 cases.

Purpose: To evaluate the evolution of clinical and functional outcomes of symptomatic discoid lateral meniscus treated arthroscopically over time and to investigate the relationship between associated intra-articular findings and outcomes. Methods: Of all patients treated arthroscopically between 1995 and 2010, patients treated for symptomatic discoid meniscus were identified in the hospital charts. Baseline data (demographics, previous trauma of ipsilateral knee, and associated intra-articular findings) and medium term outcome data from clinical follow-up examinations (pain, locking, snapping and instability of the operated knee) were extracted from clinical records. Telephone interviews were conducted at long term in 28 patients (31 knees). Interviews comprised clinical outcomes as well as functional outcomes as assessed by the International Knee Documentation Committee Subjective Knee Evaluation Form (IKDC). Results: All patients underwent arthroscopic partial meniscectomy. The mean follow-up time for data extracted from clinical records was 11 months (SD ± 12). A significant improvement was found for pain in 77% (p<0.001), locking in 13%, (p=0.045) and snapping in 39 % (p<0.005). The mean follow-up time of the telephone interview was 60 months (SD ± 43). Improvement from baseline was generally less after five years than after one year and functional outcomes of the IKDC indicated an abnormal function after surgery (IKDC mean= 84.5, SD ± 20). In some patients, 5 year-outcomes were even worse than their preoperative condition. Nonetheless, 74% of patients perceived their knee function as improved. Furthermore, better results were seen in patients without any associated intra-articular findings. Conclusions: Arthroscopical partial meniscectomy is an effective intervention to relieve symptoms in patients with discoid meniscus in the medium-term; however, results trend to deteriorate over time. A trend towards better outcome for patients with no associated intra-articular findings was observed.

Polimorfismos del gen Butirilcolinesterasa responsables de reacciones adversas en pacientes consumidores de “cocaína”

La butirilcolinesterasa humana (BChE; EC 3.1.1.8) es una enzima polimórfica sintetizada en el hígado y en el tejido adiposo, ampliamente distribuida en el organismo y encargada de hidrolizar algunos ésteres de colina como la procaína, ésteres alifáticos como el ácido acetilsalicílico, fármacos como la metilprednisolona, el mivacurium y la succinilcolina y drogas de uso y/o abuso como la heroína y la cocaína. Es codificada por el gen BCHE (OMIM 177400), habiéndose identificado más de 100 variantes, algunas no estudiadas plenamente, además de la forma más frecuente, llamada usual o silvestre. Diferentes polimorfismos del gen BCHE se han relacionado con la síntesis de enzimas con niveles variados de actividad catalítica. Las bases moleculares de algunas de esas variantes genéticas han sido reportadas, entre las que se encuentra las variantes Atípica (A), fluoruro-resistente del tipo 1 y 2 (F-1 y F-2), silente (S), Kalow (K), James (J) y Hammersmith (H). En este estudio, en un grupo de pacientes se aplicó el instrumento validado Lifetime Severity Index for Cocaine Use Disorder (LSI-C) para evaluar la gravedad del consumo de “cocaína” a lo largo de la vida. Además, se determinaron Polimorfismos de Nucleótido Simple (SNPs) en el gen BCHE conocidos como responsables de reacciones adversas en pacientes consumidores de “cocaína” mediante secuenciación del gen y se predijo el efecto delos SNPs sobre la función y la estructura de la proteína, mediante el uso de herramientas bio-informáticas. El instrumento LSI-C ofreció resultados en cuatro dimensiones: consumo a lo largo de la vida, consumo reciente, dependencia psicológica e intento de abandono del consumo. Los estudios de análisis molecular permitieron observar dos SNPs codificantes (cSNPs) no sinónimos en el 27.3% de la muestra, c.293A>G (p.Asp98Gly) y c.1699G>A (p.Ala567Thr), localizados en los exones 2 y 4, que corresponden, desde el punto de vista funcional, a la variante Atípica (A) [dbSNP: rs1799807] y a la variante Kalow (K) [dbSNP: rs1803274] de la enzima BChE, respectivamente. Los estudios de predicción In silico establecieron para el SNP p.Asp98Gly un carácter patogénico, mientras que para el SNP p.Ala567Thr, mostraron un comportamiento neutro. El análisis de los resultados permite proponer la existencia de una relación entre polimorfismos o variantes genéticas responsables de una baja actividad catalítica y/o baja concentración plasmática de la enzima BChE y algunas de las reacciones adversas ocurridas en pacientes consumidores de cocaína.

Caracterització i revaloració de la fracció plasmàtica de la sang de porc procedent d'escorxadors industrials

La tesi s'ha estructurat en tres apartats que, en conjunt, han de permetre determinar les possibilitats d'aprofitament dins la mateixa indústria alimentària de la fracció plasmàtica de la sang de porc generada per escorxadors que utilitzen sistemes oberts de recollida higiènica. 1. En la primera part s'analitza la composició de la sang higiènica que s'està recollint actualment i s'estudien les característiques tant físico-químiques com microbiològiques que determinen la seva qualitat. La caracterització s'ha realitzat amb sang recollida en diferents escorxadors industrials de les comarques de Girona i s'ha centrat principalment en l'estudi de la contaminació microbiològica i el nivell d'hemòlisi de la sang. S'ha fet un disseny experimental que ha permès alhora valorar l'efecte d'alguns factors sobre la qualitat de la sang: possibles diferències relacionades amb (1) la climatologia del període de l'any en el qual es fa la recollida, (2) particularitats dels escorxadors (grandària, sistemes de dessagnat, tipus, dosi i sistema de dosificació de l'anticoagulant, condicions de processament, maneig i emmagatzematge després de la recollida, etc.). Els resultats obtinguts ens permeten constatar que, en les condicions actuals, la sang que s'està recollint en els escorxadors estudiats no es pot considerar adequada per a una matèria primera de productes destinats a alimentació humana. La major part de la microbiota contaminant s'adquireix en el propi sagnador. S'ha constatat que el sistema de dessagnat en posició horitzontal podria ser una mesura útil per minimitzar la contaminació d'origen fecal o provinent de la pell de l'animal sacrificat i que la separació immediata de les fraccions en el propi escorxador també pot contribuir a reduir la contaminació. Així doncs, en el benentès que l'efectivitat pot obtenir-se del conjunt de mesures preses, més que de l'aplicació d'una sola d'elles, es suggereix la introducció d'una sèrie d'actuacions que potser permetrien reduir els nivells de contaminació que s'obtenen actualment. El tractament mecànic de la sang, el sistema d'addició d'anticoagulant, el volum i concentració de la solució anticoagulant afegida i el període d'emmagatzematge són els factors responsables de l'hemòlisi; mentre que nivells elevats de contaminació microbiològica i el tipus d'anticoagulant utilitzat deterrminen la velocitat d'increment de l'hemòlisi de sang refrigerada. S'ha constatat que quan la sang no pot ser processada immediatament i s'ha d'emmagatzemar en refrigeració és millor utilitzar citrat sòdic enlloc de polifosfat com a anticoagulant ja que l'increment d'hemòlisi es dóna més lentament. 2. El segon apartat s'ha centrat en la fracció plasmàtica de la sang. S'ha utilitzat la deshidratació per atomització com a tecnologia de conservació del plasma i s'ha fet una caracterització del producte en pols resultant des del punt de vista de composició i qualitat. A més de la contaminació microbiològica, que determina la qualitat higiènico-sanitària del producte, s'ha realitzat un estudi de les propietats funcionals que podrien fer del plasma un producte útil en la formulació d'aliments (capacitat escumant, emulsionant, gelificant). S'ha fet especial incidència en (1) determinar l'efecte del procés tecnològic de deshidratació sobre la funcionalitat del producte i (2) estudiar l'estabilitat del plasma deshidratat durant el període d'emmagatzematge. En les condicions de deshidratació per atomització aplicades no es provoca desnaturalització de la fracció proteica i s'obté un producte suficientment deshidratat, amb una aw<0,4 per permetre suposar una bona estabilitat. Algunes mostres de plasma deshidratat analitzades presenten nivells detectables de determinats residus (sulfonamides i corticosteroides). La qualitat microbiològica del producte en pols reflecteix l'elevada contaminació que contenia la matèria primera utilitzada, tot i que la deshidratació per atomització ha comportat la reducció en una unitat logarítmica de la càrrega contaminant. Els recomptes generals de microorganismes són encara preocupants i més tenint en compte que s'ha evidenciat la presència de toxines estafilocòciques en algunes mostres. L'avaluació de les propietats funcionals del producte deshidratat en relació a les que presentava el plasma líquid ens ha permès comprovar que: (1) El procés de deshidratació no ha afectat la solubilitat de les proteïnes. Això, junt amb el fet que no s'obtinguin diferències significatives en l'anàlisi calorimètrica de mostres líquides o deshidratades, permet concloure que el procés no provoca desnaturalització proteica. (2) No s'observen efectes negatius del procés tecnològic sobre la capacitat escumant ni en l'activitat emulsionant de les proteïnes plasmàtiques, dues propietats funcionals que possibiliten l'aplicació del plasma amb aquestes finalitats en l'elaboració d'alguns aliments. (3) La deshidratació tampoc perjudica de manera important les característiques dels gels que s'obtenen per escalfament, ja que els gels obtinguts a partir del plasma líquid i del plasma deshidratat presenten la mateixa capacitat de retenció d'aigua i no s'observen diferències en la microestructura de la xarxa proteica d'ambdós tipus de gel. Tanmateix, els que s'obtenen a partir del producte en pols mostren una menor resistència a la penetració. L'estudi d'estabilitat ens ha permès comprovar que la mostra de plasma deshidratat per atomització perd algunes de les seves propietats funcionals (facilitat de rehidratació, capacitat de retenció d'aigua i fermesa dels gels) si s'emmagatzema a temperatura ambient, mentre que aquestes característiques es mantenen un mínim de sis mesos quan el producte en pols es conserva a temperatura de refrigeració. 3. En l'última part, tenint en compte les conclusions derivades dels resultats dels apartats anteriors, s'han assajat tres possibles sistemes de reducció de la contaminació aplicables a la fracció plasmàtica com a pas previ a la deshidratació, per tal de millorar les característiques de qualitat microbiològica i les perspectives d'estabilitat del producte durant l'emmagatzematge. S'ha determinat l'eficàcia, i l'efecte sobre les propietats del plasma deshidratat, que poden tenir tractaments d'higienització basats en la centrifugació, la microfiltració tangencial i l'aplicació d'altes pressions. Els tractaments de bactofugació aplicats permeten reduir entre el 96 i el 98% la contaminació microbiana del plasma. Aquesta reducció s'aconsegueix tant amb un sistema discontinu com amb un sistema continu treballant a una velocitat de 12 L/h, fet que permetria adaptar el tractament de bactofugació a un procés de producció industrial. Un sistema combinat de bactofugació en continu i microfiltració tangencial permet incrementar l'eficàcia fins a un 99,9 % de reducció. Cal tenir present, però, que aquest tractament provoca també una disminució de l'extracte sec que afecta negativament les propietats funcionals del plasma líquid. Malgrat suposar una pèrdua pel que fa al rendiment, aquest efecte negatiu sobre la funcionalitat no suposaria cap inconvenient si s'utilitzés la deshidratació com a tecnologia de conservació del plasma, ja que es podria corregir l'extracte sec durant la reconstitució del producte. Caldria avaluar si la millora en la qualitat higiènico-sanitària del producte compensa o no les pèrdues que suposa aquest sistema d'higienització combinat. Amb relació als tractaments d'alta pressió, de totes les condicions de tractament assajades, les pressions de fins 450 MPa permeten obtenir plasma sense modificacions importants que impedeixin la seva deshidratació per atomització. Així doncs, les condicions de procés que s'han aplicat són pressuritzacions a 450 MPa de 15 minuts de durada. La temperatura de tractament que s'ha mostrat més eficaç en la reducció dels recomptes de microorganismes ha estat de 40ºC. Els tractaments a aquesta temperatura permeten assolir reduccions del 99,97% i disminuir en un 80% la capacitat de creixement dels microorganismes supervivents a la pressurització en relació a la que presentava la població contaminant del plasma abans del tractament. L'estudi de l'efecte d'aquest tractament (450 MPa, 15 min i 40ºC) sobre les propietats funcionals del plasma ha permès observar que la pressurització comporta una disminució en la solubilitat del producte però una millora en les propietats de superfície -estabilitat de l'escuma i activitat emulsionant- i un increment de la capacitat de retenció d'aigua i de la duresa dels gels obtinguts per escalfament. Calen més estudis per confirmar i caracteritzar aquesta millora en la funcionalitat, així com per establir si el tractament de pressurització afecta també l'estabilitat del producte durant l'emmagatzematge. De totes les tecnologies d'higienització assajades, l'alta pressió és la que permet obtenir millors resultats en el sentit de poder garantir un producte de bona qualitat microbiològica i segur, des del punt de vista sanitari i tecnològic, per a la seva utilització com a ingredient alimentari.

Land use for England and Wales: evaluation of management options to support 'good ecological status' in surface freshwaters

This paper analyses historic records of agricultural land use and management for England and Wales from 1931 and 1991 and uses export coefficient modelling to hindcast the impact of these practices on the rates of diffuse nitrogen (N) and phosphorus (P) export to water bodies for each of the major geo-climatic regions of England and Wales. Key trends indicate the importance of animal agriculture as a contributor to the total diffuse agricultural nutrient loading on waters, and the need to bring these sources under control if conditions suitable for sustaining 'Good Ecological Status' under the Water Framework Directive are to be generated. The analysis highlights the importance of measuring changes in nutrient loading in relation to the catchment-specific baseline state for different water bodies. The approach is also used to forecast the likely impact of broad regional scale scenarios on nutrient export to waters and highlights the need to take sensitive land out of production, introduce ceilings on fertilizer use and stocking densities, and controls on agricultural practice in higher risk areas where intensive agriculture is combined with a low intrinsic nutrient retention capacity, although the uncertainties associated with the modelling applied at this scale should be taken into account in the interpretation of model output. The paper advocates the need for a two-tiered approach to nutrient management, combining broad regional policies with targeted management in high risk areas at the catchment and farm scale.

Individual Differences in Amygdala and Ventromedial Prefrontal Cortex Activity are Associated with Evaluation Speed and Psychological Well-being

Using functional magnetic resonance imaging, we examined whether individual differences in amygdala activation in response to negative relative to neutral information are related to differences in the speed with which such information is evaluated, the extent to which such differences are associated with medial prefrontal cortex function, and their relationship with measures of trait anxiety and psychological well-being (PWB). Results indicated that faster judgments of negative relative to neutral information were associated with increased left and right amygdala activation. In the prefrontal cortex, faster judgment time was associated with relative decreased activation in a cluster in the ventral anterior cingulate cortex (ACC, BA 24). Furthermore, people who were slower to evaluate negative versus neutral information reported higher PWB. Importantly, higher PWB was strongly associated with increased activation in the ventral ACC for negative relative to neutral information. Individual differences in trait anxiety did not predict variation in judgment time or in amygdala or ventral ACC activity. These findings suggest that people high in PWB effectively recruit the ventral ACC when confronted with potentially aversive stimuli, manifest reduced activity in subcortical regions such as the amygdala, and appraise such information as less salient as reflected in slower evaluative speed.

Right ventromedial and dorsolateral prefrontal cortices mediate adaptive decisions under ambiguity by integrating choice utility and outcome evaluation.

The Iowa gambling task (IGT) is one of the most influential behavioral paradigms in reward-related decision making and has been, most notably, associated with ventromedial prefrontal cortex function. However, performance in the IGT relies on a complex set of cognitive subprocesses, in particular integrating information about the outcome of choices into a continuously updated decision strategy under ambiguous conditions. The complexity of the task has made it difficult for neuroimaging studies to disentangle the underlying neurocognitive processes. In this study, we used functional magnetic resonance imaging in combination with a novel adaptation of the task, which allowed us to examine separately activation associated with the moment of decision or the evaluation of decision outcomes. Importantly, using whole-brain regression analyses with individual performance, in combination with the choice/outcome history of individual subjects, we aimed to identify the neural overlap between areas that are involved in the evaluation of outcomes and in the progressive discrimination of the relative value of available choice options, thus mapping the two fundamental cognitive processes that lead to adaptive decision making. We show that activation in right ventromedial and dorsolateral prefrontal cortex was predictive of adaptive performance, in both discriminating disadvantageous from advantageous decisions and confirming negative decision outcomes. We propose that these two prefrontal areas mediate shifting away from disadvantageous choices through their sensitivity to accumulating negative outcomes. These findings provide functional evidence of the underlying processes by which these prefrontal subregions drive adaptive choice in the task, namely through contingency-sensitive outcome evaluation.

Plant species and functional group effects on abiotic and microbial soil properties and plant-soil feedback responses in two grasslands

1 Plant species differ in their capacity to influence soil organic matter, soil nutrient availability and the composition of soil microbial communities. Their influences on soil properties result in net positive or negative feedback effects, which influence plant performance and plant community composition. 2 For two grassland systems, one on a sandy soil in the Netherlands and one on a chalk soil in the United Kingdom, we investigated how individual plant species grown in monocultures changed abiotic and biotic soil conditions. Then, we determined feedback effects of these soils to plants of the same or different species. Feedback effects were analysed at the level of plant species and plant taxonomic groups (grasses vs. forbs). 3 In the sandy soils, plant species differed in their effects on soil chemical properties, in particular potassium levels, but PLFA (phospholipid fatty acid) signatures of the soil microbial community did not differ between plant species. The effects of soil chemical properties were even greater when grasses and forbs were compared, especially because potassium levels were lower in grass monocultures. 4 In the chalk soil, there were no effects of plant species on soil chemical properties, but PLFA profiles differed significantly between soils from different monocultures. PLFA profiles differed between species, rather than between grasses and forbs. 5 In the feedback experiment, all plant species in sandy soils grew less vigorously in soils conditioned by grasses than in soils conditioned by forbs. These effects correlated significantly with soil chemical properties. None of the seven plant species showed significant differences between performance in soil conditioned by the same vs. other plant species. 6 In the chalk soil, Sanguisorba minor and in particular Briza media performed best in soil collected from conspecifics, while Bromus erectus performed best in soil from heterospecifics. There was no distinctive pattern between soils collected from forb and grass monocultures, and plant performance could not be related to soil chemical properties or PLFA signatures. 7 Our study shows that mechanisms of plant-soil feedback can depend on plant species, plant taxonomic (or functional) groups and site-specific differences in abiotic and biotic soil properties. Understanding how plant species can influence their rhizosphere, and how other plant species respond to these changes, will greatly enhance our understanding of the functioning and stability of ecosystems.