Dynamics of macronutrient self-medication and illness-induced anorexia in virally infected insects

Some animals change their feeding behaviour when infected with parasites, seeking out substances that enhance their ability to overcome infection. This 'self-medication' is typically considered to involve the consumption of toxins, minerals or secondary compounds. However, recent studies have shown that macronutrients can influence the immune response and that pathogen-challenged individuals can self-medicate by choosing a diet rich in protein and low in carbohydrates. Infected individuals might also reduce food intake when infected (i.e. illness-induced anorexia). Here, we examine macronutrient self-medication and illness-induced anorexia in caterpillars of the African armyworm (Spodoptera exempta) by asking how individuals change their feeding decisions over the time course of infection with a baculovirus. We measured self-medication behaviour across several full-sib families to evaluate the plasticity of diet choice and underlying genetic variation. Larvae restricted to diets high in protein (P) and low in carbohydrate (C) were more likely to survive a virus challenge than those restricted to diets with a low P : C ratio. When allowed free choice, virus-challenged individuals chose a higher protein diet than controls. Individuals challenged with either a lethal or sublethal dose of virus increased the P : C ratio of their chosen diets. This was mostly due to a sharp decline in carbohydrate intake, rather than an increased intake of protein, reducing overall food intake, consistent with an illness-induced anorexic response. Over time the P : C ratio of the diet decreased until it matched that of controls. Our study provides the clearest evidence yet for dietary self-medication using macronutrients and shows that the temporal dynamics of feeding behaviour depends on the severity and stage of the infection. The strikingly similar behaviour shown by different families suggests that self-medication is phenotypically plastic and not a consequence of genetically based differences in diet choice between families. © 2013 British Ecological Society.

The Prevalence of Age-Related Macular Degeneration in Alzheimer's Disease

BACKGROUND:
Age-related macular degeneration (AMD) and Alzheimer's disease (AD) share several features, including the presence of extracellular abnormal deposits associated with neuronal degeneration, drusen, and plaques, respectively. Investigation of any association of AMD and specifically AD is worthwhile but has rarely been done.
OBJECTIVES:
The aim of this study was to determine the prevalence of AMD in subjects with AD in comparison with an age-matched cognitively normal cohort.
METHODS:
Cases were defined as those diagnosed with AD using standardized criteria as part of their clinical care, while controls were cognitively intact individuals aged 65 years or more. Dilated retinal photographs were taken, and a range of potentially confounding factors measured including APOE genotype. AMD features were recorded and AMD grades given.
RESULTS:
Data was collected on 322 controls and 258 cases. While AMD was associated with AD, and the proportion of cases of advanced AMD in AD cases was twice that of controls, when corrected the association was lost. AD was associated with age, the presence of an APOE allele, and smoking, while being 'generally unwell recently' was associated with a reduced risk of AD.
CONCLUSION:
AD and AMD are both associated with age, but our study does not find evidence they are associated with each other. However the retina offers an opportunity to non-invasively image neuronal tissue, and more sophisticated imaging techniques may shed light on ocular biomarkers of AD.

A randomized, controlled trial of an intervention promoting cataract surgery acceptance in Rural China:The Guangzhou uptake of surgery trial (GUSTO)

PURPOSE. To evaluate an educational intervention promoting acceptance of cataract surgery in rural China using a randomized controlled design. METHODS. Patients aged 50 years or older with presenting visual acuity (PVA) less than 6/18 in one or both eyes due to cataract were recruited from 26 screening sessions (13 intervention, 13 control) conducted by five rural hospitals in Guangdong, China. At intervention sessions, subjects were shown a 5- minute informational video, and counseled about cataract, surgery, and surgical cost. During screening, all subjects answered questionnaires on knowledge and attitudes about cataract, their finances, and transportation, and were referred for definitive examination if eligible. Study outcomes were acceptance of surgery (principal outcome) and hospital followup. RESULTS. Subjects in the intervention group were younger than controls (P = 0.01), but the groups did not otherwise differ. Among 212 intervention patients and 222 controls, no differences in knowledge and attitude regarding cataract were found. Surgery was accepted by 31.1% of intervention patients and 34.2% of controls (P > 0.50). Predictors of acceptance included younger age, worse logMAR PVA, knowing that cataract can be treated surgically only, greater anticipated loss in income from hospitalization, and greater house floor space per person. Membership in the intervention group was not associated with accepting surgery (odds ratio [OR]=1.11, 95% confidence interval [CI] 0.67-1.84) or hospital follow-up (OR= 1.03, 95% CI = 0.63-1.67). CONCLUSIONS. Educational interventions that successfully impart the knowledge that cataract can be only treated surgically may be more effective in increasing uptake in this setting. © 2012 The Association for Research in Vision and Ophthalmology, Inc.

Microbiological Profile of Aggressive Periodontitis in a Sudanese Population

Background: Several bacterial species have been identified as being associated with aggressive periodontitis (AgP) notably Aggregatibacter actinomycetemcomitans (Aa) and Porphyromonas gingivalis (Pg). There are limited data on bacterial associations with AgP in African populations. Objective: To investigate possible associations between specific bacteria and AgP in a Sudanese population. Methods: Subgingival plaque samples were collected from 93 (20 male, 73 female) Sudanese patients diagnosed with AgP and from 72 (23 male, 48 female) periodontally healthy Sudanese controls. Quantitative PCR was used to identify Aa, Pg, Treponema denticola (Td) and Fusobacterium nucleatum (Fn). The prevalence of these bacterial species was compared using Chi-square analysis. Odds ratios (OR) were calculated using standard methods. Results: The cases with AgP were well matched in age with the controls: 24.8 (SD 5.1) compared with 23.5 (SD 3.7) years, p=0.07. There was a significantly higher prevalence of Pg in AgP (73%) than in the controls (33%), p<0.0001. The OR for Pg to be associated with AgP was 5.44 (95% confidence intervals 2.78-10.64). In 26 (38%) of the AgP cases positive for Pg there were low levels of this bacterium (<100 copies). Both Td and Fn were identified in virtually all (>95%) the plaque samples studied from both AgP and controls. Aa was the least frequently identified species and was present in only 28% of AgP and 18% of controls, p=0.14. The OR for Aa to be associated with AgP was slightly increased at 1.76 (95% CI 0.83-3.74), however, this was not significant (p=0.14). Conclusion: In the Sudanese subjects studied Pg but not Aa was associated with AgP. There were very low levels of Pg in many of the plaque samples from AgP.

SHORT-TERM EFFECTS OF SALINITY ON SOME PHYSIOLOGICAL PARAMETERS OF YOUNG OLIVE TREES OF ARBEQUINA, COBRANÇOSA AND GALEGA VARIETIES

SHORT-TERM EFFECTS OF SALINITY ON SOME PHYSIOLOGICAL PARAMETERS OF YOUNG OLIVE TREES OF ARBEQUINA, COBRANÇOSA AND GALEGA VARIETIES Ana Elisa Rato1,4, Renato Coelho1, Margarida Vaz1, Teresa Carola2, Dália Barbosa2, Nádia Silva1, José dos Santos2, Lourenço Machado2, João Godinho2, Luzia Ruas2, Margarida Barradas2, Hernani Pereira2, Sara Porfírio4 1 ICAAM, Universidade de Évora, Apartado 94, 7002-554 Évora, Portugal 2 Master students, Universidade de Évora, Apartado 94, 7002-554 Évora, Portugal 3 Ph.D. student, Universidade de Évora, Apartado 94, 7002-554 Évora, Portugal 4 aerato@uevora.pt Due to the desertification in some regions, the interest in plant’s tolerance to salinity has been increasing, as this response is determining for plant survival in stress conditions. This work reports the investigation of tolerance to salt in two year-old olive trees (Olea europaea L.) of three varieties, Arbequina, Cobrançosa and Galega vulgar. Plants were grown in 10 L plastic pots containing approximately 9 Kg of a sandy granitic soil, on a greenhouse. For 3 months (from the beginning of February to the end of April 2012), they were subjected to three levels of salinity in the irrigation water, 0 mM, 80 mM and 200 mM NaCl (6 plants per salinity level in a total of 18 plants of each variety),. Stomatal conductance (gs) and relative leaf chlorophyll content were assessed on each plant in February, March and April. Mid-day leaf water potential () and soil salinity were measured at the end of the experiment (April). On average, concerning all treatments and dates of determination, stomatal conductance of Arbequina and Galega vulgar was quite similar, around 40 mmol m-2 s-1, but Cobrançosa had a value of gs 36% higher, almost 50% higher (61 mmol m-2 s-1) when compared with the controls (0 mM salt) of the other two varieties. In percentage of controls, there was little difference in gs between varieties and between salinities during February and March. In contrast, in April, after about 90 days of exposure to salt, there was a clear decrease in gs with salt irrigation, proportional to salt concentration. Compared with controls, plants irrigated with 200 mM salt showed around 80% (Arbequina) or 85% (Cobrançosa and Galega vulgar) decrease in gs. Chlorophyll content of leaves showed less than 5% difference between varieties on the average of all treatments and dates of determination. During the course of this experiment, the salinity levels used did not show any relevant effect on chlorophyll content. Overall, at the end of the experimental period (April), leaf water potential () at midday was significantly higher in Cobrançosa (-1,4 MPa) than in Galega vulgar (-1,7 MPa) or Arbequina (-1,8 MPa), and salt decreased  of control plants (-1,25 MPa) by an average 30% (with 80 mM) and 65% (with 200 mM). At the end of the experiment, salinity in the soil irrigated with 0 mM, 80 mM or 200 mM NaCl was, on average of all varieties, 0,2 mS, 1,0 mS or 2,0 mS, respectively. Soil salinity was quite similar in Arbequina and Galega vulgar but about 35% lower in the pots of Cobrançosa, on average of all salt-irrigation levels. Plants of Cobrançosa had higher stomatal conductance, however they showed higher water potential and lower salinity in the soil. These apparently contradictory results seem to suggest that Cobrançosa responds to salt differently from the other two varieties. This issue needs further investigation.

Salinity-induced effects on transpiration rate, stomatal conductance and leaf area of three olive (Olea europaea L.) varieties

Transpiration of two year-old olive trees of three different varieties, Arbequina, Cobrançosa and Galega (18 trees per variety), irrigated with three levels of salt (0, 80 or 200 mM NaCl) for about 90 days, was measured by a gravimetric method. To determine leaf area, each tree was photographed from the side against a white background and the total area of each projected image was determined with ImageJ software. To calibrate these area determinations, one tree of each variety was subsequently stripped of all its leaves and its total leaf area was accurately measured. A correlation was then obtained between the area on the photograph of this particular tree and the total area of the detached leaves of the same tree. Using the leaf area determined by this procedure, transpiration rates of the trees could be calculated. Knowing leaf and air temperatures and RH, it was possible to determine the difference in molar fraction of water between the leaf and the air. Using this and the values of the transpiration rate, stomatal conductance could be calculated (gs calc) and compared with the conductance measured on the same trees with a porometer (gs). Actual leaf area of a plant was 1,40 (Arbequina), 1,42 (Cobrançosa) or 1,24 (Galega) times the area measured with ImageJ on the photograph of the same plant. Leaf area of the trees, on average of all salt irrigations, was significantly higher on Arbequina (0,187 m2) then on the other two varieties (0,138 m2 or 0,148 m2, for Cobrançosa or Galega, respectively), but did not differ significantly in percentage of controls (0 salt). On average of all three varieties, leaf area was also higher on plants irrigated without salt (0,181 m2) than on plants exposed to 80 or 200 mM NaCl (0,152 m2 or 0,140 m2, respectively), which did not differ between them. The same significant difference was observed when leaf area was expressed as percentage of controls. Transpiration rate was significantly higher on Cobrançosa (1,17 mmol m-2 s-1), on average of all treatments, but there were no significant differences between Arbequina (1,08 mmol m-2 s-1) and Galega (0,82 mmol m-2 s-1). In percentage of controls, there were no significant differences between varieties. Salt reduced significantly the transpiration rate in all varieties, both the actual and percentual values, to about 50% or 30% of controls when exposed to 80 mM or 200 mM NaCl, respectively. Stomatal conductance (gs), assessed by porometry, was significantly higher in control plants, mainly in Cobrançosa (102 mmol m-2 s-1), then in Arbequina (77 mmol m-2 s-1) and the lower values were found in Galega (51 mmol m-2 s-1). Salt reduced gs, on average of the three varieties to 30% or 10% of controls on exposure to 80 mM or 200 mM NaCl, respectively. Calculated (gs calc) and measured (gs) values of stomatal conductance showed a close relation between them (0,967, R2 = 0,837) which indicates this non-destructive method to determine whole-plant leaf area to be reasonably accurate.

Lyophilisation of influenza, rabies and Marburg lentiviral pseudotype viruses for the development and distribution of a neutralisation-assay based diagnostic kit

Pseudotype viruses (PVs) are chimeric, replication-deficient virions that mimic wild-type virus entry mechanisms and can be safely employed in neutralisation assays, bypassing the need for high biosafety requirements and performing comparably to established serological assays. However, PV supernatant necessitates -80°C long-term storage and cold-chain maintenance during transport, which limits the scope of dissemination and application throughout resource-limited laboratories. We therefore investigated the effects of lyophilisation on influenza, rabies and Marburg PV stability, with a view to developing a pseudotype virus neutralisation assay (PVNA) based kit suitable for affordable global distribution. Infectivity of each PV was calculated after lyophilisation and immediate reconstitution, as well as subsequent to incubation of freeze-dried pellets at varying temperatures, humidities and timepoints. Integrity of glycoprotein structure following treatment was also assessed by employing lyophilised PVs in downstream PVNAs. In the presence of 0.5M sucrose-PBS cryoprotectant, each freeze-dried pseudotype was stably stored for 4 weeks at up to 37°C and could be neutralised to the same potency as unlyophilised PVs when employed in PVNAs. These results confirm the viability of a freeze-dried PVNA-based kit, which could significantly facilitate low-cost serology for a wide portfolio of emerging infectious viruses.

Multivariate Moments Expansion Density: Application of the Dynamic Equicorrelation Model

In this study, we propose a new semi-nonparametric (SNP) density model for describing the density of portfolio returns. This distribution, which we refer to as the multivariate moments expansion (MME), admits any non-Gaussian (multivariate) distribution as its basis because it is specified directly in terms of the basis density’s moments. To obtain the expansion of the Gaussian density, the MME is a reformulation of the multivariate Gram-Charlier (MGC), but the MME is much simpler and tractable than the MGC when positive transformations are used to produce well-defined densities. As an empirical application, we extend the dynamic conditional equicorrelation (DECO) model to an SNP framework using the MME. The resulting model is parameterized in a feasible manner to admit two-stage consistent estimation and it represents the DECO as well as the salient non-Gaussian features of portfolio return distributions. The in- and out-of-sample performance of a MME-DECO model of a portfolio of 10 assets demonstrate that it can be a useful tool for risk management purposes.

Impact of a price-maker pumped storage hydro unit on the integration of wind energy in power systems

The increasing integration of larger amounts of wind energy into power systems raises important operational issues, such as the balance between power generation and demand. The pumped storage hydro (PSH) units are one possible solution to mitigate this problem, once they can store the excess of energy in the periods of higher generation and lower demand. However, the behaviour of a PSH unit may differ considerably from the expected in terms of wind power integration when it operates in a liberalized electricity market under a price-maker context. In this regard, this paper models and computes the optimal PSH weekly scheduling in a price-taker and price-maker scenarios, either when the PSH unit operates in standalone and integrated in a portfolio of other generation assets. Results show that the price-maker standalone PSH will integrate less wind power in comparison with the price-taker situation. Moreover, when the PSH unit is integrated in a portfolio with a base load power plant, the role of the price elasticity of demand may completely change the operational profile of the PSH unit. (C) 2014 Elsevier Ltd. All rights reserved.

Impact of mobile app user acquisition on managerial decisions: Evidence from empirical experiment

In this research we conducted a mixed research, using qualitative and quantitative analysis to study the relationship and impact between mobile advertisement and mobile app user acquisition and the conclusions companies can derive from it. Data was gathered from management of mobile advertisement campaigns of a portfolio of three different mobile apps. We found that a number of implications can be extracted from this intersection, namely to product development, internationalisation and management of marketing budget. We propose further research on alternative app users sources, impact of revenue on apps and exploitation of product segments: wearable technology and Internet of Things.

Investigating the potential of thecamoebians (testate amoebae) as bio-indicators of impact of oil sands mining operations on freshwater environments in Northeastern Alberta, Canada

Thecamoebian (testate amoeba) species diversity and assemblages in reclamation wetlands and lakes in northeastern Alberta respond to chemical and physical parameters associated with oil sands extraction. Ecosystems more impacted by OSPM (oil sands process-affected material) contain sparse, low-diversity populations dominated by centropyxid taxa and Arcella vulgaris. More abundant and diverse thecamoebian populations rich in difflugiid species characterize environments with lower OSPM concentrations. These shelled protists respond quickly to environmental change, allowing year-to-year variations in OSPM impact to be recorded. Their fossil record thus provides corporations with interests in the Athabasca Oil Sands with a potential means of measuring the progression of highlyimpacted aquatic environments to more natural wetlands. Development of this metric required investigation of controls on their fossil assemblage (e.g. seasonal variability, fossilization potential) and their biogeographic distribution, not only in the constructed lakes and wetlands on the oil sands leases, but also in natural environments across Alberta.

Niagara River and Falls from Lake Erie to Lake Ontario : a series of one hundred and fifty-three original etchings (1886)

A portfolio of 50 folio and 103 vignette etchings, printed on fine china paper, which has been pressed into a sturdy hand-made paper. The plates were printed by J.H. Daniels of Boston in black, brown, sepia or blue ink. All prints are dated, numbered, and signed or initialed in the plate by Sangster, and the folio prints have pencil signatures. Vol. 1. Vignettes (nos. 1-53) -- vol. 2. Vignettes (nos. 54-103) -- vol. 3. Plates (vol. 1 and 2, nos. 1-50).

Niagara River and Falls from Lake Erie to Lake Ontario : a series of one hundred and fifty-three original etchings (1886) Vol.2

A portfolio of 50 folio and 103 vignette etchings, printed on fine china paper, which has been pressed into a sturdy hand-made paper. The plates were printed by J.H. Daniels of Boston in black, brown, sepia or blue ink. All prints are dated, numbered, and signed or initialed in the plate by Sangster, and the folio prints have pencil signatures. Vol. 1. Vignettes (nos. 1-53) -- vol. 2. Vignettes (nos. 54-103) -- vol. 3. Plates (vol. 1 and 2, nos. 1-50).

Niagara River and Falls from Lake Erie to Lake Ontario : a series of one hundred and fifty-three original etchings (1886) Vol. 3

A portfolio of 50 folio and 103 vignette etchings, printed on fine china paper, which has been pressed into a sturdy hand-made paper. The plates were printed by J.H. Daniels of Boston in black, brown, sepia or blue ink. All prints are dated, numbered, and signed or initialed in the plate by Sangster, and the folio prints have pencil signatures. Vol. 1. Vignettes (nos. 1-53) -- vol. 2. Vignettes (nos. 54-103) -- vol. 3. Plates (vol. 1 and 2, nos. 1-50).

Sequential Machine learning Approaches for Portfolio Management

Cette thèse envisage un ensemble de méthodes permettant aux algorithmes d'apprentissage statistique de mieux traiter la nature séquentielle des problèmes de gestion de portefeuilles financiers. Nous débutons par une considération du problème général de la composition d'algorithmes d'apprentissage devant gérer des tâches séquentielles, en particulier celui de la mise-à-jour efficace des ensembles d'apprentissage dans un cadre de validation séquentielle. Nous énumérons les desiderata que des primitives de composition doivent satisfaire, et faisons ressortir la difficulté de les atteindre de façon rigoureuse et efficace. Nous poursuivons en présentant un ensemble d'algorithmes qui atteignent ces objectifs et présentons une étude de cas d'un système complexe de prise de décision financière utilisant ces techniques. Nous décrivons ensuite une méthode générale permettant de transformer un problème de décision séquentielle non-Markovien en un problème d'apprentissage supervisé en employant un algorithme de recherche basé sur les K meilleurs chemins. Nous traitons d'une application en gestion de portefeuille où nous entraînons un algorithme d'apprentissage à optimiser directement un ratio de Sharpe (ou autre critère non-additif incorporant une aversion au risque). Nous illustrons l'approche par une étude expérimentale approfondie, proposant une architecture de réseaux de neurones spécialisée à la gestion de portefeuille et la comparant à plusieurs alternatives. Finalement, nous introduisons une représentation fonctionnelle de séries chronologiques permettant à des prévisions d'être effectuées sur un horizon variable, tout en utilisant un ensemble informationnel révélé de manière progressive. L'approche est basée sur l'utilisation des processus Gaussiens, lesquels fournissent une matrice de covariance complète entre tous les points pour lesquels une prévision est demandée. Cette information est utilisée à bon escient par un algorithme qui transige activement des écarts de cours (price spreads) entre des contrats à terme sur commodités. L'approche proposée produit, hors échantillon, un rendement ajusté pour le risque significatif, après frais de transactions, sur un portefeuille de 30 actifs.