ALBERT

Beschreibung: Learning and memory allow animals to adjust their foraging strategies through experience. Despite the known impact of temperature on many aspects of the behavioral ecology of animals, memory retention in the face of realistic thermal stress has seldom been assessed. In the laboratory, we studied the behavioral expression of an egg parasitoid’s ( Trissolcus basalis ) memory when exposed to thermal stress that could be encountered in nature. We hypothesized that thermal stress would disrupt memory consolidation and/or modify the optimality of memory retention, thus affecting patch time allocation strategies. Memory consolidation was resilient to 1h of thermal stress following an unrewarded experience (learning) on a patch of host-associated infochemicals. Neither high (40 °C) or low (10 °C) thermal stress changed the intensity of the experienced wasps’ behavioral response relative to those held at a moderate temperature (25 °C). Next, we investigated how temperature stress could affect the parasitoids’ memory retention ("forgetting"). When kept at a constant moderate temperature after learning, residence times of wasps retested on host cues increased relative to controls (naïve wasps) over a period of 4 days as they presumably "forgot." However, both hot and cool daily temperature cycles prevented forgetting; the residence times of retested experienced wasps in these treatments did not change relative to controls over time. We discuss to what extent this may be an adaptive response by the parasitoids versus a physiological constraint imposed by temperature. Our findings contribute to an understanding of the impact of thermal stress on foraging strategies that involve learning and memory.

Beschreibung: Petrological data have been acquired on natural trachytes from the Chaîne des Puys, French Massif Central, and on experimental products from phase equilibria to (1) constrain the storage conditions of trachytic magmas that lead to explosive eruptions (dome destructions as block-and-ash flows or pumice-and-ash flows) and (2) provide phase relationships and chemical compositions for differentiated alkaline liquids in an intraplate continental context. Phase assemblages, proportions, and compositions have been determined on six trachytes with SiO 2 contents varying from 62 to 69 wt % and alkali contents of 10·5–12·0 wt %. The samples contain up to 30% of phenocrysts, mainly consisting of feldspar (15–17%; plagioclase and/or alkali-feldspar), biotite (2–6%; except in the most SiO 2 -poor sample), Fe–Ti oxides (1–3%) ± amphibole (〈5%), ± clinopyroxene (~1%). All samples have apatite and zircon as minor phases and titanite was found in one sample. Pristine glasses (melt inclusions or residual glasses) in pumice from explosive events are trachytic to rhyolitic (65–73 wt % SiO 2 and 10·5–13·0 wt % alkali). H 2 O dissolved in melt inclusions and the biotite + alkali feldspar + magnetite hygrobarometer both suggest pre-eruptive H 2 O contents up to 8 wt %. These are so far the highest H 2 O contents ever reported for alkaline liquids in an intraplate continental context. Melt inclusions also contain ~3400 ppm chlorine, ~700 ppm fluorine, and ~300 ppm sulphur. Crystallization experiments on the six trachytes were performed between 200 and 400 MPa, 700 and 900°C, at H 2 O saturation, and oxygen fugacity of NNO ± 1. A comparison between the natural and experimental phase assemblage, proportions, and composition suggests magma storage conditions at a pressure of 300–350 MPa (~10–12 km deep), melt H 2 O content ~8 wt % (close to saturation), an oxygen fugacity close to NNO ~0·5, and temperatures increasing from 700 to 825°C with decreasing bulk SiO 2 content of the trachyte. The high H 2 O contents of the trachytes show that wet conditions may prevail during the differentiation of continental alkaline series. Regardless of the size of the magma reservoir assumed to have fed the trachyte eruptions, calculation of thermal relaxation timescales indicates that the tapped magma reservoir(s) are likely to be still partially molten. The four northernmost edifices may correspond to a single large reservoir with a lateral extent of up to 10 km, which could be possibly reactivated in weeks to months if intercepted by new rising mafic magma batches.

Beschreibung: During Drosophila oogenesis, transposable element (TE) repression involves the Piwi-interacting RNA (piRNA) pathway which ensures genome integrity for the next generation. We developed a transgenic model to study repression of the Idefix retrotransposon in the germline. Using a candidate gene KD-approach, we identified differences in the spatio-temporal requirements of the piRNA pathway components for piRNA-mediated silencing. Some of them (Aub, Vasa, Spn-E) are necessary in very early stages of oogenesis within the germarium and appear to be less important for efficient TE silencing thereafter. Others (Piwi, Ago3, Mael) are required at all stages of oogenesis. Moreover, during early oogenesis, in the dividing cysts within the germarium, Idefix anti-sense transgenes escape host control, and this is associated with very low piwi expression. Silencing of P -element-based transgenes is also strongly weakened in these cysts. This region, termed the ‘Piwiless pocket’ or Pilp, may ensure that new TE insertions occur and are transmitted to the next generation, thereby contributing to genome dynamics. In contrast, piRNA-mediated silencing is strong in germline stem cells in which TE mobilization is tightly repressed ensuring the continued production of viable germline cysts.

Beschreibung: Sensitive clays are known for producing retrogressive landslides, also called spread or flowslides. The key characteristics associated with the occurrence of these landslides on a sensitive clay slope must be assessed, and the potential retrogressive distance must be evaluated. Common risk analysis methods include empirical methods for estimating the distance of potential retrogression, analytical limit equilibrium methods, numerical modelling methods using the strength reduction technique, and the integration of a progressive failure mechanism into numerical methods. Methods developed for zoning purposes in Norway and Quebec provide conservative results in most cases, even if they don’t cover the worst cases scenario. A flowslide can be partially analysed using analytical limit equilibrium methods and numerical methods having strength reduction factor tools. Numerical modelling of progressive failure mechanisms using numerical methods can define the critical parameters of spread-type landslides, such as critical unloading and the retrogression distance of the failure. Continuous improvements to the large-deformation numerical modeling approach allow its application to all types of sensitive clay landslides.

Beschreibung: Recent studies indicate that the timing of food intake can significantly affect metabolism and weight management. Workers operating at atypical times of the 24-h day are at risk of disturbed feeding patterns. Given the increased risk of weight gain, obesity and metabolic syndrome in shift working populations, further research is required to understand whether their eating behavior could contribute to these increased metabolic risks. The objective of this study was to characterize the dietary patterns of police officers across different types of shifts in their natural environments. Thirty-one police officers (six women; aged 32.1 ± 5.4 years, mean ± SD) from the province of Quebec, Canada, participated in a 28- to 35-day study, comprising 9- to 12-h morning, evening, and night shifts alternating with rest days. Sleep and work patterns were recorded with actigraphy and diaries. For at least 24 h during each type of work day and rest day, participants logged nutrient intake by timestamped photographs on smartphones. Macronutrient composition and caloric content were estimated by registered dieticians using the Nutrition Data System for Research database. Data were analyzed with linear mixed effects models and circular ANOVA. More calories were consumed relative to individual metabolic requirements on rest days than both evening- and night-shift days (p = 0.001), largely sourced from increased fat (p = 0.004) and carbohydrate (trend, p = 0.064) intake. Regardless, the proportions of calories from carbohydrates, fat, and protein did not differ significantly between days. More calories were consumed during the night, between 2300 h and 0600 h, on night-shift days than any other days (p 〈 0.001). Caloric intake occurred significantly later for night-shift days (2308 h ± 0114 h, circular mean ± SD) than for rest days (1525 h ± 0029 h; p 〈 0.01) and was dispersed across a longer eating window (13.9 h ± 3.1 h vs. 11.3 h ± 1.8 h, mean ± SD). As macronutrient proportions were similar and caloric intake was lower, the finding of later meals times on night-shift days versus rest days is consistent with emerging hypotheses that implicate the biological timing of food intake—rather than its quantity or composition—as the differentiating dietary factor in shift worker health.

Beschreibung: Fatty acids (FAs) are crucial in child growth and development. In Uganda, antiretroviral therapy (ART) has drastically reduced perinatal human immunodeficiency virus (HIV) infection of infants, however, the interplay of FAs, ART, and HIV in relation to child growth is not well understood. To investigate this, serum was collected from 240 children between 6–10 years old in Uganda and analyzed for FAs using gas-chromatography mass-spectrometry. HIV status and anthropometric measurements were taken, and relationships with FAs were assessed. No significant differences in growth parameters or serum FAs were found between HIV uninfected children with and without exposure to ART. HIV positive children had significantly lower height-for-age-z-scores (HAZ) than uninfected children (p 〈 0.001). HIV-positive children had higher arachidonic acid than uninfected children (p = 0.003). Total omega-6 FAs were significantly associated with HAZ regardless of HIV status (p = 0.035). Mean total omega-3 FAs (2.90%) were low in this population compared to other cohorts in Africa. These results provide reference serum FA values for 6–10-year-old children in Uganda and may be used to inform lipid supplementation programs to promote child growth. Future studies should investigate the relationships between child growth trajectories in relation to HIV status and serum FAs.

Beschreibung: An impact of vitamin D in neurocognitive function has been theorized but it remains unknown whether vitamin-D insufficiency (VDI) is associated with worse socio-emotional adjustment (SEA) in vulnerable early school-aged children. This study examines the thesis that deficits in SEA are related to VDI using longitudinal data from 254 children that are perinatally HIV-infected (PHIV), exposed-uninfected (HEU), or unexposed-uninfected (HUU). In utero/peripartum antiretroviral (IPA) exposure was established per medical record documentation of biological mother’s ART regimen in pregnancy. Four caregiver-reported age- and sex-standardized measures of SEA were obtained at months 0, 6, and 12 for dependent children aged 6–10 years: externalizing problems (EPC), internalizing problems (IPC), behavioral symptoms index (BSI), and adaptive skills index (ASI). VDI was highly prevalent (74%, n = 188), and its association with change in SEA measures over 12 months varied by HIV-status (VDI*HIV, all p-values 〈 0.03). There was further variation in relationship of vitamin-D to SEA by IPA among PHIV (for ASI, BSI, and EPC, vitamin-D*IPA, p-value ≤ 0.01) and HEU (for BSI and EPC, vitamin-D*IPA, p-value ≤ 0.04). Among HUU, BSI (β = −0.32, 95% CI: −0.50, −0.13), IPC (β = −0.28, 95% CI: −0.47, −0.09), and EPC (β = −0.20, 95% CI: −0.37, −0.02) all declined moderately per quartile increment in VD. Among PHIV, on the one hand higher vitamin D predicted ASI gains (moderate vs. low VD, β = 0.52, p = 0.002), but this protective association was absent for BSI, EPC, and IPC (β = 0.36–0.77, p 〈 0.05). In absence of IPA-exposure, increasing vitamin-D predicted declines in BSI and EPC (moderate vs. low Vitamin D, β = −0.56 to −0.71, p ≤ 0.02) among HEU. However, given IPA exposure among HEU, higher VDI predicted moderate elevation in BSI (β = 0.39, 95% CI: 0.00, 0.78) and IPC (β = 0.48, 95% CI: 0.05, 0.92). Interaction between VD and IPA exposure for SEA outcomes among HEU and PHIV children warrants further investigation. The vitamin-D associated SEA improvement among HUU and HEU without IPA exposure suggests vitamin-D supplementation may remediate behavioral and adaptive deficits in this groups.

Beschreibung: Human metapneumovirus (HMPV) is an important human pathogen that, along with respiratory syncytial virus (RSV), is a major cause of respiratory tract infections in young infants. Development of an effective vaccine against Pneumoviruses has proven to be particularly difficult; despite over 50 years of research in this field, no vaccine against HMPV or RSV is currently available. Recombinant chimeric viruses expressing antigens of other viruses can be generated by reverse genetics and used for simultaneous immunization against more than one pathogen. This approach can result in the development of promising vaccine candidates against HMPV, and several studies have indeed validated viral vectors expressing HMPV antigens. In this review, we summarize current efforts in generating recombinant chimeric vaccines against HMPV, and we discuss their potential optimization based on the correspondence with RSV studies.

Beschreibung: In 1947, Zika virus (ZIKV), a mosquito-borne flavivirus was identified in Uganda and subsequently spread to Asia and the Pacific regions. In 2015, it was introduced in Brazil causing an important social and sanitary alarm due to its increased virulence and rapid dissemination. Importantly, ZIKV infections have been associated with severe neurological complications such as Guillain–Barré syndrome and microcephaly in fetuses and newborns. Although enormous efforts were made by investigators in the development of effective countermeasures against ZIKV, there is still no approved specific antiviral drug for the treatment of ZIKV infections. Herein, we review several anti ZIKV candidates including drugs targeting both the virus (structural proteins and enzymes) and cellular elements.