Numerical model for solar thermal collectors and thermal energy storages based on phase change slurry

The efficiency of conventional solar thermal collectors and related thermal energy storages is often reduced by the requirement for high irradiation levels and the heat losses due to the relatively high temperature of the heat transfer fluid. In order to overcome those limitations, a solar thermal system capable of working at low temperatures through the exploitation of latent heat storage is presented in this paper. The proposed system was based on a novel heat transfer fluid and storage media, composed by a mixture of water and micro-encapsulated phase change material (PCM), named Phase Change Slurry (PCS). This paper introduces a numerical model capable of accurately describe the physical process and the dynamics of the proposed technology (collector, thermal energy storage and control logics). Results were validated by means of experimental tests and a long-term monitoring on a real full-scale prototype. Furthermore, experimental tests were performed to carry out the actual PCS thermo-dynamical properties that are strongly dependent on the concentration of micro-capsules in the heat transfer fluid

Recent and subfossil diatom assemblages as indicators of environmental change (including fish introduction) in a high-mountain lake

We investigated modern-littoral and subfossil sediment-core diatoms in the shallow (max depth 6.4 m) high-mountain Lake Balma in the Orsiera Rocciavrè Nature Park (Italian Western Alps). Our study provided evidence that might be related to the response of diatom assemblages to fish introduction, in particular the decreasing of the nutrient-enrichment sensitive low-profile life-form/ecological guild and the increase in species known to react positively to the augmented nutrient availability due to fish excretions (e.g., Fragilaria nanana, Pseudostaurosira brevistriata, Staurosirella neopinnata). We are, however, aware that some of these effects could as well have been caused by pastures and cattle watering, and by increased temperatures due to global warming, and we acknowledge the typical complex-interaction pattern among different stressors. High-mountain lakes are ‘‘early warning systems’’ for the whole alpine system and can contribute valuable information also on the interactions between environmental global changes and anthropogenic impacts. Benthic diatoms, in particular, can provide useful indications on the deleterious effects of non-native fish introduction, cattle grazing, and global warming, and thus support an adaptive and sustainable management of high-mountain lakes for the sake of nature conservation

Efficacy of Utilization of All-Plant-Based and Commercial Low-Fishmeal Feeds in Two Divergently Selected Strains of Rainbow Trout (Oncorhynchus mykiss): Focus on Growth Performance, Whole-Body Proximate Composition, and Intestinal Microbiome

The present study aimed to investigate the growth performance, whole-body proximate composition, and intestinal microbiome of rainbow trout strains when selected and non-selected for weight gain on all-plant protein diets. A 2x2 factorial design was applied, where a selected (United States) and a non-selected (ITA) rainbow trout strain were fed using either an all-plant protein (PP) or a commercial low-FM diet (C). Diets were fed to five replicates of 20 (PP) or 25 (C) fish for 105 days. At the end of the trial, growth parameters were assessed, and whole fish (15 pools of three fish/diet) and gut samples (six fish/diet) were collected for whole-body proximate composition and gut microbiome analyses, respectively. Independent of the administered diet, the United States strain showed higher survival, final body weight, weight gain, and specific growth rate when compared to the ITA fish (p < 0.001). Furthermore, decreased whole-body ether extract content was identified in the PP-fed United States rainbow trout when compared to the ITA strain fed the same diet (p < 0.001). Gut microbiome analysis revealed the Cetobacterium probiotic-like genus as clearly associated with the United States rainbow trout, along with the up-regulation of the pathway involved in starch and sucrose metabolism. In summary, the overall improvement in growth performance and, to a lesser extent, whole-body proximate composition observed in the selected rainbow trout strain was accompanied by specific, positive modulation of the intestinal microbiome

Food safety considerations in relation to Anisakis pegreffii in anchovies (Engraulis encrasicolus) and sardines (Sardina pilchardus) fished off the Ligurian Coast (Cinque Terre National Park, NW Mediterranean)

Aims: The purpose of this work was to verify whether E. coli is a good indicator of viral contamination in mussels and Adenovirus could represent a better alternative as indicator organism of viral presence to guarantee consumer health protection. Methods and Results: Eighty samples of mussels from La Spezia Gulf were analysed for E. coli, Salmonella, Adenovirus, Norovirus and hepatitis A virus with cultural and biomolecular tests. The results of bacterial parameters showed E. coli within the law’s limits and the absence of Salmonella. Twelve samples were positive for Adenovirus presence, one for Norovirus genogroup II and two for hepatitis A virus. None of these positive mussels was found to be contaminated with more than one virus at the same time. Conclusion: This study showed that there was not a direct correlation between the presence of human pathogenic viruses and bacterial indicators. Significance and Impact of the Study: Both E. coli and Adenovirus cannot be considered valid substitutes for the direct research of human pathogenic viruses in mussels. To improve consumer health protection, the European Commission will provide standardized methods for Norovirus and hepatitis A virus detection as soon as possible

Buccal swabs for long-term DNA storage in conservation genetics of fish: One-and-a-half-year analysis timeframe

Conservation genetic research is essential for the management and recovery of endangered taxa. However, the invasive collection of biological material for DNA analysis is controversial. From an ethical perspective, non-destructive sampling methods leave the aquatic specimen alive and less invasive procedures minimize stress on the animals. DNA can be obtained from fish using minimally invasive techniques such as buccal swabs. Here we evaluated the performance of buccal swabs for long-term storage of DNA obtained from brown trout (Salmo trutta). The buccal swabs were stored at room temperature and cut into pieces, one part of which was used for extraction of an aliquot and the others were stored as a “biobank” of biological material. The elapsed time from sampling to molecular analysis was one and half year. The amplification of three different DNA targets was tested to assess the effectiveness of the extraction: mitochondrial DNA (the D-LOOP region), nuclear DNA (the LDH gene) and microsatellite DNA at multiple loci. The results showed high quantification (mean value: 281.84±72.4 ng/μL), indicating that DNA could be effectively extracted from the buccal swabs. Our study results suggest that buccal swabs for long-term storage of DNA at room temperature are promising for use in field conservation studies

Assessment of Biological and Sanitary Condition of Alien Fish from a High-Mountain Lake (Cottian Alps)

This study aimed to assess the biological and sanitary conditions of alien fish in a high-mountain lake (Balma Lake) located in the Cottian Alps. A single fish sampling session (August 2018) using gillnets collected 90 specimens of brook trout (Salvelinus fontinalis). Sex and age were determined (59 females and 31 males, age class 0+ to 4+). Regression analysis showed no difference in total weight and total length between males and females (ANCOVA: F = 0.453; p = 0.954). The mean condition factor (Kmean) decreased with increasing age for males and females. Terrestrial insects were the main prey found in the fish stomachs. The parasitological exam was negative, and the bacteriological exam was positive for Carnobacterium maltaromaticum and C. divergens in 33% of specimens. The total mercury, cadmium, and lead concentration in muscle tissue was within the maximum limit established by the European Commission for human consumption. The brook trout population was found to be well structured; these findings may help local administrations in the implementation of eradication measures

The unusual isolation of carnobacteria in eyes of healthy salmonids in high‑mountain lakes

Carnobacteria are common bacteria in cold and temperate environments; they are also reported during fsh mortality events. In a previous study, carnobacteria were isolated from the eyes of healthy wild salmonids from a high-mountain lake. To better understand these fndings, salmonids were captured from three high-mountain lakes (Lower and Upper Balma Lake, Rouen Lake; northwest Italy) during August 2019 and subjected to bacteriological and histological examination. Although all were healthy, 8.7% (Lower Balma Lake), 24% (Upper Balma Lake), and 32.6% (Rouen Lake) were positive for carnobacteria colonization of the eyes. A Trojan-horse efect was hypothesized to explain carnobacteria isolation in the eye. This immune-escaping macrophage-mediated mechanism has been identifed in other Gram-positive bacteria. Biochemical, molecular, and phylogenetic analysis were carried out on isolated bacteria (Carnobacterium maltaromaticum and C. divergens). Based on previous references for carnobacteria isolated from fsh, C. maltaromaticum strains were tested for the pisA precursor gene of the bacteriocin piscicolin 126. Carnobacterium maltaromaticum strains were found to display genotypic heterogeneity and a low percentage of pisA positive amplifcation. Features of geomorphology, geographic isolation, and microbiota common to the three lakes are thought to be possibly related to our fndings. Moreover, terrestrial insects collected from the lake shoreline and the stomach contents were screened for the presence of carnobacteria. The salmonids in these high-mountain environments feed mainly on terrestrial insects, which are considered possible vectors for carnobacteria that might catabolize the exoskeleton chitin. All insects tested negative for carnobacteria, but as a small number of samples were analyzed, their role as possible vectors of infection cannot be excluded. Further studies are needed to corroborate our research hypothesis

U.V.A.C. MONITORING OF HEAVY METALS IN CONTROLLED MILK AND ITS PRODUCTS IN TURIN DURING 2007

The contamination of food by chemical is a worldwide public health concern and is a leading cause of trade problems internationally. Contamination may occur through environmental pollution of air, water and soil, such as heavy metals (As, Cd, Cr, Fe, Hg, Pb), PCB and dioxins, or through the intentional use of various pesticides and other agrochemicals. The AA controlled, during 2007, 26 samples of milk, 2 samples of dessert and 32 samples of cheese coming from UE to the area of the City of Turin. The collected demonstrate that the environmental situation is under control and the milk, dessert and cheese fully satisfy this health requisite