Evaluation of New Components in Modified Scholten’s Medium for the Detection of Somatic Coliphages

Food and Environmental Virology - Enteric bacteriophages (somatic coliphages, F-specific coliphages or both together) are now recognized as useful viral indicators in water, shellfish, and...     

Cylinder cyclone (LARCODEMS) density media separation of plastic wastes

Cylindrical cyclone media separators using a suspended calcite separation media simulating industrial scale operations are demonstrated to effectively separate a wide variety of forms and a greater range of particle sizes of plastics by density than presently recycled. Purities of plastic products and recoveries obtained from mixed plastic wastes are comparable to those reported for established separations. Products of ≈100% purity with recoveries of >99% were obtained for high density fractions and >98% purities and recoveries for the low density fractions. Cyclonic centrifugal forces and/or the fine particle size of the separation media appear to minimize hydroscopic and particle shape effects.A mathematical model is proposed for defining plastic waste feed rates and treatable particle size ranges for the LARCODEMS media separator.Waste plastic separations yielded Ecart probable (Ep) values ?0.024 for a water only separation media. The Ep for 1.1 g cm^?3 separation medias was <0.032 with minimal to no variation in values for 1–8 mm particle sizes. Variation in the quality of separations is shown to be minimal with <72 μm, <45 μm and <2 μm media particle sizes. Media density offset created varied according to particle size.     

Effectiveness of protected areas in the Colombian Andes: deforestation, fire and land-use changes

Protected areas (PAs) are one of the most common conservation strategies to halt biodiversity loss. However, little is known about their current effectiveness and how they could behave under projected scenarios of change, especially in the mountain ecosystems of the Andean region. In this study, we assess the role of protected areas against deforestation and fire incidence in the Colombian Andes and how variables associated with biophysical and context drivers such as the size, year of creation and geographic location of the PAs affect their effectiveness. For the long-term, we have addressed the question of how effective these areas will be under three different scenarios of change for the period between 2020 and 2050, including a reference scenario and two scenarios of increasing pastureland and croplands. The results obtained indicated that both deforestation and fire levels were significantly lower inside protected areas than outside their borders. Concerning variables affecting deforestation and fire, only the type of ecosystem affected these processes in this study. The magnitude of forest loss was different between the analysed scenarios and depended on the location of the PAs. The PAs located in the Western Mountain Range presented the largest values of deforestation but the lowest number of fire incidences. This finding could be related to the presence of processes other than fire, such as illegal logging or selective extraction. The largest losses are expected in the PAs associated with the Eastern and Central mountain ranges, whereas the Western Mountain range will have the lowest loss. We conclude that although the Andes Mountains are a highly transformed and dynamic region, the current PAs have been effective barriers for deforestation and fire. However, the creation of new areas and the maintenance of the current PAs should take into account the interaction with the surrounding population, especially in those areas that are more sensitive to change.     

Dominance and the dynamics of phenotype-limited distribution in common cranes

We studied the behavior of 13 radiotagged cranes dispersing from a communal roost over days when they changed their main daily foraging area between consecutive days during two winter seasons. Individuals went to a new foraging zone when on the previous day their morning food intake had fallen below their mean morning food intake measured over the whole winter. Food intake on the day before a change in foraging area was positively correlated with dominance rank. Dominant cranes changed to new zones with higher numbers of birds and food density, while subordinate cranes went to new zones with lower numbers of birds. As a result, all birds increased their food intake over that of the previous day. Dominant cranes remained more faithful to their most preferred foraging zone, where they spent 69% of the mornings, while subordinate birds were more mobile, switching among zones frequently. Dominant birds left the roost later than subordinate birds on the days they changed to a new zone, which could be used to track the main departing flows. The results suggest that the dynamics that led to a truncated phenotype-limited distribution were determined by social dominance and food abundance, with dominant cranes shifting to a new zone to maintain their high intake levels and subordinates changing more frequently whenever their daily intake did not reach the minimum metabolic requirements. Received: 16 December 1996 / Accepted after revision: 22 February 1997     

The importance of crossroads in faecal marking behaviour of the wolves (<Emphasis Type="Italic">Canis lupus</Emphasis>)

For wolves (Canis lupus) scats play an important function in territorial marking behaviour. Depositing scats at strategic sites such as crossroads and on conspicuous substrates probably increases their effectiveness as visual and olfactory marks. It is therefore likely that scats will be deposited, and will accumulate, at particular crossroads where the probability of being detected by other wolves is greatest. To check this hypothesis, a wolf population in NW Spain was studied for two consecutive years, from May 1998 to March 2000, and the spatial distribution of 311 scats detected along roads (both at and away from crossroads) was analysed. This study was conducted over an area of 12,000 ha in Montes do Invernadeiro Natural Park. The results confirm that wolves preferably deposit their scats at crossroads (60.1%) and on conspicuous substrates (72.1%). Significantly more scats were found at intersections with numerous, easily passable roads connecting distant territories. Thus, wolves preferably deposit their faeces at crossroads with high accessibility and driveability. The larger the surface area of the crossroads, the more scats were found. Crossroads are therefore highly strategic points that facilitate the detection of scats.     

Non-invasive measurement of the physiological stress response of wild rabbits to the odour of a predator

Summary. Stress has been widely studied in different mammals, but the physiological stress reaction that the odour of a predator could induce in preys has not received much attention. Besides, not all the animals would respond to the same extent to a known stressor. We developed an experimental procedure with eleven na?ve European rabbits (Oryctolagus cuniculus) in order to determine the individual physiological response to the olfactory detection of a potential predator. The rabbits were housed singly in small enclosures with a concrete burrow system and food and water were available ad libitum. The animals followed a control trial, without odour, and an experimental trial where we confronted the rabbits with fox (Vulpes vulpes) odour. Furthermore, another sample of eleven rabbits followed a control procedure subjected to the same housing and handling procedures but without facing the predator odour. In order to assess the physiological response we analysed the concentration of glucocorticoid metabolites in the faeces of the rabbits. Therefore, everyday faecal samples were collected and analysed with an enzyme immunoassay in order to measure the corticosterone metabolites (CM), particularly, those metabolites with a 5α-3β, 11β-diol structure. After validating the assay for wild rabbits, we found that the simulated presence of a predator (fox odour) in the enclosure resulted in an increase in faecal CM concentrations. However, the stressor did not affect all the animals in the same way. We found a general increase in the individual differences. In particular, males experienced a higher increase than females, though the overall response was similar for both sexes. To our knowledge this is one of the first attempts to analyse the assessment of the risk of predation by means of non-invasive methods.     

Performance of a submerged membrane bioreactor system for biological nutrient removal.

A pilot submerged membrane bioreactor coupled with biological nutrient removal was used to treat the primary effluent at a municipal wastewater treatment plant. Long-term experiments were conducted by varying hydraulic retention time from 6 to 8 hours and solids retention time from 20 to 50 days, respectively. The performance was assessed by monitoring key wastewater parameters, including chemical oxygen demand (COD), nitrogen, and phosphorus concentration in individual anoxic, anaerobic, aerobic, and membrane separation zones. Results showed that the tested system can consistently achieve COD, nitrogen, and phosphorus removal efficiencies at 80 to 98%, 70 to 93%, and 89 to 98%, respectively. Effluent COD remained low as a result of efficient solid retention, even though there was great variation in influent quality. However, total nitrogen increased proportionally with influent concentration. At a 50-day solids retention time, higher COD and nitrogen oxides specific utilization rates in the anoxic zone resulted in a high production of nitrogen oxides in the subsequent aerobic zone.     

Wet peroxide degradation of atrazine

The high temperature (150-200 degrees C), high pressure (3.0-6.0 MPa) degradation of atrazine in aqueous solution has been studied. Under these extreme conditions atrazine steadily hydrolyses in the absence of oxidising agents. Additionally, oxygen partial pressure has been shown not to affect atrazine degradation rates. In no case mineralisation of the parent compound was observed. The addition of the free radical generator hydrogen peroxide to the reaction media significantly enhanced the depletion rate of atrazine. Moreover, partial mineralisation of the organics was observed when hydrogen peroxide was used. Again, oxygen presence did not influence the efficiency of the promoted reaction. Consecutive injections of hydrogen peroxide throughout the reaction period brought the total carbon content conversion to a maximum of 65-70% after 40 min of treatment (suggesting the total conversion of atrazine to cyanuric acid). Toxicity of the effluent measured in a luminometer decreased from 93% up to 23% of inhibition percentage. The process has been simulated by means of a semi-empirical model.