Contact rate modulates foraging efficiency in leaf cutting ants.

Lane segregation is rarely observed in animals that move in bidirectional flows. Consequently, these animals generally experience a high rate of head-on collisions during their journeys. Although these collisions have a cost (each collision induces a delay resulting in a decrease of individual speed), they could also have a benefit by promoting information transfer between individuals. Here we explore the impact of head-on collisions in leaf-cutting ants moving on foraging trails by artificially decreasing the rate of head-on collisions between individuals. We show that head-on collisions do not influence the rate of recruitment in these ants but do influence foraging efficiency, i.e. the proportion of ants returning to the nest with a leaf fragment. Surprisingly, both unladen and laden ants returning to the nest participate in the modulation of foraging efficiency: foraging efficiency decreases when the rate of contacts with both nestbound laden or unladen ants decreases. These results suggest that outgoing ants are able to collect information from inbound ants even when these latter do not carry any leaf fragment and that this information can influence their foraging decisions when reaching the end of the trail.

Collective choice in ants: the role of protein and carbohydrates ratios.

In a foraging context, social insects make collective decisions from individuals responding to local information. When faced with foods varying in quality, ants are known to be able to select the best food source using pheromone trails. Until now, studies investigating collective decisions have focused on single nutrients, mostly carbohydrates. In the environment, the foods available are a complex mixture and are composed of various nutrients, available in different forms. In this paper, we explore the effect of protein to carbohydrate ratio on ants' ability to detect and choose between foods with different protein characteristics (free amino acids or whole proteins). In a two-choice set up, Argentine ants Linepithema humile were presented with two artificial foods containing either whole protein or amino acids in two different dietary conditions: high protein food or high carbohydrate food. At the collective level, when ants were faced with high carbohydrate foods, they did not show a preference between free amino acids or whole proteins, while a preference for free amino acids emerged when choosing between high protein foods. At the individual level, the probability of feeding was higher for high carbohydrates food and for foods containing free amino acids. Two mathematical models were developed to evaluate the importance of feeding probability in collective food selection. A first model in which a forager deposits pheromone only after feeding, and a second model in which a forager always deposits pheromone, but with greater intensity after feeding. Both models were able to predict free amino acid selection, however the second one was better able to reproduce the experimental results suggesting that modulating trail strength according to feeding probability is likely the mechanism explaining amino acid preference at a collective level in Argentine ants.

Patient information ahead of thyroid surgery. Guidelines of the French Society of Oto-Rhino-Laryngology and Head and Neck Surgery (SFORL).

OBJECTIVE: The authors present the guidelines of the French Society of Oto-Rhino-Laryngology and Head and Neck Surgery (SFORL) on patient information ahead of thyroid surgery. METHODS: A multidisciplinary medical team was tasked with a scientific literature review on this topic. The texts retrieved were analyzed by an independent committee. A joint meeting drew up the final guidelines. The strength of the recommendations (grade A, B or C) was based on levels of evidence. RESULTS: It is recommended that the results of preoperative exploration and the indications for surgery should be explained to the patient. Patients should be informed as to the type of surgery, surgical objectives, risks and consequences. It is mandatory to obtain the patient's written consent before surgery. CONCLUSION: Appropriate medical information is a critical step in patient management.

Cavernous sinus thrombosis secondary to non-invasive sphenoid aspergillosis.

The sphenoid localization of aspergillosis is a rare sinusal disease, often latent or asymptomatic. The neurological complications are the result of invasive forms occurring in most cases for the immunocompromised or diabetic patients. Nevertheless, non-invasive sphenoid aspergillosis may cause also several complications and affect the vital prognosis of nonimmunocompromised patients. This report is about two cases of cavernous sinus thrombosis secondary to a non-invasive sphenoid aspergillosis. The authors refer to the clinical and radiological findings and therapeutic approach of this rare complication.

[Clinical effectiveness and tolerance of loratadine versus cetirizine in the treatment of seasonal allergic rhinitis]. / Efficacité clinique et tolérance de la Loratadine versus Cétirizine dans le traitement de la rhinite allergique saissonnière.

A double blind multicentre study of seasonal rhinitis (108 patients) has compared Loratadine and Cetirizine. The results of clinical scores are significantly good for both products. Only tolerance is different and in favour of Loratadine, since sleepiness was found in 9.5% of patients treated with Cetirizine, and 3.6% with Loratadine.

[Pathogenic role of Actinomyces apart from actinomycosis. Apropos of 2 cases of acute suppurations with Actinomyces odontolyticus]. / Le rôle pathogène des Actinomyces en dehors de l'actinomycose. A propos de deux cas de suppurations aiguës contenant Actinomyces odontolyticus.

The authors report two cases of acute suppurative lesions due to Actinomyces odontolyticus. They point out the fairly high incidence of this pathogen in such conditions, either isolated or more often as part of a mixed flora. Conversely, Actinomyces odontolyticus is only exceptionally recovered in true actinomycosis.