An inexpensive camera system for monitoring cavity nests

ABSTRACT A variety of pole‐mounted cameras have been developed for monitoring nest cavities. However, currently available camera systems may either be prohibitively expensive or difficult to assemble. I developed an inexpensive (<$500 US) and easily assembled camera system that allows researchers to monitor cavity nests from the ground. The system consists of a small camera, a cable connecting the camera to a ground‐level power source and laptop computer, and a flexible neck connecting the camera to a telescoping pole. During a study of Red‐headed Woodpeckers (Melanerpes erythrocephalus), I used this camera to inspect 16 nests and found that the images were clear and allowed accurate counts of eggs and nestlings. This camera system uses standard, off‐the‐shelf components, and can easily be altered. The design is not appropriate for humid or dense‐canopy environments because of the inclusion of a laptop and its wired design. However, this design makes the system inexpensive and allows researchers to save, edit, and view nest inspection recordings.     

Nodule froid et goitre de Basedow : étude préliminaire à partir de deux observations à Abidjan

We report two cases of cold nodules on Graves goiter in two young adults, female. These nodules showed no character of malignancy on cytology study after fine-needle aspiration. The authors discuss the importance of scintigraphy in the monitoring of a nodular goiter or Graves’ disease in order not to disregard a cold nodule and to perform surgery route to a histological diagnosis of certainty.     

Alternative stable states in communities with intraguild predation

Intraguild predation (IGP) is a widespread ecological phenomenon in which two consumers that share a resource also engage in a predator-prey interaction. Theory on IGP predicts the occurrence of alternative stable states, but empirical evidence of such states is scarce. This raises the question of whether alternative states are a rare phenomenon that is unlikely to be observed in nature. Here we analyze a model in which the resource exhibits logistic or chemostat dynamics and consumers have saturating (Type II) functional responses. We show that alternative states can arise for a wide range of biological scenarios and that environmental constraints can make their detection difficult. Our analysis identifies three possible combinations of alternative states: (i) IG prey or IG predator, (ii) coexistence or IG predator, and (iii) coexistence or IG prey. Bifurcation diagrams reveal that alternative states are possible over large regions of the parameter space. However, they can be limited to narrow ranges along the resource productivity axis, which may make it difficult to observe the occurrence of alternative states in communities with IGP. Microcosm experiments provide a promising avenue for detecting combinations of asymptotically stable states along a productivity gradient.     

Periplasmic protein EipA determines envelope stress resistance and virulence in Brucella abortus

Molecular components of the Brucella abortus cell envelope play a major role in its ability to infect, colonize and survive inside mammalian host cells. In this study, we have defined a role for a conserved gene of unknown function in B. abortus envelope stress resistance and infection. Expression of this gene, which we name eipA, is directly activated by the essential cell cycle regulator, CtrA. eipA encodes a soluble periplasmic protein that adopts an unusual eight‐stranded β‐barrel fold. Deletion of eipA attenuates replication and survival in macrophage and mouse infection models, and results in sensitivity to treatments that compromise the cell envelope integrity. Transposon disruption of genes required for LPS O‐polysaccharide biosynthesis is synthetically lethal with eipA deletion. This genetic connection between O‐polysaccharide and eipA is corroborated by our discovery that eipA is essential in Brucella ovis, a naturally rough species that harbors mutations in several genes required for O‐polysaccharide production. Conditional depletion of eipA expression in B. ovis results in a cell chaining phenotype, providing evidence that eipA directly or indirectly influences cell division in Brucella. We conclude that EipA is a molecular determinant of Brucella virulence that functions to maintain cell envelope integrity and influences cell division.