Compensatory Breeding in Years Following Drought in a Desert-Dwelling Cooperative Breeder

Variation in weather patterns can influence reproductive effort and success not only within but also between breeding seasons. Where environmental conditions can be highly variable between years, the weather, and particularly extreme weather events such as heat waves and droughts, may exert a strong influence on reproductive effort (number of breeding attempts) and success (number of surviving young) from one breeding season to the next. We used a 15-year dataset for a cooperatively-breeding bird, the southern pied babbler Turdoides bicolor, to determine the impact of high temperatures and drought on reproductive effort and success. We tested the influence on reproductive effort and success of mean daily maximum air temperature and drought both within a breeding season, to determine the relative importance of current conditions, and during the previous breeding season, to determine the relative importance of compensatory effects in response to prior conditions. Reproductive effort and success were lower during breeding seasons characterised by drought, and higher in the breeding seasons that followed droughts, but were not predicted by mean daily maximum temperatures measured over the full length of the breeding season. We provide evidence of compensatory breeding following drought in a bird species endemic to a semi-arid ecosystem and suggest that compensatory mechanisms may be an important part of both long-term population persistence and post-drought population recovery.DST-NRF Centre of Excellence at the FitzPatrick Institute for African Ornithology Oppenheimer Memorial Trust (Grant No. 20747/01 to ARB) British Ornithologists’ Union Australian Research Council (Grant No. FT110100188 to ARR) National Research Foundation of South Africa (Grant No. 110506 to SJC

Exploring the self-ownership effect: Separating stimulus and response biases.

Although ownership is acknowledged to exert a potent influence on various aspects of information processing, the origin of these effects remains largely unknown. Based on the demonstration that self-relevance facilitates perceptual judgments (i.e., the self-prioritization effect), here we explored the possibility that ownership enhances object categorization. The results of 2 experiments supported this prediction. Compared with items owned by a stranger (Expt. 1) or best friend (Expt. 2), those owned by the self were classified most rapidly (i.e., self-ownership effect) in an object-categorization task. To establish the basis of this effect, the processes underlying task performance were interrogated using a hierarchical drift diffusion model (HDDM) approach. Results of these analyses revealed that self-ownership was underpinned by a response bias (i.e., starting point of evidence accumulation). These findings explicate the origin of the ownership effect during object processing. (PsycINFO Database Recor

Self-relevance prioritizes access to visual awareness.

As we are cognizant of only a fraction of the available visual inputs at any given time, how is information selected for access to consciousness? In particular, does the personal significance of stimuli influence perceptual selection? Given that self-relevant information is prioritized during various stages of processing, here we hypothesized that self-association may privilege access to awareness under continuous flash suppression (CFS). The results supported this prediction. Compared with geometric shapes referenced to either a friend or stranger, those previously associated with self were prioritized in visual awareness. To establish the basis of this effect, the processes underlying task performance were investigated using a hierarchical drift diffusion model approach. These analyses showed that self-prioritization mapped onto both the decisional (i.e., starting value, z) and nondecisional (i.e., t₀) parameters of the diffusion model. The implications of these findings are considered. (PsycINFO Database Recor

Stop stereotyping.

Restraining the expression of stereotypes is a necessary requirement for harmonious living, yet surprisingly little is known about the efficacy of this process. Accordingly, in two experiments, here we used a stop-signal task to establish how effectively stereotype-related responses can be inhibited. In Experiment 1, following the presentation of gender-typed occupational contexts, participants reported the sex of target faces (i.e., Go trials) unless an occasional auditory tone indicated they should withhold their response (i.e., Stop trials). In Experiment 2, following the presentation of male and female faces, participants made either stereotypic or counter-stereotypic judgments, unless a stop signal was presented. Regardless of whether stereotyping was probed indirectly (Experiment 1) or directly (Experiment 2), a consistent pattern of results was observed; inhibition was faster for stereotypic compared with counter-stereotypic responses. These findings demonstrate that stopping stereotyping may be less challenging than has widely been assumed

An extracellular steric seeding mechanism for Eph-ephrin signaling platform assembly

Erythropoetin-producing hepatoma (Eph) receptors are cell-surface protein tyrosine kinases mediating cell-cell communication. Upon activation, they form signaling clusters. We report crystal structures of the full ectodomain of human EphA2 (eEphA2) both alone and in complex with the receptor-binding domain of the ligand ephrinA5 (ephrinA5 RBD). Unliganded eEphA2 forms linear arrays of staggered parallel receptors involving two patches of residues conserved across A-class Ephs. eEphA2-ephrinA5 RBD forms a more elaborate assembly, whose interfaces include the same conserved regions on eEphA2, but rearranged to accommodate ephrinA5 RBD. Cell-surface expression of mutant EphA2s showed that these interfaces are critical for localization at cell-cell contacts and activation-dependent degradation. Our results suggest a 'nucleation' mechanism whereby a limited number of ligand-receptor interactions 'seed' an arrangement of receptors which can propagate into extended signaling arrays

Giant pedunculated hepatocellular carcinoma with hemangioma mimicking intestinal obstruction

<p>Abstract</p> <p>Background</p> <p>Pedunculated hepatocellular carcinoma (P-HCC) has rarely been reported and is characteristically large and encapsulated. Only sporadic cases have been published, in which P-HCC was combined with other liver tumors (mostly benign), making the diagnosis difficult.</p> <p>Case presentation</p> <p>We report a patient who was admitted to our hospital with clinical features of intestinal obstruction and a palpable mass in the right iliac fossa. Ultrasound, computed tomography and magnetic resonance imaging demonstrated an encapsulated mass of unclear origin and characteristics of liver hemangioma. Laboratory tests revealed elevated α-fetoprotein (> 800 ng/ml) and cancer antigen 125 (> 51.2 U/ml). With a possible diagnosis of giant liver hemangioma, we proceeded to surgery. During surgery, a giant pedunculated tumor was discovered on the inferior surface of the right lobe of the liver, hanging free in the right abdominal cavity towards the right iliac fossa. The macroscopic appearance of the tumor was compatible with liver hemangioma. Tumor resection was performed at a safe distance, including the pedicle. The rest of the liver appeared normal. Histopathological examination revealed grade II and III HCC (according to Edmondson-Steiner's classification) with nodular configuration, central necrosis, and infiltration of the capsule. Underneath the tumor capsule, residual tissue of a cavernous hemangioma was recognized. The resection margins were free of neoplastic tissue.</p> <p>Conclusion</p> <p>This rare presentation of a giant P-HCC combined with a hemangioma with features of intestinal obstruction confirmed the diagnostic difficulties of similar cases, and required prompt surgical treatment. Therefore, patients benefit from surgical resection because both the capsule and the pedicle prevent vascular invasion, therefore improving prognosis.</p

The pharmacological regulation of cellular mitophagy

Small molecules are pharmacological tools of considerable value for dissecting complex biological processes and identifying potential therapeutic interventions. Recently, the cellular quality-control process of mitophagy has attracted considerable research interest; however, the limited availability of suitable chemical probes has restricted our understanding of the molecular mechanisms involved. Current approaches to initiate mitophagy include acute dissipation of the mitochondrial membrane potential (ΔΨm) by mitochondrial uncouplers (for example, FCCP/CCCP) and the use of antimycin A and oligomycin to impair respiration. Both approaches impair mitochondrial homeostasis and therefore limit the scope for dissection of subtle, bioenergy-related regulatory phenomena. Recently, novel mitophagy activators acting independently of the respiration collapse have been reported, offering new opportunities to understand the process and potential for therapeutic exploitation. We have summarized the current status of mitophagy modulators and analyzed the available chemical tools, commenting on their advantages, limitations and current applications