We reexamine the influential parental investment hypothesis proposed by Trivers for the causal relationship between anisogamy and widespread female‐biased parental care. We build self‐consistent versions of Maynard Smith's simple evolutionary game between males and females over parental care, and incorporate consequences of anisogamy for gamete production and its trade‐off with parental care, and for patterns of mate limitation. As male mating opportunities are limited by females, frequency‐dependent selection acts on male strategies. Assuming synchrony of matings in the population, our analytical models find either symmetric sex roles or male‐biased care as an evolutionarily stable strategy (ESS), in contrast to Trivers' hypothesis. We simulate evolution in asynchronously mating populations and find that diverse parental roles, including female care, can be ESS depending on the parameters. When caring males can also remate, or when females can increase the clutch size by deserting, there is stronger selection for male‐biased care. Hence, we argue that the mating‐caring trade‐off for males is neither a necessary consequence of anisogamy nor sufficient to select for female‐biased care. Instead, the factors excluded from our models—costly competitive traits, sexual selection, and partial parentage—may be necessary for the parental investment hypothesis to work.

Background. Local anesthesia is given to decrease pain perception during dental treatments, but it may itself be a reason for pain and aggravate the dental fear. Computer-controlled local anesthetic delivery system (CCLADS) is one of the alternatives for decreasing the patients’ pain during local anesthesia. This study compared the time required for the recovery from anesthesia, pain/discomfort during injection and pain/discomfort 24 hours after administering local anesthesia with CCLADS, a standard self-aspirating syringe and a conventional disposable 2-mL syringe. Methods. The study was conducted on 90 subjects (an age group of 20-40 years), who suffered from sensitivity during cavity preparation. They were randomly divided into three groups of 30 individuals each to receive intraligamentary anesthesia (2% lignocaine with 1:80,000 adrenaline) using either of the three techniques: CCLADS, a standard self-aspirating syringe, or a conventional disposable 2-mL syringe. The onset of anesthesia, time required for recovery from anesthesia (in minutes), pain/discomfort during injection and pain/discomfort 24 hours after administering local anesthesia were recorded. Results. The time required for the onset of anesthesia and recovery from anesthesia was shorter with CCLADS (4.83±2.31 and 34.2±1.895, respectively) as compared to the standard self-aspirating group (10.83±1.90 and 43.5±7.581, respectively) and the conventional group (11.00±2.03 and 43.5±6.453, respectively) (P<0.001). The patients in the CCLADS group experienced no pain during local anesthesia administration as compared to the patients in the self-aspirating and conventional groups. The CCLADS and self-aspirating groups showed lower pain response as compared to the conventional group for pain after 24 hours. Conclusion. CCLADS can be an effective and pain-free alternative to conventional local anesthetic procedures.

Classic computational models of collective motion suggest that simple local averaging rules can promote many observed group-level patterns. Recent studies, however, suggest that rules simpler than local averaging may be at play in real organisms; for example, fish stochastically align towards only one randomly chosen neighbour and yet the schools are highly polarized. Here, we ask—how do organisms maintain group cohesion? Using a spatially explicit model, inspired from empirical investigations, we show that group cohesion can be achieved in finite groups even when organisms randomly choose only one neighbour to interact with. Cohesion is maintained even in the absence of local averaging that requires interactions with many neighbours. Furthermore, we show that choosing a neighbour randomly is a better way to achieve cohesion than interacting with just its closest neighbour. To understand how cohesion emerges from these random pairwise interactions, we turn to a graph-theoretic analysis of the underlying dynamic interaction networks. We find that randomness in choosing a neighbour gives rise to well-connected networks that essentially cause the groups to stay cohesive. We compare our findings with the canonical averaging models (analogous to the Vicsek model). In summary, we argue that randomness in the choice of interacting neighbours plays a crucial role in achieving cohesion.

Gagging is an involuntary protective reflex. Some patients have an extremely low threshold for the gag reflex. A severe gag reflex can be a big obstacle in certain dental procedures especially during the making of a maxillary impression. Many dental patients avoid going to the dentist because of an abnormally severe gag reflex. Treating such group of patients can be stressful and a time-consuming experience, both for the dentist and for the patient. The main aim of this article is to understand the etiology and effective management of such patients for a stress-free and fruitful clinical practice.

The bone available for implant placement may be limited by the presence of the maxillary sinus togetherwith loss of alveolar bone height and it may be increased by augmentation. Minimally invasive sinusaugmentation is an effective solution for this problem. This review explains indirect sinus augmentationprocedures which are less invasive and highly successful if done using prescribed technique.