Genome sequence of the metazoan plant-parasitic nematode Meloidogyne incognita

Plant-parasitic nematodes are major agricultural pests worldwide and novel approaches to control them are sorely needed. We report the draft genome sequence of the root-knot nematode Meloidogyne incognita, a biotrophic parasite of many crops, including tomato, cotton and coffee. Most of the assembled sequence of this asexually reproducing nematode, totaling 86 Mb, exists in pairs of homologous but divergent segments. This suggests that ancient allelic regions in M. incognita are evolving toward effective haploidy, permitting new mechanisms of adaptation. The number and diversity of plant cell wall-degrading enzymes in M. incognita is unprecedented in any animal for which a genome sequence is available, and may derive from multiple horizontal gene transfers from bacterial sources. Our results provide insights into the adaptations required by metazoans to successfully parasitize immunocompetent plants, and open the way for discovering new antiparasitic strategies.

A Census-based longitudinal study of variations in survival amongst residents of nursing and residential homes in Northern Ireland

Background: despite the intensive services provided to residents of care homes, information on death rates is not routinely available for this population in the UK. Objective: to quantify mortality rates across the care home population of Northern Ireland, and assess variation by type of care home and resident characteristics. Design: a prospective, Census-based cohort study, with 5-year follow-up. Participants: all 9,072 residents of care homes for people aged 65 and over at the time of the 2001 census with a special emphasis on the 2,112 residents admitted during the year preceding census day. Measurements: age, sex, self-reported health, marital status, residence (not in care home, residential home, dual registered home, nursing home), elderly mentally infirm care provision. Results: the median survival among nursing home residents was 2.33 years (95% CI 2.25–2.59), for dual registered homes 2.75 (95% CI 2.42–3.17) and for residential homes 4.51 (95% CI 3.92–4.92) years. Age, sex and self-reported health showed weaker associations in the sicker populations in nursing homes compared to those in residential care or among the non-institutionalised. Conclusions: the high mortality in care homes indicates that places in care homes are reserved for the most severely ill and dependent. Death rates may not be an appropriate care quality measure for this population, but may serve as a useful adjunct for clinical staff and the planning of care home provision.

How many processes underline category-based induction? Effect of conclusion specificity and cognitive ability

Two studies investigated participants' sensitivity to the amount and diversity of the evidence when reasoning inductively about categories. Both showed that participants are more sensitive to characteristics of the evidence for arguments with general rather than specific conclusions. Both showed an association between cognitive ability and sensitivity to these evidence characteristics, particularly when the conclusion category was general. These results suggest that a simple associative process may not be sufficient to capture some key phenomena of category-based induction. They also support the claim that the need to generate a superordinate category is a complicating factor in category-based reasoning and that adults' tendency to generate such categories while reasoning has been overestimated.