Animal behaviour: elephants are capable of vocal learning

There are a few mammalian species that can modify their vocalizations in response to auditory experience--for example, some marine mammals use vocal imitation for reproductive advertisement, as birds sometimes do. Here we describe two examples of vocal imitation by African savannah elephants, Loxodonta africana, a terrestrial mammal that lives in a complex fission-fusion society. Our findings favour a role for vocal imitation that has already been proposed for primates, birds, bats and marine mammals: it is a useful form of acoustic communication that helps to maintain individual-specific bonds within changing social groupings.     

A monitoring system for the social development program in Colombia

This paper describes and analyzes “the Social Solidarity Network” (SSN), which is an agency of the Office of the President of the national government of Colombia. Its purpose is to promote self-development programs in the poorest communities in the country, as well as to improve their local public decision-making and other organizational mechanisms. The workings of the “monitoring system” used by the SSN, whose design has been inspired by Beer's ideas of monitoring and control, are introduced and discussed (Beer, 1979/1981a,b; Espejo and Harnden, 1989). The paper also offers a brief analysis of the structural mechanisms currently in use for communicating among local government agencies and the other departmental, regional, and national levels of government. This analysis indicates that the national authorities design and supervise the local planning and control mechanisms too closely and often ignore the existence and views of the intermediate recursions of government and the priorities of the local communities. The paper concludes with an assessment of the multi-university-based monitoring system used to follow up the activities and results of the SSN.     

Platelets as crucial partners for tumor metastasis: from mechanistic aspects to pharmacological targeting

Platelets are anucleated cells that circulate in the blood as sentinels of tissue integrity. In fact, they are rich in a plethora of proteins and other factors stored in different granules which they selectively release upon stimulation. Moreover, platelets synthesize a vast number of lipids and release various types of vesicles, including exosomes which are rich in genetic material. Platelets possess a central function to interact with other cell types, including inflammatory cells and cancer cells. Recent findings have enlightened the capacity of platelets to induce changes in the phenotype of cancer cells which acquire invasiveness thus enhancing their metastatic potential. Thus, it has been hypothesized that targeting the platelet may represent a novel strategy to prevent the development and progression of cancer. This is supported by the efficacy of the antiplatelet agent low-dose aspirin. Studies are ongoing to verify whether other antiplatelet agents share the anticancer effectiveness of aspirin.     

Genetic variation near IRS1 associates with reduced adiposity and an impaired metabolic profile

Genome-wide association studies have identified 32 loci influencing body mass index, but this measure does not distinguish lean from fat mass. To identify adiposity loci, we meta-analyzed associations between ～2.5 million SNPs and body fat percentage from 36,626 individuals and followed up the 14 most significant (P < 10(-6)) independent loci in 39,576 individuals. We confirmed a previously established adiposity locus in FTO (P = 3 × 10(-26)) and identified two new loci associated with body fat percentage, one near IRS1 (P = 4 × 10(-11)) and one near SPRY2 (P = 3 × 10(-8)). Both loci contain genes with potential links to adipocyte physiology. Notably, the body-fat-decreasing allele near IRS1 is associated with decreased IRS1 expression and with an impaired metabolic profile, including an increased visceral to subcutaneous fat ratio, insulin resistance, dyslipidemia, risk of diabetes and coronary artery disease and decreased adiponectin levels. Our findings provide new insights into adiposity and insulin resistance.     

SERRATE coordinates shoot meristem function and leaf axial patterning in Arabidopsis

Leaves of flowering plants are determinate organs produced by pluripotent structures termed shoot apical meristems. Once specified, leaves differentiate an adaxial (upper) side specialized for light capture, and an abaxial (lower) side specialized for gas exchange. A functional relationship between meristem activity and the differentiation of adaxial leaf fate has been recognized for over fifty years, but the molecular basis of this interaction is unclear. In Arabidopsis thaliana, activity of the class I KNOX (KNOTTED1-like homeobox) genes SHOOTMERISTEMLESS (STM) and BREVIPEDICELLUS (BP) is required for meristem function but excluded from leaves, whereas members of the HD-Zip III (class III homeodomain leucine zipper) protein family function to promote both meristem activity and adaxial leaf fate. Here we show that the zinc-finger protein SERRATE acts in a microRNA (miRNA) gene-silencing pathway to regulate expression of the HD-Zip III gene PHABULOSA (PHB) while also limiting the competence of shoot tissue to respond to KNOX expression. Thus, SERRATE acts to coordinately regulate meristem activity and leaf axial patterning.     

Implications of changes in the UK social and occupational classifications in 2001 for vital statistics

In 2001, three simultaneous changes were introduced which influence the reporting of vital statistics by socio-economic status. Registrar General's Social Class was replaced by the new National Statistics Socio-Economic Status (NS SEC); the Standard Occupational Classification (SOC) was updated from SOC90 to SOC2000; and the coding of employment status on vital statistics changed to stay in line with census coding and SOC2000. This article reports on these changes and describes a method for coding data prior to 2001 to NS SEC (named NS SEC90) in order to facilitate the analysis of health inequalities over time. NS SEC90 allocates 90 per cent of deaths to the same analytical category as NS SEC. This figure varies according to sub group.     

Astronomical pacing of methane release in the Early Jurassic period

A pronounced negative carbon-isotope (delta13C) excursion of approximately 5-7 per thousand (refs 1-7) indicates the occurrence of a significant perturbation to the global carbon cycle during the Early Jurassic period (early Toarcian age, approximately 183 million years ago). The rapid release of 12C-enriched biogenic methane as a result of continental-shelf methane hydrate dissociation has been put forward as a possible explanation for this observation. Here we report high-resolution organic carbon-isotope data from well-preserved mudrocks in Yorkshire, UK, which demonstrate that the carbon-isotope excursion occurred in three abrupt stages, each showing a shift of -2 per thousand to -3 per thousand. Spectral analysis of these carbon-isotope measurements and of high-resolution carbonate abundance data reveals a regular cyclicity. We interpret these results as providing strong evidence that methane release proceeded in three rapid pulses and that these pulses were controlled by astronomically forced changes in climate, superimposed upon longer-term global warming. We also find that the first two pulses of methane release each coincided with the extinction of a large proportion of marine species.