Livistona palms in Australia: Ancient relics or opportunistic immigrants?

Eighteen of the 34 species of the fan palm genus Livistona (Arecaceae) are restricted to Australia and southern New Guinea, east of Wallace’s Line, an ancient biogeographic boundary between the former supercontinents Laurasia and Gondwana. The remaining species extend from SE Asia to Africa, west of Wallace’s Line. Competing hypotheses contend that Livistona is (a) ancient, its current distribution a relict of the supercontinents, or (b) a Miocene immigrant from the north into Australia as it drifted towards Asia. We have tested these hypotheses using Bayesian and penalized likelihood molecular dating based on 4 Kb of nuclear and chloroplast DNA sequences with multiple fossil calibration points. Ancestral areas and biomes were reconstructed using parsimony and maximum likelihood. We found strong support for the second hypothesis, that a single Livistona ancestor colonized Australia from the north about 10–17 Ma. Spread and diversification of the genus within Australia was likely favoured by a transition from the aseasonal wet to monsoonal biome, to which it could have been preadapted by fire-tolerance.     

Nuclear receptors. I. PPAR gamma in the gastrointestinal tract: gain or pain?

The peroxisome proliferator-activated receptor gamma (PPAR gamma) has recently been implicated in the pathogenesis of inflammatory bowel disease (IBD) and colon cancer. The observation that PPAR gamma agonists, through immune modulation, protect against inflammatory processes in the intestine justified their expedient evaluation in the clinical management of IBD. PPAR gamma agonists are reported to have both tumor-promoting and -inhibiting effects in models of colon cancer. These differences can, in part, be explained by PPAR gamma-independent effects of PPAR gamma agonists and by differences in the models used. Because it is still unclear how PPAR gamma impacts on colon cancer, careful monitoring of patients receiving PPAR gamma agonists and additional basic research is indicated before recommendations on the use of PPAR gamma ligands in colon cancer can be made.     

Somatic mutations in mitochondria: the chicken or the egg?

Somatic mutations of mitochondrial DNA have been detected in various pathologies such as cancer, neurodegenerative diseases, cardiac disorders and aging in general. Now it has been found that patients with rheumatoid arthritis also have a higher incidence of mitochondrial mutations in synoviocytes and synovial tissue compared with patients with osteoarthritis. Furthermore, it has been shown that these mutations possibly result in changed peptides that are presented by major histocompatibility complex II and thus might be recognized as non-self by the immune system. Further studies will show whether these mutations are actually able to trigger autoimmune inflammation in rheumatoid arthritis or whether they must be considered epiphenomena of cellular damage in chronic inflammation.     

Organellar genes: why do they end up in the nucleus?

Many mitochondrial and plastid proteins are derived from their bacterial endosymbiotic ancestors, but their genes now reside on nuclear chromosomes instead of remaining within the organelle. To become an active nuclear gene and return to the organelle as a functional protein, an organellar gene must first be assimilated into the nuclear genome. The gene must then be transcribed and acquire a transit sequence for targeting the protein back to the organelle. On reaching the organelle, the protein must be properly folded and modified, and in many cases assembled in an orderly manner into a larger protein complex. Finally, the nuclear copy must be properly regulated to achieve a fitness level comparable with the organellar gene. Given the complexity in establishing a nuclear copy, why do organellar genes end up in the nucleus? Recent data suggest that these genes are worse off than their nuclear and free-living counterparts because of a reduction in the efficiency of natural selection, but do these population-genetic processes drive the movement of genes to the nucleus? We are now at a stage where we can begin to discriminate between competing hypotheses using a combination of experimental, natural population, bioinformatic and theoretical approaches.     

Japan’s Hidden Youths: Mainstreaming the Emotionally Distressed in Japan

One of the most talked-about social issues in Japan in recent years has been the problem of the nation's purportedly one million "hidden" youths, known as hikikomori (literally, "the withdrawn"). Most observers agree that the category of hikikomori encompasses a wide range of problems and provocations. The fact that these various dilemmas lead to the shared outcome of shutting oneself away at home is the point of departure here. The article explores the spheres of mental health care, education and family, focusing on the reluctance to highlight underlying psychological dimensions of hikikomori and the desire on the part of schools and families to "mainstream" Japanese children, accommodating as many as possible within standardized public education. Hikikomori can perhaps be seen as a manifestation of Japanese democracy, in which the good society is imagined as cohesive, protective and secure, rather than one in which the individual can freely exercise the right to be different. Schools, families and the sphere of mental health care have focused on producing social inclusion but have discouraged citizens from being labeled as "different" -- even when such a distinction might help them. The dearth of facilities and discourse for caring for the mentally ill or learning disabled is, in many respects, the darker side of Japan's successes. Those who cannot adjust are cared for through the institutions of families, companies and various other spheres that offer spaces to rest and to temporarily "drop out"; however, the expectation is that rest will eventually lead to a re-entry into mainstream society. Often the psychological problem or disability that led to the problem goes unnamed and untreated (hikikomori, psychiatry, special education, youth, family, Japan).     

Decision Rules and Group Rationality: Cognitive Gain or Standstill?

Recent research in group cognition points towards the existence of collective cognitive competencies that transcend individual group members’ cognitive competencies. Since rationality is a key cognitive competence for group decision making, and group cognition emerges from the coordination of individual cognition during social interactions, this study tests the extent to which collaborative and consultative decision rules impact the emergence of group rationality. Using a set of decision tasks adapted from the heuristics and biases literature, we evaluate rationality as the extent to which individual choices are aligned with a normative ideal. We further operationalize group rationality as cognitive synergy (the extent to which collective rationality exceeds average or best individual rationality in the group), and we test the effect of collaborative and consultative decision rules in a sample of 176 groups. Our results show that the collaborative decision rule has superior synergic effects as compared to the consultative decision rule. The ninety one groups working in a collaborative fashion made more rational choices (above and beyond the average rationality of their members) than the eighty five groups working in a consultative fashion. Moreover, the groups using a collaborative decision rule were closer to the rationality of their best member than groups using consultative decision rules. Nevertheless, on average groups did not outperformed their best member. Therefore, our results reveal how decision rules prescribing interpersonal interactions impact on the emergence of collective cognitive competencies. They also open potential venues for further research on the emergence of collective rationality in human decision-making groups.     

Knowledge,Attitudes, and Decision Making in Hospital Glycemic Management: are Faculty up to Speed?

Objective: Knowledge and confidence deficits in the management of hospital glucose abnormalities are prevalent among resident physicians. However, it is unclear whether such gaps prevail among faculty within different professional fields. In this study, we examined faculty knowledge and explored perceptions of challenges related to the management of inpatient hyperglycemia and diabetes.Methods: We conducted a survey that examined management decisions about inpatient hyperglycemia and diabetes among Medicine, Medicine/Pediatrics, Family and Community Medicine, Surgery, and Neurology faculty clinicians. All participating faculty had teaching and patient care responsibilities.Results: Responses from 69 faculty participants revealed gaps in several areas, including biomedical and contextual knowledge, familiarity with resources, clinical decision making, and self-efficacy. We identified important factors perceived as barriers to optimal glycemic management in the inpatient settings.Conclusion: The results of this study enhance our insight about the limitations existing among faculty related to the management of hyperglycemia and diabetes in hospitalized patients. We suggest that these barriers may impede optimization of patient care. Faculty play a crucial role in the clinical decision-making process and quality of care delivered by trainees. Therefore, attending physicians are likely to impact trainees' clinical performance and competency in the management of inpatient diabetes during training and beyond. Education in this subject should be a priority among trainees and faculty alike.Abbreviation: ICU = intensive care unit     

Signal-induced repression: the exception or the rule in developmental signaling?

Cell-cell communication plays a key role in organ formation and patterning in multicellular animals and is carried out by a few evolutionarily conserved signaling pathways. The modes of action of these pathways share a number of general properties, or habits, that allow them to strongly activate target genes in a ligand-dependent manner in the proper cellular contexts. Recent studies have revealed that some developmental signaling pathways can also strongly repress genes in a ligand-dependent manner. These new findings raise the interesting possibility that this repressive mode of action is shared by many or most developmental signaling pathways.     

Signaling in the plant cytosol: cysteine or sulfide?

Cysteine (Cys) is the first organic compound containing reduced sulfur that is synthesized in the last stage of plant photosynthetic assimilation of sulfate. It is a very important metabolite not only because it is crucial for the structure, function and regulation of proteins but also because it is the precursor molecule of an enormous number of sulfur-containing metabolites essential for plant health and development. The biosynthesis of Cys is accomplished by the sequential reaction of serine acetyltransferase (SAT) and O-acetylserine(thiol)synthase (OASTL). In Arabidopsis thaliana, the analysis of specific mutants of members of the SAT and OASTL families has demonstrated that the cytosol is the compartment where the bulk of Cys synthesis takes place and that the cytosolic OASTL enzyme OAS-A1 is the responsible enzyme. Another member of the OASTL family is DES1, a novel l-cysteine desulfhydrase that catalyzes the desulfuration of Cys to produce sulfide, thus acting in a manner opposite to that of OAS-A1. Detailed studies of the oas-a1 and des1 null mutants have revealed the involvement of the DES1 and OAS-A1 proteins in coordinate regulation of Cys homeostasis and the generation of sulfide in the cytosol for signaling purposes. Thus, the levels of Cys in the cytosol strongly affect plant responses to both abiotic and biotic stress conditions, while sulfide specifically generated from the degradation of Cys negatively regulates autophagy induced in different situations. In conclusion, modulation of the levels of Cys and sulfide is likely critical for plant performance.     

Scientific R&D: time to revise the rules?

For several decades scientific R&D has been failing communities around the world, especially in developing countries, by not producing an adequate level of benefits (for example, improved health and living standards) and essential public goods (for example, the provision of safe water, sanitation and energy). It is time for a complete overhaul of the R&D process, with a comprehensive review of the mechanisms by which R&D is financed, how and where the work and results are published and disseminated, how the results and knowledge are exploited, and how ownership is decided. This is particularly important for public goods, for which there is often no market or prospect of commercial return or profit.     

AgRP in energy balance: Will the real AgRP please stand up?

The neuropeptide AgRP promotes food intake and weight gain by antagonizing signaling at melanocortin 3 and 4 receptors in the brain, but the limited phenotype of mice lacking AgRP raised questions about its importance. Four recent studies addressed this by creating mice in which AgRP neurons, which also express NPY and GABA, are ablated postnatally, and although details vary, they suggest that AgRP neurons are more essential to feeding and weight gain than is AgRP itself. A recent paper in Cell Metabolism (Wortley et al., 2005) indicates that AgRP itself is important for feeding and weight gain, but only as mice age, and the mechanism may involve dysfunction of the thyroid axis.     

Which Is Better: Holdout or Full-Sample Classifier Design?

Is it better to design a classifier and estimate its error on the full sample or to design a classifier on a training subset and estimate its error on the holdout test subset? Full-sample design provides the better classifier; nevertheless, one might choose holdout with the hope of better error estimation. A conservative criterion to decide the best course is to aim at a classifier whose error is less than a given bound. Then the choice between full-sample and holdout designs depends on which possesses the smaller expected bound. Using this criterion, we examine the choice between holdout and several full-sample error estimators using covariance models and a patient-data model. Full-sample design consistently outperforms holdout design. The relation between the two designs is revealed via a decomposition of the expected bound into the sum of the expected true error and the expected conditional standard deviation of the true error.