Paranoia,self-deception and overconfidence

Self-deception, paranoia, and overconfidence involve misbeliefs about the self, others, and world. They are often considered mistaken. Here we explore whether they might be adaptive, and further, whether they might be explicable in Bayesian terms. We administered a difficult perceptual judgment task with and without social influence (suggestions from a cooperating or competing partner). Crucially, the social influence was uninformative. We found that participants heeded the suggestions most under the most uncertain conditions and that they did so with high confidence, particularly if they were more paranoid. Model fitting to participant behavior revealed that their prior beliefs changed depending on whether the partner was a collaborator or competitor, however, those beliefs did not differ as a function of paranoia. Instead, paranoia, self-deception, and overconfidence were associated with participants’ perceived instability of their own performance. These data are consistent with the idea that self-deception, paranoia, and overconfidence flourish under uncertainty, and have their roots in low self-esteem, rather than excessive social concern. The model suggests that spurious beliefs can have value–self-deception is irrational yet can facilitate optimal behavior. This occurs even at the expense of monetary rewards, perhaps explaining why self-deception and paranoia contribute to costly decisions which can spark financial crashes and devastating wars.     

Characterization of plasma glycosaminoglycans in hemodialysis patients]

Glycosaminoglycans are heteropolysaccharides composed of disaccharide repeating subunits, each one containing a uronic acid component (glucuronic or iduronic acid) and a hexosamine (N-acetyl-glucosamine or N-acetyl-galactosamine, which may be differently sulphated). The presence of GAGs in human plasma has been demonstrated in several studies; they are bound to plasma proteins through non-covalent linkages. However, very little is known about either their origin or their physiological role. Due to their anionic charge, they may influence some metabolic processes, such as blood coagulation, and they could also have a role in urolithiasis and atherogenesis. Moreover, they may be important in modulating the metabolism of some lipoproteins by affecting the rate of their catabolism. Modifications of GAG pattern have been described in a few pathological conditions such as mucopolysaccharidosis, connective tissue diseases and kidney diseases. A high frequency of accelerated atherosclerosis has been observed in haemodialysis patients (HD), probably associated with the altered lipoprotein profile, which is often described in these subjects. Since GAGs may play a role in lipoprotein metabolism, we isolated and characterized plasma GAGs from a group of HD patients and a group of normal matched subjects. Quantitative analysis of plasma GAGs showed a significant increase of these polysaccharides in the HD group. Circulating levels of GAGs were 8.21 +/- 1.89 micrograms/ml in control subjects, and 15.08 +/- 3.13 micrograms/ml in the HD group (p < 0.0001). The isolation of plasma GAGs by ion-exchange chromatography produced two uronic acid containing families: a low-charge (peak I) and a high-charge (peak II) species. Both of these contained GAGs associated with plasma proteins.(ABSTRACT TRUNCATED AT 250 WORDS)     

Shade as a thermoregulatory resource for captive chimpanzees

In nature, the thermoregulatory strategies of species have evolved in response to the environmental conditions in which they live. Primates display extensive behavioural flexibility but few have examined the role of this behavioural flexibility with regard to thermoregulation. Chimpanzees, under free-living conditions, utilise natural vertical light/thermal gradients in rainforest canopies as a means of thermoregulation, moving along the gradient to maintain homoeostasis. In contrast, captive chimpanzees are often housed at latitudes outside their natural range under conditions that do not allow for this natural behavioural thermoregulation. We investigated the use of shade by captive chimpanzees as a behavioural thermoregulatory strategy at the Johannesburg Zoo, South Africa. We performed behavioural observations over the austral winter/spring period on a group of captive chimpanzees recording their behaviour in relation to shade use. Despite experiencing temperatures in Johannesburg below or just within their thermoneutral zone, chimpanzees consistently spent more time in shade than in direct sun. This pattern of shade use was most pronounced for the hotter midday period than for other times, was not dependent on the overall availability of shade within the enclosure and was not predicted by mean daily or hourly temperatures nor thermal maxima or minima. Instead, ultraviolet radiation and humidity levels appear to predict the observed patterns of shade utilisation and these findings suggest that chimpanzees in captivity adopt a sun-avoidance strategy, possibly as a result of the rapid heat gain associated with their dark skin and pelage. The findings suggest that chimpanzees are flexible when responding to the thermal challenges associated with housing outside of their natural environment.     

Hydroxylamine reduction to ammonium by plant and cyanobacterial hemoglobins

Plants often face hypoxic stress as a result of flooding and waterlogged soils. During these periods, they must continue ATP production and nitrogen metabolism if they are to survive. The normal pathway of reductive nitrogen assimilation in non-legumes, nitrate, and nitrite reductase can be inhibited during low oxygen conditions that are associated with the buildup of toxic metabolites such as nitrite and nitric oxide, so the plant must also have a means of detoxifying these molecules. Compared to animal hemoglobins, plant and cyanobacterial hemoglobins are adept at reducing nitrite to nitric oxide under anaerobic conditions. Here we test their abilities to reduce hydroxylamine, a proposed intermediate of nitrite reductase, under anaerobic conditions. We find that class 1 rice nonsymbiotic hemoglobin (rice nsHb1) and the hemoglobin from the cyanobacterium Synechocystis (SynHb) catalyze the reduction of hydroxylamine to ammonium at rates 100-2500 times faster than animal hemoglobins including myoglobin, neuroglobin, cytoglobin, and blood cell hemoglobin. These results support the hypothesis that plant and cyanobacterial hemoglobins contribute to anaerobic nitrogen metabolism in support of anaerobic respiration and survival during hypoxia.     

Biosynthesis and trafficking of seven transmembrane receptor signalling complexes

Recent studies have shown that 7-transmembrane receptors (7TM-Rs), their associated signalling molecules and scaffolding proteins are often constitutively associated under basal conditions. These studies highlight that receptor ontogeny and trafficking are likely to play key roles in the determination of both signalling specificity and efficacy. This review highlights information about how 7TM-Rs and their associated signalling molecules are trafficked to the cell surface as well as other intracellular destinations.     

Why can't a cell grow infinitely fast?

Living cells are esoteric physiochemical systems that have evolved to survive and reproduce in their naturl environment. Under balanced conditions of growth, bacteria are probably systems as simple as any kind of free-living organism. Evolutionary forces, seemingly, should have driven prokaryotes to be very efficient. In part that is so; they make effective use of the machinery most expensive for the cell, i.e., the ribosomes and associated factors. But the evidence is that the efficiency with which they use the ribosomal machinery increases as the environment provides more favorable conditions for balanced growth. This article emphasizes the limitation to growth under optimal conditions. The role of fluctuations in the environment and the cost of accurate protein synthesis are discussed as reasons for the upper limit in obtainable specific growth rate.     

Growth to death in lizards

Abstract.— Negative relationships between growth rate and survival have been demonstrated in many organisms, often reflecting risks associated with increased foraging rates. More puzzling, however, are recent reports that rapid growth early in life may lower survival rates much later in life, presumably because fast-growing animals allocate resources among different body components in ways that later compromise their survival. If widespread, such delayed effects may modify our interpretation of the evolution of life histories and phenotypic plasticity. Previous reports of this phenomenon are derived mostly from laboratory studies, generally on rodents or humans. We provide the first evidence from an experimental study in the field: neonatal lizards were exposed to different thermal conditions in seminatural enclosures at two different elevations (within their natural thermal regime). This arrangement allowed relatively higher and lower levels of food intake, which modified the neonates' growth rates (because lizards at more benign thermal conditions could forage more frequently). When later released into the wild, the individuals that grew more rapidly as neonates experienced much higher mortality than did slower-growing conspecifics, regardless of the elevation at which they had been kept.     

Are Bans on Kidney Sales Unjustifiably Paternalistic?

This paper challenges the view that bans on kidney sales are unjustifiably paternalistic, that is, that they unduly deny people the freedom to make decisions about their own bodies in order to protect them from harm. I argue that not even principled anti‐paternalists need to reject such bans. This is because their rationale is not hard paternalism, which anti‐paternalists repudiate, but soft paternalism, which they in principle accept. More precisely, I suggest that their rationale is what Franklin Miller and Alan Wertheimer call ‘group soft paternalism’. Group soft paternalistic policies restrict the freedom of autonomous individuals, not for their own good (hard paternalism), but as an unavoidable consequence of seeking to protect other, non‐autonomous individuals from harms that they have not voluntarily chosen (soft paternalism). Group soft paternalism supports prohibiting kidney sales on three conditions: (1) that such sales are potentially harmful to vendors, (2) that many vendors would suffer impaired autonomy, and (3) that distinguishing between autonomous and non‐autonomous vendors and interfering only with the latter is unfeasible. I provide reasons for thinking that these conditions will often hold.     

Topographic Variation in Structure of Mixed-Conifer Forests Under an Active-Fire Regime

Management efforts to promote forest resiliency as climate changes have often used historical forest structure and composition to provide general guidance for fuels reduction and forest restoration treatments. However, it has been difficult to identify what stand conditions might be fire and drought resilient because historical data and reconstruction studies are generally limited to accurate estimates only of large, live tree density and composition. Other stand features such as smaller tree densities, dead wood, understory structure, regeneration, and fuel loads have been difficult to quantify, estimate how they may vary across a landscape, or assess how they would be affected by fire under current climate conditions. We sampled old-growth, mixed-conifer forests with at least two low-intensity fires within the last 65?years in 150 plots at 48 sample sites ranging over 400?km of the Sierra Nevada. Recent fire history had the strongest influence on understory conditions with small tree density decreasing and shrub cover increasing with the increased intensity and frequency of fire associated with upper-slope and ridge-top locations. In contrast, stand structures associated with large, overstory trees such as total basal area, canopy cover, and the abundance of large snags and logs increased in topographic locations associated with more mesic, productive sites regardless of fire history. In forests with restored fire regimes, topography, fire and their interaction influence productivity and burn intensity, creating the structural heterogeneity characteristic of frequent-fire forests.     

Are polyphenols antioxidants or pro-oxidants? What do we learn from cell culture and in vivo studies?

Diets rich in polyphenols are epidemiologically associated with lower risk of developing some age-related diseases in humans. This apparent disease-protective effect of polyphenols is often attributed to their powerful antioxidant activities, as established in vitro. However, polyphenols can also exert pro-oxidant activities under certain experimental conditions. Neither pro-oxidant nor anti-oxidant activities have yet been clearly established to occur in vivo in humans, nor are they likely given the limited levels of polyphenols that are achievable in vivo after consumption of foods and beverages rich in them. Other actions of polyphenols may be more important in vivo. Many studies of the biological effects of polyphenols in cell culture have been affected by their ability to oxidise in culture media, and awareness of this problem can avoid erroneous claims.     

Myzostomida: a link between trochozoans and flatworms?

Myzostomids are obligate symbiotic invertebrates associated with echinoderms with a fossil record that extends to the Ordovician period. Due to their long history as host-specific symbionts, myzostomids have acquired a unique anatomy that obscures their phylogenetic affinities to other metazoans: they are incompletely segmented, parenchymous, acoelomate organisms with chaetae and a trochophore larva. Today, they are most often classified within annelids either as an aberrant family of polychaetes or as a separate class. We inferred the phylogenetic position of the Myzostomida by analysing the DNA sequences of two slowly evolving nuclear genes: the small subunit ribosomal RNA and elongation factor-1alpha. All our analyses congruently indicated that myzostomids are not annelids but suggested instead that they are more closely related to flatworms than to any trochozoan taxon. These results, together with recent analyses of the myzostomidan ultrastructure, have significant implications for understanding the evolution of metazoan body plans, as major characters (segmentation, coeloms, chaetae and trochophore larvae) might have been independently lost or gained in different animal phyla.     

Most and Least Preferred Colours Differ According to Object Context: New Insights from an Unrestricted Colour Range

Humans like some colours and dislike others, but which particular colours and why remains to be understood. Empirical studies on colour preferences generally targeted most preferred colours, but rarely least preferred (disliked) colours. In addition, findings are often based on general colour preferences leaving open the question whether results generalise to specific objects. Here, 88 participants selected the colours they preferred most and least for three context conditions (general, interior walls, t-shirt) using a high-precision colour picker. Participants also indicated whether they associated their colour choice to a valenced object or concept. The chosen colours varied widely between individuals and contexts and so did the reasons for their choices. Consistent patterns also emerged, as most preferred colours in general were more chromatic, while for walls they were lighter and for t-shirts they were darker and less chromatic compared to least preferred colours. This meant that general colour preferences could not explain object specific colour preferences. Measures of the selection process further revealed that, compared to most preferred colours, least preferred colours were chosen more quickly and were less often linked to valenced objects or concepts. The high intra- and inter-individual variability in this and previous reports furthers our understanding that colour preferences are determined by subjective experiences and that most and least preferred colours are not processed equally.     

Human cancer cell lines: fact and fantasy

Cancer cell lines are used in many biomedical research laboratories. Why, then, are they often described as unrepresentative of the cells from which they were derived? Here, I argue that they have been unjustly accused. Under the right conditions, and with appropriate controls, properly authenticated cancer cell lines retain the properties of the cancers of origin.     

ON USING PEOPLE MERELY AS A MEANS IN CLINICAL RESEARCH

It is often argued that clinical research should not violate the Kantian principle that people must not be used merely as a means for the purposes of others. At first sight, the practice of clinical research itself, however, seems to violate precisely this principle: clinical research is often beneficial to future people rather than to participants; even if participants benefit, all things considered, they are exposed to discomforts which are absent both in regular care for their diseases and in other areas of daily life. Therefore, in this paper we will consider whether people are used merely as a means by being enrolled in clinical research. On the basis of recent studies of Kantian scholars we will argue that clinical research is compatible with the Kantian principle if the conditions of possible consent and end‐sharing have been met. Participants are not used merely as a means if they have sufficient reasons to consent to being enrolled in clinical research and can share the ends of the researchers who use them. Moreover, we will claim that even if people are used merely as a means by participating in clinical research, it may not always be morally wrong to use them in this way.     

Phoretic mites associated with animal and human decomposition

Phoretic mites are likely the most abundant arthropods found on carcases and corpses. They outnumber their scavenger carriers in both number and diversity. Many phoretic mites travel on scavenger insects and are highly specific; they will arrive on a particular species of host and no other. Because of this, they may be useful as trace indicators of their carriers even when their carriers are absent. Phoretic mites can be valuable markers of time. They are usually found in a specialised transitional transport or dispersal stage, often moulting and transforming to adults shortly after arrival on a carcase or corpse. Many are characterised by faster development and generation cycles than their carriers. Humans are normally unaware, but we too carry mites; they are skin mites that are present in our clothes. More than 212 phoretic mite species associated with carcases have been reported in the literature. Among these, mites belonging to the Mesostigmata form the dominant group, represented by 127 species with 25 phoretic mite species belonging to the family Parasitidae and 48 to the Macrochelidae. Most of these mesostigmatids are associated with particular species of flies or carrion beetles, though some are associated with small mammals arriving during the early stages of decomposition. During dry decay, members of the Astigmata are more frequently found; 52 species are phoretic on scavengers, and the majority of these travel on late-arriving scavengers such as hide beetles, skin beetles and moths. Several species of carrion beetles can visit a corpse simultaneously, and each may carry 1–10 species of phoretic mites. An informative diversity of phoretic mites may be found on a decaying carcass at any given time. The composition of the phoretic mite assemblage on a carcass might provide valuable information about the conditions of and time elapsed since death.     

Living krill,zooplankton and experimental investigations: a discourse on the role of krill and their experimental study in marine ecology

Krill occupy critical positions in a many marine ecosystems and have been the subject of a number of concerted studies yet there are large areas of their biology that still remain a mystery. Most species of krill are open ocean animals, which makes direct observation and sampling difficult. Krill also exhibit a number of physiological and behavioural attributes which frustrate attempts to understand their life history. Krill are conceptually difficult to come to terms with; they are obviously different from larger marine organisms such as squid, fish, whales and fish yet they are also quite distinct from those animals classed as zooplankton such as copepods. Despite these differences they have most often been grouped with zooplankton and have been studied using techniques developed for animals which are orders of magnitude smaller than they. This mismatch has affected our view of their interactions with the physical world and also affects their perceived trophic interactions. Their size and mobility also interferes with our ability to sample them effectively and thus to develop our appreciation of their true role in the marine ecosystem. Understanding how intermediate-sized animals, such as krill, function in aquatic ecosystem is critical to better management of the marine environment.     

The teaching house officer

Although medical students on clinical ward rotations receive a large part of their education from house officers, very often house officers themselves have had little formal preparation as teachers. Because students and teachers work closely together under special conditions, unique educational situations are created where much more than factual information is conveyed. Although some house officers are "natural" teachers, others find such activities uncomfortable or burdensome. Most people, however, can be taught to be effective teachers, and preparation for teaching and teaching itself are beneficial for house officers and their patients as well as their students. House officers who teach enjoy the rewards that all teachers know as well as several others which are particular to the setting in which they teach. Mechanisms are suggested to maintain and develop interest in house staff teaching.     

Living krill, zooplankton and experimental investigations: a discourse on the role of krill and their experimental study in marine ecology

Krill occupy critical positions in a many marine ecosystems and have been the subject of a number of concerted studies yet there are large areas of their biology that still remain a mystery. Most species of krill are open ocean animals, which makes direct observation and sampling difficult. Krill also exhibit a number of physiological and behavioural attributes which frustrate attempts to understand their life history. Krill are conceptually difficult to come to terms with; they are obviously different from larger marine organisms such as squid, fish, whales and fish yet they are also quite distinct from those animals classed as zooplankton such as copepods. Despite these differences they have most often been grouped with zooplankton and have been studied using techniques developed for animals which are orders of magnitude smaller than they. This mismatch has affected our view of their interactions with the physical world and also affects their perceived trophic interactions. Their size and mobility also interferes with our ability to sample them effectively and thus to develop our appreciation of their true role in the marine ecosystem. Understanding how intermediate-sized animals, such as krill, function in aquatic ecosystem is critical to better management of the marine environment.     

Thermophilic nucleoside phosphorylases: Their properties,characteristics and applications

Nucleoside phosphorylases catalyze the reversible phosphorolysis of pyrimidine and purine nucleosides in the presence of phosphate. They are valuable catalysts in the synthesis of nucleosides and their analogues, which are often used as pharmaceuticals or their precursors. Thermostable nucleoside phosphorylases are promising biocatalysts, as they withstand harsh reaction conditions such as high pH or the addition of organic solvents. In this review, the characteristics and properties of thermostable nucleoside phosphorylases are described. Differences in amino acid content and protein structure were compared to their mesophilic homologues to identify features involved in thermostability. Substrate spectra of thermostable nucleoside phosphorylases were analyzed, and it is shown that thermostable nucleoside phosphorylases have a wider substrate spectrum than their mesophilic counterparts. Thus, thermostable nucleoside phosphorylases are interesting biocatalysts for industrial applications.