Photochemistry of Coordination Compounds of the Main Group Metals

A general concept is developed which relates characteristics excited states of main group metal complexes to typical photoreactions. With regard to their electronic spectra and photochemistry the main group metals are classified according to their ground state electron configuration nsxnpy. The photochemistry is generally dominated by the reactivity of metal-centered sp and ligand to metal charge transfer excited states which in most cases initiate inter- and intramolecular photoredox processes

Pattern Avoidance in Task-Precedence Posets

We have extended classical pattern avoidance to a new structure: multiple task-precedence posets whose Hasse diagrams have three levels, which we will call diamonds. The vertices of each diamond are assigned labels which are compatible with the poset. A corresponding permutation is formed by reading these labels by increasing levels, and then from left to right. We used Sage to form enumerative conjectures for the associated permutations avoiding collections of patterns of length three, which we then proved. We have discovered a bijection between diamonds avoiding 132 and certain generalized Dyck paths. We have also found the generating function for descents, and therefore the number of avoiders, in these permutations for the majority of collections of patterns of length three. An interesting application of this work (and the motivating example) can be found when task-precedence posets represent warehouse package fulfillment by robots, in which case avoidance of both 231 and 321 ensures we never stack two heavier packages on top of a lighter package.Comment: 17 page

Digit ratio (2D:4D) and its behavioral correlates in infant rhesus macaques (Macaca mulatta)

2D:4D ratios are typically lower in adult human males than females and are linked to numerous sex-differentiated behaviors. 2D:4D digit ratios are considered an indicator of prenatal androgen exposure; if so, children’s 2D:4D ratios would arguably be even better indicators of prenatal androgen exposures since children have experienced fewer postnatal influences than adults. However, sex differences in 2D:4D ratios as well as associations between 2D:4D ratios and sex-typed behaviors in children have been inconsistent. Several studies also report sex differences and behavioral correlates of 2D:4D ratios in adult non-human primates, but little is known about 2D:4D ratios in infant non-human primates. The current study examined sex differences in 2D:4D ratios over the first month of life, and associations with behavioral outcomes at 12-24 weeks of age, in N=304 infant rhesus macaques. An increase in 2D:4D ratios over the first month of life was found, as well as associations with aggression and play behaviors, but no sex differences in 2D:4D ratios were observed. These results highlight the need for future developmental studies of 2D:4D ratios in order to determine not only their stability and predictive value, but also to discern the mechanism connecting prenatal androgen exposure, 2D:4D ratios, and behavioral outcomes

Ein Regulationsnetzwerk aus H-NS und den Antirepressoren BglJ und LeuO

Das Nukleoid-assoziierte Protein H-NS steuert als globaler Repressor 200 bis 300 der Gene von Escherichia coli. Die Repression eines dieser Loci, des bgl-Operons (aryl-beta,D-Glukosid Operon) ist ungewoehnlich strikt und erfolgt durch Bindung von H-NS an zwei regulatorische Regionen oberhalb und unterhalb des Promotors. Die strikte Repression ist die Ursache dafuer, dass das bgl-Operon kryptisch ist, d.h. es wird unter Labor-ueblichen Wachstumsbedingungen nicht exprimiert. Allerdings fuehrt die Ueberexpression der Transkriptionsfaktoren LeuO und BglJ zu einem Bgl+ Phaenotyp. In dieser Arbeit wurde gezeigt, dass LeuO und BglJ als Anti-Repressoren von H-NS wirken. LeuO und BglJ heben die Repression durch Bindung von H-NS oberhalb des Promotors auf. Bindestudien zeigen, dass LeuO direkt an die 5'-bgl-Promotorregion bindet und dadurch den H-NS-Repressionskomplex moduliert. Ein Screen nach Mutanten sowie Expressionsanalysen zeigten, dass die Aktivierung des bgl-Promotors durch BglJ von RcsB abhaengig ist. RcsB ist der Response-Regulator des Rcs-Phosphorelaysystems, eines der drei Membranstress-Sensing-Systeme von E.coli. BglJ und RcsB gehoeren zur selben Familie der LuxR-aehnlichen Transkriptionsfaktoren und bilden im Two-Hybrid-System Heterodimere. Daher ist anzunehmen, dass ein BglJ/RcsB-Heterodimer als Anti-Repressor im bgl-Promotorbereich bindet und den Promotor aktiviert. Beim Versuch BglJ und RcsB für in-vitro-Interaktionsanalysen und DNA-Bindestudien zu exprimieren, zeigte sich, dass RcsB die Stabilitaet von BglJ vermindert. RcsB ist also einerseits für die Aktivierung von bgl durch BglJ notwendig und reguliert andererseits BglJ negativ. H-NS, LeuO und BglJ bilden ein komplexes Netzwerk. Die Antirepressoren LeuO und BglJ heben die Repression von bgl durch H-NS auf. Die leuO und bglJ-Gene werden aber selbst durch H-NS reprimiert, wobei LeuO wiederum Aktivator von bglJ ist. Dieses Regulationsnetzwerk wird ergaenzt durch den Response-Regulator RcsB, der für die bgl-Aktivierung durch BglJ notwendig ist. Die Komplexitaet der Wechselwirkungen legt nahe, dass die Aktivierung von bgl in vivo an streng definierte Bedingungen geknuepft ist, wobei ueber RcsB eine moegliche Verbindung zu Membranstress hergestellt wird und LeuO auf Aminosaeuremangel als Signal hinweist

Secondary representational abilities in nonhuman primates (Macaca nemestrina, Cebus apella)

As human infants mature, their cognitive operations achieve increasing levels of complexity, which is thought to be based on an increasing complexity of their mental representational abilities. Perner (1991) proposed three different types of mental representations that are believed to underlie this development: primary representations, which represent reality accurately and faithfully; secondary representations, which are ‘detached’ from immediate reality and therefore capable of modelling past or future situations; and metarepresentations, which explicitly represent the relationship between the representation and its content. Numerous studies have provided evidence that in humans, primary representations appear to be present from birth, secondary representations emerge between 1.5-2 years, and metarepresentations develop between 4.5-5 years. Much less is known with regard to the phylogenetic development of representational abilities. Studies with nonhuman primates suggest the presence of primary and secondary representational abilities in great apes, but only primary representational abilities in monkeys. However, the current lack of evidence for secondary representational abilities in monkeys might be related to the limited number of studies addressing this issue and/or methodological limitations, thereby perhaps not reflecting a true negative. In order to contribute towards a more complete picture of nonhuman primates’ representational abilities, a series of studies was conducted to examine secondary representational abilities in two monkey species (Macaca nemestrina, Cebus apella). Pig-tailed macaques were tested for self-imitation, imitation recognition and mirror self-recognition; capuchin monkeys were tested for imitation recognition, mirror self-recognition and means-ends reasoning, all thought to be indicative of secondary representational abilities. Evidence for primary representations was found in both species, however none of the experiments provided strong evidence for secondary representational abilities. One possible exception is two pig-tailed macaques’ responses to marks on their heads during a classic mark test for self-recognition, but since these responses consisted of mere swipes to their heads and not intensive mirror-mediated responding, this finding cannot be regarded as conclusive. The absence of evidence for secondary representational abilities in monkeys in the present work therefore confirms previous research findings and may suggest that monkeys are limited to primary representational abilities. Replications and extensions of the present work are highly recommended and can significantly contribute to our understanding of the evolutionary origin of human and nonhuman primate cognition

Sex differences in play behavior in juvenile tufted capuchin monkeys (Cebus apella)

According to the motor training hypothesis, play behavior in juvenile primates improves motor skills that are required in later adult life. Sex differences in juvenile play behavior can therefore be expected when adult animals assume distinct sexually dimorphic roles. Tufted capuchin monkeys show sexually dimorphic levels of physical antagonism in both inter- and intragroup encounters. Accordingly, it can be predicted that juvenile capuchins also show sex differences in social play behavior. To test this hypothesis, the play behavior of nine juvenile and two infant capuchins was examined. As predicted, juvenile males showed significantly higher levels of social play (wrestle, chase) than juvenile females, but no differences were found in nonsocial play (arboreal, object). Levels of infant play behavior were comparable to that of juveniles. These results lend support to the motor training hypothesis and highlight the need for more detailed investigations of individual differences in play behavior

Cued repetition of self-directed behaviors in macaques (Macaca nemestrina)

Two macaques were trained to perform three self-directed behaviors on signal, and to repeat behaviors after a ‘repeat’ signal. The cognitive processes underlying the monkeys’ repeat performance were evaluated using multiple repetitions of the repeat signal, extended delay periods between target behavior and repeat signal, and by transferring the repeat signal to novel behaviors. The monkeys appear to have used representations of their own past behaviors as a basis for repetition performance, but they mostly failed to correctly repeat target behaviors after extended delays and during transfer tasks. Implications for episodic memory abilities are discussed

Expression, purification, and characterization of galactose oxidase of Fusarium sambucinum in E. coli

AbstractA gene encoding a galactose oxidase (GalOx) was isolated from Fusarium sambucinum cultures and overexpressed in Escherichia coli yielding 4.4mg enzyme per L of growth culture with a specific activity of 159Umg−1. By adding a C-terminal His-tag the enzyme could be easily purified with a single affinity chromatography step with high recovery rate (90%). The enzyme showed a single band on SDS–PAGE with an apparent molecular mass of 68.5kDa. The pH optimum for the oxidation of galactose was in the range of pH 6–7.5. Optimum temperature for the enzyme activity was 35°C, with a half-life of 11.2min, 5.3min, and 2.7min for incubation at 40°C, 50°C, and 60°C, respectively. From all tested substrates, the highest relative activity was found for 1-methyl-β-galactopyranoside (226Umg−1) and the highest catalytic efficiency (kcat/Km) for melibiose (2700mM−1s−1). The enzyme was highly specific for molecular oxygen as an electron acceptor, and showed no appreciable activity with a range of alternative acceptors investigated. Different chemicals were tested for their effect on GalOx activity. The activity was significantly reduced by EDTA, NaN3, and KCN