Determination of prey capture rates in the stony coral Galaxea fascicularis: a critical reconsideration of the clearance rate concept

In order to determine optimal feeding regimes for captive corals, prey capture by the scleractinian coral Galaxea fascicularis was determined by measuring clearance of prey items from the surrounding water. Colonies of G. fascicularis (sized between 200 and 400 polyps) were incubated in 1300 ml incubation chambers. Nauplii of the brine shrimp Artemia sp. were used as the prey item. A series of incubation experiments was conducted to determine the maximal capture per feeding event and per day. To determine maximal capture per feeding event, total uptake of nauplii after one hour was determined for different prey item availabilities ranging from 50 to 4000 nauplii per polyp. To determine maximal capture per day, the corals were subjected to four repetitive feeding events at three different prey item densities (50, 100 and 150 nauplii per polyp). Alongside these quantitative experiments, it was tested to what extent the feeding response of corals is triggered by chemical cues. One hour after food addition, extract of Artemia nauplii was added to the incubation chambers to test its effect on subsequent prey capture rates. In all experiments, prey capture was expressed as the number of nauplii consumed per coral polyp. Total capture of Artemia nauplii by G. fascicularis after a single feeding event increased linearly up till a prey item availability of 2000 nauplii per polyp. Maximal capture per feeding event was estimated at 1200 nauplii per polyp, which is higher than rates reported in previous studies. It became apparent that at high densities of Artemia nauplii, the clearance rate method does not discriminate between active capture and passive sedimentation. Repetitive feeding with 50 nauplii per polyp resulted in a constant total prey capture per feeding event. At a supply of 100 nauplii per polyp, total capture decreased after the first feeding event, and remained constant during the subsequent feeding events at a level comparable to the lower food availability. However, at a supply of 150 nauplii per polyp, total capture per event was higher throughout the entire four-hour incubation period, which obfuscates an accurate estimation of the maximal daily food uptake. In all incubations, a decrease in capture efficiency was observed within the course of the feeding event. In all repetitive feeding experiments, capture efficiency increased immediately upon addition of a new batch of food. This increase in efficiency was not caused by a priming effect of extract of Artemia. The inconsistencies in the data show that estimates of prey capture based on clearance rates should be interpreted with caution, because this method does not take into account potential dynamics of prey capture and release

An Epigenetics-Inspired DNA-Based Data Storage System.

Biopolymers are an attractive alternative to store and circulate information. DNA, for example, combines remarkable longevity with high data storage densities and has been demonstrated as a means for preserving digital information. Inspired by the dynamic, biological regulation of (epi)genetic information, we herein present how binary data can undergo controlled changes when encoded in synthetic DNA strands. By exploiting differential kinetics of hydrolytic deamination reactions of cytosine and its naturally occurring derivatives, we demonstrate how multiple layers of information can be stored in a single DNA template. Moreover, we show that controlled redox reactions allow for interconversion of these DNA-encoded layers of information. Overall, such interlacing of multiple messages on synthetic DNA libraries showcases the potential of chemical reactions to manipulate digital information on (bio)polymers.C.M. is grateful for the financial support by the Swiss National Science Foundation (grant number P2EZP2_152216). G.R.M. was supported by funding from Trinity College, Cambridge, the Herchel Smith fund and the Wellcome Trust. P.M. was funded by the Wellcome Trust and is currently supported by an ERC Advanced grant. P.V.D was funded by the Wellcome Trust and a Marie Curie Fellow of the European Union (grant number FP7-PEOPLE-2013-IEF/624885). The S.B. lab is supported by a program grant and core funding from Cancer Research UK (C9681/A18618), an ERC Advanced grant (339778) and by a Senior Investigator Award of the Wellcome Trust (099232/Z/12/Z). We thank Eun-Ang Raiber and Dario Beraldi for stimulating discussions and proofreading the manuscript.This is the final version of the article. It first appeared from Wiley at http://dx.doi.org/10.1002/anie.201605531

The impact of short-selling in financial markets

This dissertation empirically examines the impact of short-selling in financial markets. Given the increasing participation of short-sellers in financial markets, this research provides empirical evidence on an increasingly important issue. Each chapter addresses a research question with scarce or conflicting prior research findings to provide evidence which can assist researchers, investors and regulators to understand and manage the impact of short-selling in financial markets

New Measures for Predicting Birth-Related Pelvic Floor Trauma.

OBJECTIVES: The aim of this study was to establish the predictive role of obstetric variables for obstetric outcomes and birth related levator ani muscle (LAM) trauma. METHODS: In this prospective study, women underwent 3-dimensional pelvic floor ultrasound at their first appointment at 36 weeks and also 3 months postpartum. The measurements included minimal levator hiatus circumference (MLHC) and the ratio of fetal head circumference to MLHC = head-induced stretch ratio (HISR) as an indicator of the discrepancy between passage and passing canal. To derive the true impact of baby's mass on the levator ani musculature, we devised the levator ani stretch ratio (LASR), which was calculated by multiplying the HISR and the baby's weight. RESULTS: Data set of 173 women was available for analysis. Mean HISR and LASR values were statistically different across all binary outcome categories, with 1 exception for HISR and levator ani injury. The odds ratios for LASR indicated positive and statistically significant associations with all obstetric outcomes examined. The probability of the LASR correctly classifying those with the adverse obstetric outcome, as estimated by the area under the curve, ranged from 0.64 to 0.80 with the strongest discriminatory ability observed for severe LAM trauma. CONCLUSIONS: Fetal head circumference/mother MLHC ratio (HISR) is associated with longer length of second stage of labor, assisted delivery, and increased severity of perineal trauma. Similar associations were observed for LASR, but in addition, LASR had good discriminatory ability to identify severe LAM trauma

Nonsaturating magnetoresistance and nontrivial band topology of type-II Weyl semimetal NbIrTe4

Weyl semimetals, characterized by nodal points in the bulk and Fermi arc states on the surface, have recently attracted extensive attention due to the potential application on low energy consumption electronic materials. In this report, the thermodynamic and transport properties of a theoretically predicted Weyl semimetal NbIrTe4 is measured in high magnetic fields up to 35 T and low temperatures down to 0.4 K. Remarkably, NbIrTe4 exhibits a nonsaturating transverse magnetoresistance which follows a power-law dependence in B. Low-field Hall measurements reveal that hole-like carriers dominate the transport for T $>$ 80 K, while the significant enhancement of electron mobilities with lowering T results in a non-negligible contribution from electron-like carriers which is responsible for the observed non-linear Hall resistivity at low T. The Shubnikov-de Haas oscillations of the Hall resistivity under high B give the light effective masses of charge carriers and the nontrivial Berry phase associated with Weyl fermions. Further first-principles calculations confirm the existence of 16 Weyl points located at kz = 0, $\pm$0.02 and $\pm$0.2 planes in the Brillouin zone.Comment: 5 figures, 1 tabl