Bats Use Magnetite to Detect the Earth's Magnetic Field

While the role of magnetic cues for compass orientation has been confirmed in numerous animals, the mechanism of detection is still debated. Two hypotheses have been proposed, one based on a light dependent mechanism, apparently used by birds and another based on a “compass organelle” containing the iron oxide particles magnetite (Fe3O4). Bats have recently been shown to use magnetic cues for compass orientation but the method by which they detect the Earth's magnetic field remains unknown. Here we use the classic “Kalmijn-Blakemore” pulse re-magnetization experiment, whereby the polarity of cellular magnetite is reversed. The results demonstrate that the big brown bat Eptesicus fuscus uses single domain magnetite to detect the Earths magnetic field and the response indicates a polarity based receptor. Polarity detection is a prerequisite for the use of magnetite as a compass and suggests that big brown bats use magnetite to detect the magnetic field as a compass. Our results indicate the possibility that sensory cells in bats contain freely rotating magnetite particles, which appears not to be the case in birds. It is crucial that the ultrastructure of the magnetite containing magnetoreceptors is described for our understanding of magnetoreception in animals

Towards an Evolutionary Computational Approach to Articulatory Vocal Synthesis with PRAAT

Abstract. This paper presents our current work into developing an evo-lutionary computing approach to articulatory speech synthesis. Specifi-cally, we implement genetic algorithms to find optimised parameter com-binations for the re-synthesis of a vowel using the articulatory synthesiser PRAAT. Our framework analyses the target sound using Fast Fourier Transform (FFT) to obtain formant information, which is then har-nessed in a fitness function applied to a real valued genetic algorithm using a generation size of 75 sounds over 50 generations. In this paper, we present three differently configured genetic algorithms (GAs) and of-fer a comparison of their suitability for elevating the average fitness of the re-synthesised sounds

Modelling Hurricane Exposure and Wind Speed on a Mesoclimate Scale: A Case Study from Cusuco NP, Honduras

High energy weather events are often expected to play a substantial role in biotic community dynamics and large scale diversity patterns but their contribution is hard to prove. Currently, observations are limited to the documentation of accidental records after the passing of such events. A more comprehensive approach is synthesising weather events in a location over a long time period, ideally at a high spatial resolution and on a large geographic scale. We provide a detailed overview on how to generate hurricane exposure data at a meso-climate level for a specific region. As a case study we modelled landscape hurricane exposure in Cusuco National Park (CNP), Honduras with a resolution of 50 m×50 m patches. We calculated actual hurricane exposure vulnerability site scores (EVVS) through the combination of a wind pressure model, an exposure model that can incorporate simple wind dynamics within a 3-dimensional landscape and the integration of historical hurricanes data. The EVSS was calculated as a weighted function of sites exposure, hurricane frequency and maximum wind velocity. Eleven hurricanes were found to have affected CNP between 1995 and 2010. The highest EVSS's were predicted to be on South and South-East facing sites of the park. Ground validation demonstrated that the South-solution (i.e. the South wind inflow direction) explained most of the observed tree damage (90% of the observed tree damage in the field). Incorporating historical data to the model to calculate actual hurricane exposure values, instead of potential exposure values, increased the model fit by 50%

α-Synuclein Aggregation Inhibitory Prunolides and a Dibrominated β-Carboline Sulfamate from the Ascidian Synoicum prunum

Seven new polyaromatic bis-spiroketal-containing butenolides, the prunolides D–I (4–9) and cis-prunolide C (10), a new dibrominated β-carboline sulfamate named pityriacitrin C (11), alongside the known prunolides A–C (1–3) were isolated from the Australian colonial ascidian Synoicum prunum. The prunolides D–G (4–7) represent the first asymmetrically brominated prunolides, while cis-prunolide C (10) is the first reported with a cis-configuration about the prunolide’s bis-spiroketal core. The prunolides displayed binding activities with the Parkinson’s disease-implicated amyloid protein α-synuclein in a mass spectrometry binding assay, while the prunolides (1–5 and 10) were found to significantly inhibit the aggregation (>89.0%) of α-synuclein in a ThT amyloid dye assay. The prunolides A–C (1–3) were also tested for inhibition of pSyn aggregate formation in a primary embryonic mouse midbrain dopamine neuron model with prunolide B (2) displaying statistically significant inhibitory activity at 0.5 μM. The antiplasmodial and antibacterial activities of the isolates were also examined with prunolide C (3) displaying only weak activity against the 3D7 parasite strain of Plasmodium falciparum. Our findings reported herein suggest that the prunolides could provide a novel scaffold for the exploration of future therapeutics aimed at inhibiting amyloid protein aggregation and the treatment of numerous neurodegenerative diseases.Peer reviewe

Fluid gels: a new feedstock for high viscosity jetting

Suspensions of gel particles which are pourable or spoonable at room temperature can be created by shearing a gelling biopolymer through its gelation (thermal or ion mediated) rather than allowing quiescent cooling – thus the term ‘fluid gel’ may be used to describe the resulting material. As agar gelation is thermoreversible this type of fluid gel is able to be heated again to melt agar gel particles to varying degrees then re-form a network quiescently upon cooling, whose strength depends on the temperature of re-heating, determining the amount of agar solubilised and subsequently able to partake in re-gelation. Using this principle, for the first time fluid gels have been applied to a high viscosity 3D printing process wherein the printing temperature (at the nozzle) is controllable. This allows the use of ambient temperature feedstocks and by altering the nozzle temperature, the internal nature (presence or absence of gel particles) and gel strength of printed droplets differs. If the nozzle prints at different temperatures for each layer a structure with modulated texture could be created

Surgery and transplantation – Guidelines on Parenteral Nutrition, Chapter 18

In surgery, indications for artificial nutrition comprise prevention and treatment of catabolism and malnutrition. Thus in general, food intake should not be interrupted postoperatively and the re-establishing of oral (e.g. after anastomosis of the colon and rectum, kidney transplantation) or enteral food intake (e.g. after an anastomosis in the upper gastrointestinal tract, liver transplantation) is recommended within 24 h post surgery. To avoid increased mortality an indication for an immediate postoperatively artificial nutrition (enteral or parenteral nutrition (PN)) also exists in patients with no signs of malnutrition, but who will not receive oral food intake for more than 7 days perioperatively or whose oral food intake does not meet their needs (e.g. less than 60–80%) for more than 14 days. In cases of absolute contraindication for enteral nutrition, there is an indication for total PN (TPN) such as in chronic intestinal obstruction with a relevant passage obstruction e.g. a peritoneal carcinoma. If energy and nutrient requirements cannot be met by oral and enteral intake alone, a combination of enteral and parenteral nutrition is indicated. Delaying surgery for a systematic nutrition therapy (enteral and parenteral) is only indicated if severe malnutrition is present. Preoperative nutrition therapy should preferably be conducted prior to hospital admission to lower the risk of nosocomial infections. The recommendations of early postoperative re-establishing oral feeding, generally apply also to paediatric patients. Standardised operative procedures should be established in order to guarantee an effective nutrition therapy

Home visit improves knowledge, self-care and adhesion in heart failure: randomized Clinical Trial HELEN-I

OBJECTIVE: To verify the effect of an educative nursing intervention composed of home visits and phone calls on patients' knowledge about the disease, self-care and adhesion to the treatment. METHODS: Randomized clinical trial with patients with recent hospitalization caused by decompensated heart failure. There were two groups: the intervention group, which has received four home visits and four phone calls to reinforce the guidelines during six months of follow up; and the control group, which has received conventional follow up with no visits or phone calls. RESULTS: Two hundred patients were randomized (101 in the intervention group and 99 in the control group). After six months, a significant improvement was observed in self-care and knowledge about the disease in the intervention group (P=0.001 and P<0.001), respectively; the adhesion to the treatment, measured and compared between the groups, was significantly higher in the intervention group (P=0.001). CONCLUSION: the strategy of home visits to patients who were recently hospitalized with decompensated heart failure was effective in improving the outcomes assessed and its implementation deserves to be considered in Brazil aiming at avoiding unplanned hospitalizations. NCT-0121386

A new efficient trial design for assessing reliability of ankle-brachial index measures by three different observer groups

BACKGROUND: The usual method of assessing the variability of a measure such as the ankle brachial index (ABI) as a function of different observer groups is to obtain repeated measurements. Because the number of possible observer-subject combinations is impractically large, only a few small studies on inter- and intraobserver variability of ABI measures have been carried out to date. The present study proposes a new and efficient study design. This paper describes the study methodology. METHODS: Using a partially balanced incomplete block design, six angiologists, six primary-care physicians and six trained medical office assistants performed two ABI measurements each on six individuals from a group of 36 unselected subjects aged 65–70 years. Each test subject is measured by one observer from each of the three observer groups, and each observer measures exactly six of the 36 subjects in the group. Each possible combination of two observers occurs exactly once per patient and is not repeated on a second subject. The study involved four groups of 36 subjects (144), plus standbys. RESULTS: The 192 volunteers present at the study day were similar in terms of demographic characteristics and vascular risk factors: mean age 68.6 ± 1.7; mean BMI 29.1 ± 4.6; mean waist-hip ratio 0.92 ± 0.09; active smokers 12%; hypertension 60.9%; hypercholesterolemia 53.4%; diabetic 17.2%. A complete set of ABI measurements (three observers performing two Doppler measurements each) was obtained from 108 subjects. From all other subjects at least one ABI measurement was obtained. The mean ABI was 1.08 (± 0.13), 15 (7.9%) volunteers had an ABI <0.9, and none had an ABI >1.4, i.e. a ratio that may be associated with increased stiffening of the arterial walls. CONCLUSION: This is the first large-scale study investigating the components of variability and thus reliability in ABI measurements. The advantage of the new study design introduced here is that only one sixth of the number of theoretically possible measurements is required to obtain information about measurement errors. Bland-Altman plots show that there are only small differences and no systematic bias between the observers from three occupational groups with different training backgrounds

The intraductal approach to the breast: raison d'être

Opportunities for the detection, prediction, and treatment of breast cancer exist at three biological levels: systemically via the blood, at the whole organ level, and within the individual ductal lobular structures of the breast. This review covers the evaluation of approaches targeted to the ductal lobular units, where breast cancer begins. Studies to date suggest the presence of 5 to 12 independent ductal lobular systems per breast, each harboring complex cellular fluids contributed by local and systemic processes. New techniques for accessing and interrogating these systems offer the potential to gauge the microenvironment of the breast and distill biological risk profiles