Ultraviolet absorbing compounds provide a rapid response mechanism for UV protection in some reef fish.

The external mucus surface of reef fish contains ultraviolet absorbing compounds (UVAC), most prominently Mycosporine-like Amino Acids (MAAs). MAAs in the external mucus of reef fish are thought to act as sunscreens by preventing the damaging effects of ultraviolet radiation (UVR), however, direct evidence for their protective role has been missing. We tested the protective function of UVAC's by exposing fish with naturally low, Pomacentrus amboinensis, and high, Thalassoma lunare, mucus absorption properties to a high dose of UVR (UVB: 13.4W∗m(-2), UVA: 6.1W∗m(-2)) and measuring the resulting DNA damage in the form of cyclobutane pyrimidine dimers (CPDs). For both species, the amount of UV induced DNA damage sustained following the exposure to a 1h pulse of high UVR was negatively correlated with mucus absorbance, a proxy for MAA concentration. Furthermore, a rapid and significant increase in UVAC concentration was observed in P. amboinensis following UV exposure, directly after capture and after ten days in captivity. No such increase was observed in T. lunare, which maintained relatively high levels of UV absorbance at all times. P. amboinensis, in contrast to T. lunare, uses UV communication and thus must maintain UV transparent mucus to be able to display its UV patterns. The ability to rapidly alter the transparency of mucus could be an important adaptation in the trade off between protection from harmful UVR and UV communication.CB was funded by a research grant by the SeaWorld Research and Rescue Foundation to UES and CB and a UQ International Fellowship (UQI). UES was funded by the Australian Research Council (DP140100431).This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.jphotobiol.2016.04.02

Learning to diagnose accurately through virtual patients: do reflection phases have an added benefit?

BACKGROUND Simulation-based learning with virtual patients is a highly effective method that could potentially be further enhanced by including reflection phases. The effectiveness of reflection phases for learning to diagnose has mainly been demonstrated for problem-centered instruction with text-based cases, not for simulation-based learning. To close this research gap, we conducted a study on learning history-taking using virtual patients. In this study, we examined the added benefit of including reflection phases on learning to diagnose accurately, the associations between knowledge and learning, and the diagnostic process. METHODS A sample of N = 121 medical students completed a three-group experiment with a control group and pre- and posttests. The pretest consisted of a conceptual and strategic knowledge test and virtual patients to be diagnosed. In the learning phase, two intervention groups worked with virtual patients and completed different types of reflection phases, while the control group learned with virtual patients but without reflection phases. The posttest again involved virtual patients. For all virtual patients, diagnostic accuracy was assessed as the primary outcome. Current hypotheses were tracked during reflection phases and in simulation-based learning to measure diagnostic process. RESULTS Regarding the added benefit of reflection phases, an ANCOVA controlling for pretest performance found no difference in diagnostic accuracy at posttest between the three conditions, F(2, 114) = 0.93, p = .398. Concerning knowledge and learning, both pretest conceptual knowledge and strategic knowledge were not associated with learning to diagnose accurately through reflection phases. Learners' diagnostic process improved during simulation-based learning and the reflection phases. CONCLUSIONS Reflection phases did not have an added benefit for learning to diagnose accurately in virtual patients. This finding indicates that reflection phases may not be as effective in simulation-based learning as in problem-centered instruction with text-based cases and can be explained with two contextual differences. First, information processing in simulation-based learning uses the verbal channel and the visual channel, while text-based learning only draws on the verbal channel. Second, in simulation-based learning, serial cue cases are used to gather information step-wise, whereas, in text-based learning, whole cases are used that present all data at once

Natural history, clinical pattern, and surgical considerations of pneumatosis intestinalis

<p>Abstract</p> <p>Objective</p> <p>Pneumatosis intestinalis has been increasingly detected in recent years with the more frequent use of computed tomography for abdominal imaging of the intestine. The underlying causes of the gas found during radiographic studies of the bowel wall can vary widely and different hypotheses regarding its pathophysiology have been postulated. Pneumatosis intestinalis often represents a benign condition and should not be considered an argument for surgery. However, it can also require life-threatening surgery in some cases, and this can be a difficult decision in some patients.</p> <p>Methods</p> <p>The spectrum of pneumatosis intestinalis is discussed here based on various computed tomographic and surgical findings in patients who presented at our University Medical Centre in 2003-2008. We have also systematically reviewed the literature to establish the current understanding of its aetiology and pathophysiology, and the possible clinical conditions associated with pneumatosis intestinalis and their management.</p> <p>Results</p> <p>Pneumatosis intestinalis is a primary radiographic finding. After its diagnosis, its specific pathogenesis should be ascertained because the appropriate therapy is related to the underlying cause of pneumatosis intestinalis, and this is sometimes difficult to define. Surgical treatment should be considered urgent in symptomatic patients presenting with an acute abdomen, signs of ischemia, or bowel obstruction. In asymptomatic patients with otherwise inconspicuous findings, the underlying disease should be treated first, rather than urgent exploratory surgery considered. Extensive and comprehensive information on the pathophysiology and clinical findings of pneumatosis intestinalis is provided here and is incorporated into a treatment algorithm.</p> <p>Conclusions</p> <p>The information presented here allows a better understanding of the radiographic diagnosis and underlying aetiology of pneumatosis intestinalis, and may facilitate the decision-making process in this context, thus providing fast and adequate therapy to particular patients.</p

The periodicity of phytoplankton in Lake Constance (Bodensee) in comparison to other deep lakes of central Europe

Phytoplankton periodicity has been fairly regular during the years 1979 to 1982 in Lake Constance. Algal mass growth starts with the vernal onset of stratification; Cryptophyceae and small centric diatoms are the dominant algae of the spring bloom. In June grazing by zooplankton leads to a lsquoclear-water phasersquo dominated by Cryptophyceae. Algal summer growth starts under nutrient-saturated conditions with a dominance of Cryptomonas spp. and Pandorina morum. Depletion of soluble reactive phosphorus is followed by a dominance of pennate and filamentous centric diatoms, which are replaced by Ceratium hirundinella when dissolved silicate becomes depleted. Under calm conditions there is a diverse late-summer plankton dominated by Cyanophyceae and Dinobryon spp.; more turbulent conditions and silicon resupply enable a second summer diatom growth phase in August. The autumnal development leads from a Mougeotia — desmid assemblage to a diatom plankton in late autumn and winter. Inter-lake comparison of algal seasonality includes in ascending order of P-richness Königsee, Attersee, Walensee, Lake Lucerne, Lago Maggiore, Ammersee, Lake Zürich, Lake Geneva, Lake Constance. The oligotrophic lakes have one or two annual maxima of biomass; after the vernal maximum there is a slowly developing summer depression and sometimes a second maximum in autumn. The more eutrophic lakes have an additional maximum in summer. The number of floristically determined successional stages increases with increasing eutrophy, from three in Königsee and Attersee to eight in Lake Geneva and Lake Constance

Search for proton emission of the isomeric 10+ state in 54 Ni

9 pags., 7 figs., 1 tab.Several experiments were conducted at the 10 MV Van-de-Graaff tandem accelerator at the Institute of Nuclear Physics, Cologne, to detect proton emission from the isomeric 6457-keV 10 state in Ni. Excitation functions for two fusion–evaporation reactions were measured to maximise the population of the rare two-neutron evaporation channel from a Ni compound nucleus. The search for delayed proton emission was based on the Si (Si , 2 n)Ni reaction at a beam energy of 70 MeV. For this reaction, a cross-section limit for the population of the 10 state in Ni and its proton-decay branch was determined to be σ< 22 nb.Open Access funding provided by Projekt DEAL. We would like to thank the accelerator staff at the University of Cologne for the efforts to deliver heavy-ion beams of excellent quality, as well as the Swedish Research Council (contract VR 2008-4240 and VR 2016- 3969) for financial support

Quadrupole collectivity in neutron-rich Cd isotopes

4 pags., 2 figs. -- INPC 2013 – International Nuclear Physics ConferenceThe investigation of the excitation energies of the 21+ –states in the neutron-rich Cd isotopes shows an irregular behaviour when approaching the neutron shell-closure at N = 82. The energy of the 21+–state in 128Cd is lower than the one in 126Cd. The transition strength B(E2, 0gs+ → 21+) in the even isotopes 122−128Cd was measured in Coulomb excitation experiments with the high-purity germanium detector array MINIBALL at REXISOLDE (CERN). The values for 122,124Cd coincide with beyond-mean-field calculations with a resultant prolate deformation, whereas 126,128Cd are better described by shell-model calculations.This project is supported by BMBF (No. 06 DA 9036I, No. 05 P12 RDCIA, No. 05 P12 RDCIB and No. 05 P12 PKFNE), HIC for FAIR, EU through EURONS (No. 506065) and ENSAR (No. 262010) and the MINIBALL and REX-ISOLDE collaborations

No evidence for UV-based nest-site selection in sticklebacks

BACKGROUND: Nests are built in various animal taxa including fish. In systems with exclusive male parental care, the choice of a nest site may be an important component of male fitness. The nest site may influence male attractiveness as a mate, and male, embryo, and juvenile survival probabilities. Reproductively active three-spined stickleback males establish and defend a territory in which they build a nest. Territories can differ remarkably in qualities that influence male and female reproductive success like predation risk or abiotic factors such as dissolved oxygen concentration or lighting conditions. The latter may be important because in sticklebacks the extended visual capability into the ultraviolet (UV) wave range plays a role in female mate choice. Males are thus expected to be choosy about the habitat in which they will build their nest. RESULTS: We tested nest-site choice in male three-spined sticklebacks with respect to different UV lighting conditions. Reproductively active males were given the simultaneous choice to build their nest either in an UV-rich (UV+) or an UV-lacking (UV-) environment. Males exhibited no significant nest-site preferences with respect to UV+ or UV-. However, larger males and also heavier ones completed their nests earlier. CONCLUSION: We found that UV radiation as well as differences in luminance had no influence on nest-site choice in three-spined sticklebacks. Males that built in the UV-rich environment were not different in any trait (body traits and UV reflection traits) from males that built in the UV-poor environment. There was a significant effect of standard length and body mass on the time elapsed until nest completion in the UV experiment. The larger and heavier a male, the faster he completed his nest. In the brightness control experiment there was a significant effect only of body mass on the duration of nest completion. Whether nest building preferences with respect to UV lighting conditions are context dependent needs to be tested for instance by nest-site choice experiment under increased predation risk