The role of nutrients, productivity, and climate in determining tree fruit production in European forests

Fruit production (NPPf), the amount of photosynthates allocated to reproduction (%GPPf) and their controls for spatial and species-specific variability (e.g. nutrient availability, climate) have been poorly studied in forest ecosystems. We characterized fruit production and its temporal behaviour for several tree species and resolved the effects of gross primary production (GPP), climate and foliar nutrient concentrations. We used data for litterfall and foliar nutrient concentration from 126 European forests and related them to climatic data. GPP was estimated for each forest using a regression model. Mean NPPf ranged from c. 10 to 40 g C m−2 yr−1 and accounted for 0.5-3% of GPP. Forests with higher GPPs produced larger fruit crops. Foliar zinc (Zn) and phosphorus (P) concentrations were associated positively with NPPf, whereas foliar Zn and potassium (K) were negatively related to its temporal variability. Maximum NPPf and interannual variability of NPPf were higher in Fagaceae than in Pinaceae species. NPPf and %GPPf were similar amongst the studied species despite the different reproductive temporal behaviour of Fagaceae and Pinaceae species. We report that foliar concentrations of P and Zn are associated with %GPPf, NPPf and its temporal behaviour

Synthetic imagery for the automated detection of rip currents

Rip currents are a major hazard on beaches worldwide. Although it is in-situ measurements of rips can be made in the field, it is generally safer and more cost effective to employ remote sensing methods, such as coastal video imaging systems. However, there is no universal, fully-automated method capable of detecting rips in imagery. In this paper we discuss the benefits of image manipulation, such as filtering, prior to rip detection attempts. Furthermore, we present a new approach to detect rip channels that utilizes synthetic imagery. The creation of a synthetic image involves zonation of the ‘parent’ image into key areas, such as sand bars, channels, shoreline and offshore. Then, pixels in each zone are replaced with the respective dominant color trends observed in the parent image. Using synthetic imagery increased the accuracy of rip detection from 81% to 92%. Synthetics reduce ‘noise’ inherent in surfzone imagery and is another step towards an automated approach for rip current detection

Wave breaking patterns control rip current flow regimes and surfzone retention

Recent research into rip currents has revealed the existence of multiple circulation patterns, meaning that no single escape strategy is appropriate in all situations. Rip circulation is influenced by surfzone morphology, which can be inferred from wave breaking patterns in video imagery. Wave breaking often occurs over the bars adjacent to the rip channel, with little breaking over the seaward end of the rip. However, under varying wave and tide conditions, breaking can also occur at the seaward extent of rip channels. Here, we use this difference as a novel wave dissipation parameter to classify a rip channel as either ‘open’ or ‘closed’ in terms of rip-head wave breaking. A 4-day field study provided Lagrangian rip current data at a macrotidal, dissipative beach monitored by a coastal imaging system. Using this new parameter, rip channels that were identified as closed exhibited a 31% increase in current speeds and 43% increase in horizontal vorticity compared to open channels. The transition between open and closed channels occurred over a single tidal cycle, which altered surfzone retention rates. Closed channels promoted surfzone retention, with < 25% of drifters exiting the surfzone. In comparison, open channels were more conducive to exchange, with exit rates up to 91%. Analysis of the Royal National Lifeboat Institution lifeguard rip incident database showed that open rips were disproportionately represented in the occurrence of rescue events, and calculated here to be twice as dangerous as closed rips. The use of this new open/closed parameter could be used by surf lifesaving organisations, and may have implications for the cross-shore exchange of sediment and pollutants.15 page(s

High-grade atypical epithelial cells in pancreatic mucinous cysts are a more accurate predictor of malignancy than "positive" cytology

BACKGROUND: The Sendai guidelines for risk assessment of malignancy in patients with mucinous cysts lists "positive" cytology as a high-risk feature. In the current study, the authors hypothesized that a cytological threshold of high-grade atypical epithelial cells (AEC) is a more accurate predictor of malignancy. METHODS: The clinical, radiological, and cytological data of 112 patients with histologically confirmed mucinous cysts of the pancreas were reviewed. Cytology slides were blindly reviewed and cells were classified as benign, AEC, or malignant. On histology, neoplasms were grouped as benign (low-grade and moderate dysplasia) and malignant (high-grade dysplasia/carcinoma in situ and invasive carcinoma). RESULTS: There were 92 patients with an intraductal papillary mucinous neoplasm (IPMN) and 20 with a mucinous cystic neoplasm; 39 were malignant and 73 were benign (42 with low-grade dysplasia and 31 with moderate dysplasia). Only 28% (11 of 39) of the malignant cysts were cytologically malignant with a sensitivity of 29%, a specificity of 100%, and an accuracy of 75%. AEC detected 17 additional cancers (44% of all malignant cysts; 16% more than detected on the basis of "positive" cytology). By using AEC as a surgical triage threshold, the sensitivity was 72%, the specificity was 85%, and the accuracy was 80%, with similar values for small (</= 3 cm) branch duct IPMN. Nine of 73 (12%) benign cysts were identified with AEC, 4 of which had moderate dysplasia. AEC had a positive predictive value of 87% for the detection of a mucinous cyst with moderate dysplasia or worse. CONCLUSIONS: AEC are a more accurate predictor of malignancy than "positive" cytology in aspirates of pancreatic mucinous cysts, including small branch duct IPMN. AEC warrant a "suspicious" interpretation for appropriate surgical triage

Linking the HOMO-LUMO gap to torsional disorder in P3HT/PCBM blends

The electronic structure of [6,6]-phenyl C61 butyric acid methyl ester (PCBM), poly(3-hexylthiophene) (P3HT), and P3HT/PCBM blends is studied using soft X-ray emission and absorption spectroscopy and density functional theory calculations. We find that annealing reduces the HOMO-LUMO gap of P3HT and P3HT/PCBM blends, whereas annealing has little effect on the HOMO-LUMO gap of PCBM. We propose a model connecting torsional disorder in a P3HT polymer to the HOMO-LUMO gap, which suggests that annealing helps to decrease the torsional disorder in the P3HT polymers. Our model is used to predict the characteristic length scales of the flat P3TH polymer segments in P3HT and P3HT/PCBM blends before and after annealing. Our approach may prove useful in characterizing organic photovoltaic devices in situ or even in operando