Mean Maximum Depth Research Articles

Macroinvertebrate Spatial Diversity Patterns of Shore Habitats in Italian High-Altitude Natural and Permanent Lakes and Ponds

A comparative analysis of environmental conditions between Alpine and Apennine lakes/ponds which represent different faces of European mountain regions was conducted. The data set was created on the basis of previous works carried out by national and international institutions including biological, physical–chemical, geographic, and precipitation data from 27 lakes/ponds placed at altitudes ranging from 2334 ± 294 m a.s.l. (in the Alps) and 1541 ± 154 m a.s.l. (in the Apennines), with mean maximum depths of about 5.5 ± 4.6 m. A specific focus was dedicated to chironomids as outstanding sentinels for local and global changes in habitat conditions. Species richness and Taxonomic Distinctness Indices were applied to lakes/ponds macroinvertebrates to highlight differences in the biodiversity of the two areas. Subsequently, associations between descriptors of the mountain region climate, lithology, water chemistry, lake morphology, geography, macroinvertebrate assemblage richness, and distinctness were examined through Principal Component Analysis, Analysis of Variance, and Non-metric Multi-dimensional Scaling. Results showed strong positive correlations between mean annual precipitation and temperature with lake macroinvertebrate biodiversity as a whole and with chironomid in particular. Thus, these shore habitats face a threat under climate change conditions (impacting thermal and precipitation regimes). These results are also central in showing that even small ecosystems are important sources of biodiversity for the lower altitudes, stressing the urgency of including them within targeted monitoring and action plans to preserve their peculiar habitat, flora, and fauna.

Clinical evaluation of needle-free electronic pneumatic hyaluronic acid injection treatment for facial atrophic acne scars: A prospective, randomized comparative trial.

Acne scars are common but difficult to treat, and an effective new treatment strategy is desired. This prospective, split-face randomized controlled trial was designed to compare the safety and efficacy of needle-free electronic pneumatic hyaluronic acid injection (EPI-HA) treatment for acne scars. Thirty Japanese subjects with moderate to severe facial atrophic acne scars underwent EPI-HA treatment on a randomized side of their face. Three treatment sessions were carried out at 1-month intervals, and the subjects were followed-up for 3 months after the final treatment. Three months after the final treatment, 48.3% of treated sides met the criteria for success, compared with 0% for the control sides (P < 0.0001). Rolling type scars were much improved compared with boxcar types and icepick types. Satisfaction (or better) was reported by 55.2% of subjects at the 3-month follow-up after the final treatment, which was similar to the physicians' assessment. Three-dimensional in vivo imaging analysis detected significant difference in scar reductions between the treated and control sides in the mean scar area, scar depth, and maximum depth of the biggest scar at 1 and 3 months after the final treatment (all P < 0.05). In conclusion, EPI-HA treatment significantly improved rolling facial atrophic acne scars in our Japanese subjects, with minimal side effects.

Vehicle Distance Estimation from a Monocular Camera for Advanced Driver Assistance Systems

The purpose of this study is to propose a framework for accurate and efficient vehicle distance estimation from a monocular camera. The proposed framework consists of a transformer-based object detector, a transformer-based depth estimator, and a distance predictor. The object detector detects various objects that are mostly symmetrical from an image captured by the monocular camera and provides the type of each object and the coordinate information of a bounding box around each object. The depth estimator generates a depth map for the image. Then, the bounding boxes are overlapped with the depth map to extract the depth features of each object, such as the mean depth, minimum depth, and maximum depth of each object. The present study then trained three models—eXtreme Gradient Boosting, Random Forest, and Long Short-Term Memory—to predict the actual distance between the object and the camera based on the type of the object, the bounding box of the object (including its coordinates and size), and the extracted depth features. The present study proposes including the trimmed mean depth of an object to predict the actual distance by excluding the background pixels around an object but within the bounding box of the object. The evaluation results show that the proposed framework outperformed existing studies.

Home ranges and diving behavior of endangered New Zealand sea lions along the Catlins coast of South Island, New Zealand

AbstractNew Zealand sea lions (NZSL, Phocarctos hookeri) were extirpated from mainland New Zealand during pre‐European subsistence hunting. They began reoccupying South Island in 1994, and the newest breeding colony arose in 2006 along the Catlins Coast on southeastern South Island and currently consists of &lt;10 individuals. The goal of this study was to use animal‐borne satellite telemeters and miniature data recorders (MDRs) to determine home ranges, three‐dimensional movements, and foraging strategy of female NZSL along the Catlins Coast during the austral winter of 2019. Total home ranges were small (97 km2) and primarily restricted to nearshore areas. Dives were shallow (8.9 m), short in duration (1.4 min), and had a mean swimming speed of 1.5 m s−1. We identified three dive types based primarily on total dive duration, mean maximum depth, total distance swam, and path linearity. The estimated at‐sea metabolic rate varied among dive types because of differences in flipper stroke frequency and swim speed. Female NZSL along the Catlins Coast have smaller home ranges and make shorter foraging trips compared with females in the Auckland Islands, and suitable habitat for breeding and prey availability along the southeast coast are encouraging for future population growth.

Paleohydraulic analysis of an ancient distributive fluvial system

ABSTRACTReconstructing the paleohydraulics of ancient fluvial systems has important implications when determining channel-body dimensions in the subsurface as well as aiding source-to-sink studies and quantitatively determining the impact of changing climatic conditions. We undertake a paleohydraulic analysis of the Upper Jurassic Salt Wash distributive fluvial system (DFS) of the Morrison Formation, SW USA, to determine if downstream trends such as decreasing channel size and discharge, inferred in studies of DFS, are present. Channel depth was estimated using cross-set height values and preserved bar thickness. Nine localities across the exposed part of the Salt Wash system were studied. In total, 49 bars were measured, full bar thickness was determined from 12 complete bars, and average cross-set height was calculated for 37 bars. Estimates of maximum bankfull channel depth were derived from measured bar thicknesses. Bar height was then obtained and converted to mean bankfull channel depth using a shape adjustment factor of 0.65. The bar-derived mean bankfull channel depths were then used to derive a factor for which dune cross-set heights could be converted to mean bankfull channel depth (4.6) and maximum bankfull channel depth (7.1). These factors were then applied to localities where only cross-set height data were available, thus allowing consistent comparison and extrapolation of mean bankfull channel depth over the preserved DFS area. The use of measured bar thicknesses to calibrate estimates of mean channel depth from reconstructed dune heights is considered a useful approach, with the factor of 4.6 estimated here being lower than that (6 to 10) commonly used in comparable studies.The datasets for the Salt Wash DFS record systematic downstream trends in cross-set height, bar thickness, calculated channel depth, estimated channel width, and estimated Q, with variability and overlap between the proximal to medial, and medial to distal parts. The variability superimposed on the regional downstream trends is attributed to a combination of autocyclic processes such as variations in discharge, depth of scour, and avulsion as well as more regional-scale channel-belt switching together with allocyclic controls. The wide spatial distribution of the dataset in this study allows distinction between local autocyclic controls and regional downstream trends. Formative discharge shows no downstream trend across the entire Salt Wash DFS, with a wide range in coefficient of variation of preserved cross set thickness (CV(dst) values of 0.1 to 1.1) indicative of flashy (variable) discharge.The spatial distribution of the Salt Wash dataset allows extrapolation of trends upstream to the unexposed part of the system that allows insights into the characteristics of the channel system in the apex area (∼ 150 km to the southwest and removed by post depositional erosion). The fluvial system would have a mean depth of 9 m, and a bankfull-depth discharge of around 1450 m3/s with mean cross-set heights of between 50 and 70 cm. These estimates are in line with those from present-day DFSs in the Himalayan and Andean foreland basins that have a scale similar to that estimated for the Salt Wash system.

Habitat associations of post-breeding female southern elephant seals (Mirounga leonina) from Península Valdés, Argentina

Research on marine mammal habitat-associations often uses satellite remote sensing of sea surface temperature, chlorophyll concentration, and sea surface height to map mesoscale features, which may indicate areas of enhanced productivity and prey availability. However, for species that feed at depths >400 m, the increased productivity associated with mesoscale features observed near the surface may have little or no immediate effect on habitat-associations at depth. As a result, previous studies have found a weak correlation between mesoscale features and the movements of marine mammals. The advantage of biologging is that hydrographic variables are recorded in situ and at foraging depths using animal-borne instruments with sensors for temperature, conductivity (salinity), and dissolved oxygen. The goal of this study was to characterize the habitat-associations of female southern elephant seals (SES) from Península Valdés, Argentina during the post-breeding foraging trip. Although female SES exhibited significant habitat-associations with sea surface height anomaly and chlorophyll concentrations, the presence or absence of eddies was not predictive of foraging behavior, and the majority of foraging dives (74%) and prey encounters (77%) occurred in the absence of eddies. The strongest habitat-association was with deep (>500 m) and cold (3.73 ± 1.29 °C) subantarctic water, primarily during foraging dives from dusk to dawn. Female SES made most of their foraging dives (68%, mean maximum depth of 539 ± 226 m) and had the most prey encounters (67%) in Antarctic Intermediate Water (AAIW), which is formed near the Subantarctic Front on the northern flank of the Antarctic Circumpolar Current. Our results suggest that AAIW is the principal foraging habitat of female SES from Península Valdés, which may not be directly associated with near-surface mesoscale features. Future research on the habitat-associations for SES and other deep-diving marine mammals should focus on indices of foraging success and the hydrographic features of water masses at foraging depths, not mesoscale features observed near the surface.

Characterization of multi-material 316L-Hastelloy X fabricated via laser powder-bed fusion

The aim of this work is to provide firsthand knowledge of 316 L stainless steel (316 L) and Hastelloy X (HX) multi-material processing via laser powder bed fusion (PBF). Specifically, microstructure of the interface is studied using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). Surface metrology is performed to characterize the resulting surface roughness at the interface followed by tensile and flexural testing of multi-material samples to characterize the mechanical properties of the interfaces. Results showed that use of proper process parameters for each individual material led to formation of a compositional gradient at the interface that stretched for 240 μm (10–12 layers) with no evidence of cracking or porosity. The interface exhibited higher surface roughness compared to 316 L or HX as measured by arithmetic mean height, Sa, and maximum valley depth, Sv, parameters. During tensile testing, samples failed in the 316 L region away from the interface, with comparable yield strength, ultimate strength, and ductility. Finally, it was concluded that the “naturally” formed interface created a compositional gradient which was defect free due to similar values of coefficient of thermal expansion, input energy density, and different Marangoni numbers of the materials.

Morphometric study of the suprascapular notch and scapular dimensions in adult Malawian cadavers and implications of completely ossified superior transverse scapular ligament.

Introductionthe anatomy of the suprascapular notch and its relationship to scapular dimensions are critical in the management of suprascapular neuropathies. Individuals show considerable differences in the dimensions of the suprascapular notch across populations. The purpose of this study was to determine the morphology and morphometric dimensions of the suprascapular notch in adult Malawian cadavers and to suggest clinical implications associated with complete ossification of the suprascapular ligament.Methodsadult dry scapulae from undetermined sex specimens (n=125) obtained from the skeletal collection at Kamuzu University of Health Sciences were classified according to the Rengachary categorization method to assess the suprascapular notch superior transverse distance, mid transverse distance, depth, scapula length and width using a standard Vernier caliper.Resultsthe most prevalent suprascapular notch class was type I, which was found in 46 (36.8%) of all scapulae. Type VI was the least common, found in only 1 (0.8%) of the scapulae. The mean notch superior transverse distance was 1.3 ± 0.6 cm, while the mean maximum depth was 0.6 ± 0.3 cm. Only the differences in depth, however, were statistically significant (p=0.001).Conclusionthe current study has described the morphology and morphometry of the suprascapular notch in relation to the risk of suprascapular nerve entrapment associated with complete ossification of the suprascapular ligament. Our sample population generally showed smaller suprascapular notch and scapular dimensions than other populations. This should be considered during the management of suprascapular neuropathy and preoperative planning of surgical operations of the shoulder region.

Influence of masticating cycles and chewing patterns on inadvertent enamel wear caused by zirconia brackets.

Little information is available about enamel wear caused by zirconia brackets, an inadvertent side effect of orthodontic treatment. The purpose of this study was to examine potential enamel damage induced by contact with zirconia brackets. Sliding and impact wear simulations were performed using bovine enamel specimens positioned at a 25° slant to a zirconium ball to determine wear behaviour. Different chewing patterns, tapping and grinding, were simulated. Specimens were profiled using confocal laser scanning microscopy, and the mean maximum depth and surface roughness were measured. Scanning electron microscopy was also performed. The mean maximum depth of wear values differed according to the number of mastication cycles, with a higher number of cycles producing higher depths of wear. The facet wear depth was significantly greater with the tapping pattern than with the grinding pattern. Scanning electron microscopic observation of the wear facets revealed that surface textures at the edges were rougher than those at the centre of all facets. The results of this study indicated that enamel wear was induced by contact with zirconia brackets during the early period of mastication, and that the patterns and number of cycles of mastication affected the wear progression of enamel.

South Atlantic Coral Reefs Are Major Global Warming Refugia and Less Susceptible to Bleaching

Mass coral bleaching has increased in intensity and frequency and has severely impacted shallow tropical reefs worldwide. Although extensive investigation has been conducted on the resistance and resilience of coral reefs in the Indo-Pacific and Caribbean, the unique reefs of the South Atlantic remain largely unassessed. Here we compiled primary and literature data for reefs from three biogeographical regions: Indo-Pacific, Caribbean and South Atlantic and performed comparative analyses to investigate whether the latter may be more resistant to bleaching. Our findings show that South Atlantic corals display critical features that make them less susceptible to mass coral bleaching: (i) deeper bathymetric distribution, as species have a mean maximum depth of occurrence of 70 m; (ii) higher tolerance to turbidity, as nearly 60% of species are found in turbid conditions; (iii) higher tolerance to nutrient enrichment, as nitrate concentration in the South Atlantic is naturally elevated; (iv) higher morphological resistance, as massive growth forms are dominant and comprise two thirds of species; and (v) more flexible symbiotic associations, as 75% of corals and 60% of symbiont phylotypes are generalists. Such features were associated with occurrence of fewer bleaching episodes with coral mortality in the South Atlantic, approximately 60% less than the Indo-Pacific and 50% less than the Caribbean. In addition, no mass coral mortality episodes associated with the three global mass bleaching events have been reported for the South Atlantic, which suffered considerably less bleaching. These results show that South Atlantic reefs display several remarkable features for withstanding thermal stress. Together with a historic experience of lower heat stress, our findings may explain why climate change impacts in this region have been less intense. Given the large extension and latitudinal distribution of South Atlantic coral reefs and communities, the region may be recognized as a major refugium and likely to resist climate change impacts more effectively than Indo-Pacific and Caribbean reefs.

The fibular notch: an anatomical study.

Reduction of the distal fibula into the fibular notch (FN) poses a problem that has not been fully resolved, yet. A number of methods have been developed for the assessment of the position of the fibula in the FN, but none of them is ideal. A majority of authors assess the FN 1cm above the tibiotalar joint space, without specifying the reason for the choice of this distance. None of the previous studies has addressed at what level the FN is the deepest. Our findings show that it is 4-5mm above the ankle joint space and verification of this hypothesis has been the aim of this study. Dry adult tibial bone specimens from the Pachner's collection of the Institute of Anatomy of 1st Faculty of Medicine, Charles University, Prague were used in the study. Height of the FN at its widest point, 3mm and 10mm above the articular surface of the distal tibia were measured in each specimen, as well as the depth of the FN at the deepest point, 3mm and 10mm above the articular surface of the distal tibia and the distance between the highest point of this surface and the deepest point of the notch. The mean length of the tibia was 350mm; the mean height of the FN was 42.5mm; the mean width of the FN at its widest point was 23.6mm, at 3mm above the tibiotalar joint space 22mm, 10mm above this articular surface of distal tibia (tibial plafond) 18.9mm. The mean depth of the notch at 3mm above the tibial plafond was 3.8mm, at 10mm above this surface 4.1mm. The maximum mean depth of the notch was 4.5mm, the distance from this point to the highest point of the tibial plafond was 5.3mm. The deepest point of the FN lies 5mm above the articular surface of the tibial plafond, with the mean value of the depth being 4.5mm. This region is, therefore, ideal for assessment of the position of the distal fibula in the FN.

Water Depth Underpins the Relative Roles and Fates of Nitrogen and Phosphorus in Lakes.

Eutrophication mitigation is an ongoing priority for aquatic ecosystems. However, the current eutrophication control strategies (phosphorus (P) and/or nitrogen (N)) are guided mainly by nutrient addition experiments in small waters without encompassing all in-lake biogeochemical processes that are associated largely with lake morphological characteristics. Here, we use a global lake data set (573 lakes) to show that the relative roles of N vs P in affecting eutrophication are underpinned by water depth. Mean depth and maximum depth relative to mixing depth were used to distinguish shallow (mixing depth > maximum depth), deep (mixing depth < mean depth), and transitional (mean depth ≤ mixing depth ≤ maximum depth) lakes in this study. TN/TP ratio (by mass) was used as an indicator of potential lake nutrient limitation, i.e., N only limitation if N/P < 9, N + P colimitation if 9 ≤ N/P < 22.6, and P only limitation if N/P ≥ 22.6. The results show that eutrophication is favored in shallow lakes, frequently (66.2%) with N limitation while P limitation predominated (94.4%) in most lakes but especially in deep ones. The importance of N limitation increases but P limitation decreases with lake trophic status while N and P colimitation occurs primarily (59.4%) in eutrophic lakes. These results demonstrate that phosphorus reduction can mitigate eutrophication in most large lakes but a dual N and P reduction may be needed in eutrophic lakes, especially in shallow ones (or bays). Our analysis helps clarify the long debate over whether N, P, or both control primary production. While these results imply that more resources be invested in nitrogen management, given the high costs of nitrogen pollution reduction, more comprehensive results from carefully designed experiments at different scales are needed to further verify this modification of the existing eutrophication mitigation paradigm.

Temporal Variations of Water Quality Parameters, Phytoplankton, And Invertebrates In Environmental Change Hotspots: A Case of Lake Wamala, Uganda

Lake Wamala (Uganda) is a small shallow lake (maximum mean depth = 4.5m) that has periodically undergonefluctuations in depth and area because of changes in rainfall, temperature and wind speed. No study, however,has been done to assess how these changes, in addition to catchment degradation, which are likely to intensify in future, have affected aquatic productivity processes. Data on Secchi depth (SD), turbidity, conductivity, dissolved oxygen (DO), total phosphorous (TP), soluble reactive phosphorus (SRP), soluble reactive silicon (SRSi), ammonia (NH4-N), nitrite nitrogen (NO2-N), nitrate nitrogen (NO3-N), Chlorophyl a, composition and abundance of algae, and invertebrates were compared between periods 1998-2000 and 2011-2013. Results showed a twofold increase in conductivity and TP, a threefold increase in SRSi, chlorophyll a &gt; 25 ?g l-1, and persistence by low water transparency (SD &lt; 0.7 m). In consequence, algal biomass increased by &gt;70%, with emergence of new species, especially among the dinoflagellate and euglenophyte groups. Although rotifers, which are known to have capacity to withstand stressful habitat conditions, dominated the zooplankton, their density decreased by &gt;80%. The phantom-midge, chaoborus, and the midge, chironomid, larvae dominated macro-invertebrate, but did not show clear trends between the two periods.

Transcatheter closure of patent foramen ovale for the secondary prevention of decompression illness in professional divers: a single-centre experience with long-term follow-up.

Patent foramen ovale (PFO) with occasional right-to-left shunting is associated with an increased risk of decompression illness (DCI). Divers with a history of repetitive or severe DCI and diagnosed with PFO should be considered for transcatheter closure if they wish to continue with unrestricted diving. To summarise our centre's experience in transcatheter PFO closure in professional divers with a history of DCI. A follow-up of 11 consecutive divers (nine males, two females) in whom device PFO closure was performed between 2001 and 2015 was carried out by phone contact. Available medical records and diving logbooks were reviewed to determine individual DCI symptomatology, indications to the procedure, and to evaluate modifications in the diving practice. Each patient experienced at least one event of DCI before the procedure, and eight patients experienced more than one event. Total number of reported events was 62. The vast majority of events (97%) followed dives consistent with safe decompression policies. The median follow-up was 91 (minimum nine, maximum 172) months. No complications of the intervention were observed. All patients returned to unrestricted, deep diving, performing a total of 3610 dives with the median number of 225 dives (lower quartile value: 82.5 dives, upper quartile value: 725 dives). The majority of subjects dived as deep as they did before the intervention, or deeper, achieving mean maximum depth of 93.8 ± 35.6 m (vs. 89.7 ± 25.9 m before the intervention, p = 0.71). No episodes of DCI were reported during the follow-up period. Transcatheter closure of PFO appears to be reasonably effective in secondary prevention of DCI associated with intra-cardiac shunting.

Bathymetric distributions of notothenioid fishes

There has been no comprehensive study of the bathymetry of notothenioid fishes. Therefore, I analyzed minimum and maximum depths and depth ranges for 128 of 142 species that collectively range from 0 to ≈3000 m. Means (and medians) for maximum depths are 176 m (75 m) for non-Antarctic, 511 m (360 m) for sub-Antarctic, and 963 m (899 m) for Antarctic species; medians are significantly different. Means (and medians) for depth ranges for the three groups are 140 (55 m), 470 (345 m), and 727 m (714 m), respectively, with significantly different medians. The mean maximum depths for the Cryonotothenioidea are: Nototheniidae—525 m, Harpagiferidae—88 m, Artedidraconidae—906 m, Bathydraconidae—1165 m, and Channichthyidae—910 m. If five species of Bathydraco, with a mean of 2098 m are excluded, the mean for the Bathydraconidae is 741 m. With the exceptions of the harpagiferids and Bathydraco, there is overlap of the 95% confidence intervals for the means of other families. Thirteen Antarctic and sub-Antarctic species with maximum depths and/or depth ranges ≥1500 m are especially deep-living: four nototheniids, four species of Bathydraco, three species of Pogonophryne, and two channichthyids. The most common depth range is 0–50 m for non-Antarctic, 200–400 m for sub-Antarctic and 600–800 m for Antarctic species. Three species have depth ranges >2000 m. Species diversity peaks at 50 m for non-Antarctic, 100 m for sub-Antarctic, and 500 m for Antarctic species. Notothenioids are not eurybathic compared with older deep-sea taxa but are eurybathic relative to marine percomorphs.

Dentinal Tubule Penetration of a Calcium Silicate–based Root Canal Sealer with Different Obturation Methods

IntroductionThe purpose of this study was to investigate the depths of penetration of a calcium silicate–based sealer in dentinal tubules by using 3 different obturation methods. MethodsOne hundred extracted human permanent anterior teeth were endodontically prepared and divided equally into 3 experimental groups and 1 control group as follows: CPoint single cone (CPSC), gutta-percha single cone (GPSC), gutta-percha vertical condensation (GPVC), all with a calcium silicate–based sealer and calcium indicator Fluo-3, and CPoint single cone with a calcium indicator Fluo-3 (CPF3) without sealer as the control. The roots of the teeth in each group were axially cross-sectioned, and the surfaces were examined under confocal laser scanning microscopy at ×10 and ×20 magnifications. The sealer penetration depths were measured at their maximum depths and at 4 circumferential depths (12, 3, 6, and 9 o'clock) by using fluorescence. ResultsStatistical analyses by using one-way analysis of variance and repeated measures analysis with linear mixed models showed no statistically significant difference among the mean maximum depth measurements (CPSC, 283.83 μm; GPSC, 318.66 μm; and GPVC, 313.03 μm; P = .7553) and among the average depths across all points (CPSC, 111.24 μm; GPSC, 135.38 μm; and GPVC, 126.62 μm; P = .5304) for the 3 experimental groups. ConclusionsThe pressure derived from hygroscopic expansion of CPoint or warm vertical condensation did not enhance penetration depths of the calcium silicate–based sealer. Sealer penetration into the dentinal tubules occurred independent of the obturation technique.

Comparison of Three Different Sealer Placement Techniques: An In vitro Confocal Laser Microscopic Study.

Introduction:Three-dimensional obturation of the root canal system is the final objective of root canal therapy. Greater penetration of sealer in root dentine lesser will be the voids at the dentine–sealer interface. Hence, analysis of the dentin/sealer interface allows the determination of a filling technique which could obturate the root canals with least gaps and voids. Therefore, the aim of this study is to compare the depth and percentage of sealer penetration into root dentin using three different root canal sealer placement techniques under confocal laser scanning microscope.Materials and Methods:Thirty single-rooted teeth were selected and prepared. Adseal sealer (Meta Biomed, South Korea) was mixed with Rhodamine B dye and applied using lentulo spiral (Dentsply Maillefer, USA) as Group 1, bidirectional spiral (EZ-Fill– EDS, USA) as Group 2, and ultrasonic endodontic tip (Sonofile– Dentsply Tulsa, USA) as Group 3. Canals were then obturated with gutta-percha. The roots were sectioned at the 3 and 6-mm levels from the apical foramen and examined under confocal laser microscope.Results:Maximum mean depth and percentage of sealer penetration were observed for Group 1 and minimum for Group 3. Furthermore, statistical significant differences among Group 1 and Group 3 were found at 6-mm level and among Group 2 and Group 3 were found at 3-mm level (P < 0.05).Conclusion:The depth and percentage of sealer penetration of sealer are influenced by the type of placement technique and by the root canal level, with penetration decreasing apically. Lentulo spiral has shown better penetration of sealer than the bidirectional file and ultrasonics.

There's plenty of light at the bottom: statistics of photon penetration depth in random media.

We propose a comprehensive statistical approach describing the penetration depth of light in random media. The presented theory exploits the concept of probability density function f(z|ρ, t) for the maximum depth reached by the photons that are eventually re-emitted from the surface of the medium at distance ρ and time t. Analytical formulas for f, for the mean maximum depth 〈zmax〉 and for the mean average depth reached by the detected photons at the surface of a diffusive slab are derived within the framework of the diffusion approximation to the radiative transfer equation, both in the time domain and the continuous wave domain. Validation of the theory by means of comparisons with Monte Carlo simulations is also presented. The results are of interest for many research fields such as biomedical optics, advanced microscopy and disordered photonics.

The diving behaviour of the Manx Shearwater Puffinus puffinus

The diving capabilities of the Procellariformes remain the least understood component of avian diving physiology. Due to their relatively small size, shearwaters may have high oxygen consumption rates during diving relative to their available oxygen stores. Dive performance in this group should be strongly limited by the trade‐off between oxygen consumption and oxygen stores, and shearwaters could be a good model group for testing predictions of dive theory. Many earlier measurements of shearwater dive behaviour relied on observations from the surface or potentially biased technology, and it is only recently that diving behaviour has been observed using electronic recorders for many of the clades within the family. The diving behaviour of Manx Shearwaters Puffinus puffinus breeding in Wales, UK, was studied on a large sample of birds using time–depth–temperature recorders deployed on chick‐rearing shearwaters in July and August over 3 years (2009–2011). Light availability apparently limited diving as dives only occurred between 04:00 and 19:00 h GMT. All individuals routinely dived deeper than traditionally assumed, to a mean maximum depth of 31 m and occasionally down to nearly 55 m. We compiled all available data for a comparison of the dive depth across shearwater species. There was a positive allometric relationship between maximum dive depth and body mass across Puffinus and Ardenna shearwater species, as expected, but only if samples of fewer than two individuals were excluded. The large intra‐specific range in maximum dive depth in our study illustrates that apparent diversity in diving performance across species must be interpreted cautiously.

Aquatic vegetation trends from 1992 to 2012 in Hamilton Harbour and Cootes Paradise, Lake Ontario

Over the past two hundred years, anthropogenic activities have resulted in the substantial decline of the once extensive wetlands in both Hamilton Harbour and Cootes Paradise. Some of the key stressors for aquatic vegetation have been infilling, sustained high water levels and level regulation in Lake Ontario, and reduced water clarity because of eutrophication and suspended sediments. Designated an Area of Concern in 1985, remediation efforts have included upgrades to the sewage treatment plants discharging into the harbour to reduce eutrophication and the 1996 construction of a fish barrier to exclude large Carp from entering Cootes Paradise to reduce turbidity. Over the past ten years, Cootes Paradise has seen a 120% increase in the areal extent of emergent vegetation, but this still represents less than 20% of the circa 1900's marsh area. Despite substantial reductions in Carp density in Cootes Paradise, submerged aquatic vegetation has been sparse and typically found at depths of less than 0.5 m, likely because of impaired light penetration. Following a significant improvement in water clarity in Hamilton Harbour between 1987 and 1997, submerged aquatic vegetation in the harbour proper expanded, achieving a mean maximum depth of 2.9 m in 2012. Species richness was considerably lower in Hamilton Harbour when compared to Cootes Paradise; however, the species composition in both these areas indicated degraded conditions throughout the time period of our assessment. Using our recent dataset, we tested relationships that had been previously established in the literature between emergent extent and water levels for Cootes Paradise and also the connection between maximum depth of submergent colonization and Secchi depths but simple univariate tests were not significant. A combination of small sample size, simple tests, and a small range for the independent variable may be issues in establishing simplified response relationships and are likely oversimplifications of vegetation response in the area that require more complex modelling.