Increase In Mean Size Research Articles

Habitat preferences of Phycis blennoides (Pisces: Gadiformes): environmental factors and fishing-related ontogenic deepening

Phycis blennoides is a component of the ecosystem of the Atlantic waters of northern Spain and a species of commercial interest for fisheries in this region. However, little is known about the distribution of this species. The present study analyses the relationships between different environmental and spatial variables and distribution of P. blennoides. Biological (presence-absence, abundance, biomass and total length) and environmental data were collected from a bottom trawl survey carried out off the northern coast of Spain. These data were used in 2-step generalised additive models to examine both the relative significance of physical factors in influencing P. blennoides distribution and to generate density distribution maps. Additionally, the role of fishing effort on P. blennoides body size distribution with depth was analysed. Geospatial analyses showed that changes in annual abundance did not influence physical habitat preference. Most of the variation in spatial distribution was explained by the sampling position and depth. The analyses showed that P. blennoides exhibited habitat preferences in the waters of Galicia and the Cantabrian Sea, with higher values of presence, abundance and biomass on the upper slope and on fine-grained sediment bottoms. P. blennoides biomass increased with depth, probably due to the increased mean size of individuals with depth. Modelling results suggest that the observed ontogenetic deepening appears to be mainly driven by the life history strategy of the species, but is also reinforced by fishing effort.

Assessment of Small Scale Mine Blast Toe Volume Effect on Fragmentation Size Distribution: An Application of Edge Detection Software

This study explores the critical aspect of blast toe volume in small-scale mining operations and its impact on fragmentation size distribution. The assessment is conducted to understand the relationship between blast toe volume and the resultant blast design patterns. A comprehensive analysis is carried out using production blast result from four dolomite quarries in Akoko Edo, Nigeria, focusing on various explosive engineering parameters. The research employs advanced measurement techniques and statistical methods to quantify blast toe volume and assess its influence on fragmentation size distribution. By systematically varying blast toe volumes in controlled experiments, the study aims to establish correlations between toe volume and the resulting fragmentation size. The Variance inflation factor obtained in this study revealed that the selection of parameters during toe volume simulation must be carried out with respect to stemming length and explosive weight (MIC). The result shows that the maximum instantaneous charge has a negative correlation influence on toe volume as stemming also increases. This reveals that variation in stemming length results in low explosive energy release along the blast hole column, causing toe undulation. Finally, it was also revealed that at the blast mean size (X50) increases, the toe also increases due to the poor utilization of explosive energy at the blast column.

Low-grade oncocytic tumor: a review of radiologic and clinical features.

The 2022 World Health Organization classification of renal neoplasia expanded the spectrum of oncocytic neoplasms to encompass newly established and emerging entities; one of the latter is the low-grade oncocytic tumor (LOT). This study reports the radiologic appearance and clinical behavior of LOT. In this IRB-approved, HIPPA-compliant retrospective study, our institution's pathology database was searched for low-grade oncocytic tumors or neoplasms. Patient age, gender, and comorbidities were obtained from a review of electronic medical records, and imaging characteristics of the tumors were assessed through an imaging platform. The pathology database search yielded 14 tumors in 14 patients. Four patients were excluded, as radiologic images were not available in three, and one did not fulfill diagnostic criteria after pathology re-review. The resulting cohort consisted of 10 tumors (median diameter 2.3cm, range 0.7-5.1) in 10 patients (median age 68years, range 53-91, six women). All tumors presented as a solitary, well-circumscribed, mass with solid components. All enhanced as much or almost as much as adjacent renal parenchyma; all but one enhanced heterogeneously. None had lymphadenopathy, venous invasion, or metastatic disease at presentation or at clinical follow-up (median, 22.2months, range 3.4-71.6). Among five tumors undergoing active surveillance, mean increase in size was 0.4cm/year at imaging follow-up (median 16.7months, range 8.9-25.4). LOT, a recently described pathologic entity in the kidney, can be considered in the differential diagnosis of an avidly and typically heterogeneously enhancing solid renal mass in an adult patient.

Variable self-thinning explains hydrological responses to stand replacement in even-aged forests

That streamflow from even-aged forests is a function of forest age (the Kuczera curve) is an accepted paradigm in Australian forest hydrology and less commonly in the Northern Hemisphere. However, none of a dozen stand replacement experiments in Australian obligate seeder forests have faithfully reproduced the Kuczera curve. Here we test an alternative model based on the self-thinning line, showing that both the Kuczera curve and results of subsequent stand replacement experiments can be explained by observed changes in self-thinning after disturbance.Self-thinning in even-aged forests is dictated by the rate of reduction in stocking density as mean tree size increases. Comparison of stand basal area and stocking densities in stands of Eucalyptus regnans F. Muell, regenerated after wildfires in 1851 and 1939, suggested significant differences in self-thinning lines between age cohorts. In three large catchments, a simple forest growth and water use model only reproduced observed substantial long-term reductions in streamflow after stand replacement (mean reduction from 1940 to 1982 of 233 mm year−1) when observed cohort-specific changes in the intercept of the self-thinning line (STL) were incorporated (modelled mean reduction 235 mm year−1). Use of a single STL intercept in both pre- and post-disturbance simulations did not produce the observed streamflow responses (modelled mean reduction 37 mm year−1). Averaged over six E. regnans experimental catchments in which the dominant forest was either partly or completely removed and replaced with the same species, the observed decadal maximum streamflow reduction was only 7 mm year−1, compared to 22 mm year−1 using the model with observed STL intercepts but 200 mm year−1 using the Kuczera curve. Consequently, hydrological responses to disturbance are less predictable than previously assumed, as the reasons for changes in self-thinning behaviour are not yet understood. We speculate that in this case it is related to variability in seed supply and competition with shorter-lived understorey species in the early stages of regeneration.

Facies analysis, depositional activity, and internal structure of sieve deposits on an active alluvial fan

AbstractSieve lobes typically appear in gravel‐rich and matrix‐poor alluvial fans. Despite being extensively studied, the sieve‐lobe facies has been defined largely based on qualitative field observations without quantitative sedimentological analyses. Additionally, depositional activity of sieve lobes has not been monitored over extended periods (monthly to annually) and not directly associated with specific precipitation triggers. Furthermore, the internal geometry of sieve‐lobe built alluvial fans has not yet been imaged by subsurface methods. We performed a multi‐method analysis of sieve lobes in the Julian Alps (NW Slovenia) on an alpine alluvial fan composed of carbonate gravels. We performed a detailed textural and structural sedimentological analysis of 11 recent sieve lobes differing in size and age. A three‐year aerial survey of the alluvial fan surface with a small unmanned aircraft and photogrammetric modelling was used to detect active sieve‐lobe evolution. Detected sieve‐lobe formation events and volumetric surface changes were paired with triggering precipitation events. Ground‐penetrating radar (GPR) profiling depicted the geometry of the sieve‐lobe built alluvial fan. The sieve‐lobe facies consists of over 80% poorly sorted, open‐framework gravels and less than 2% mud. Lobes exhibit downward coarsening and increase in clast mean size. These textural and structural characteristics are present in all sieve lobes regardless of their age and size. Sieve lobes form with a sub‐annual frequency, usually following 24 h rainfall events exceeding 50 mm. Over 1000 m3 of sediment was deposited during these events. The GPR profiles confirm that the studied alluvial fan is formed predominantly by stacked sieve lobes. Quantitative sedimentary analysis of sieve lobes, monitoring of their recent evolution, and depiction of their subsurface geometry—demonstrated in this study—reinforce the challenged concept that sieve lobes are one of the main building blocks of alluvial fans. This work also demonstrates that, under specific conditions, sieving may become the dominant alluvial fan‐forming process.

Continuous supercritical CO2 assisted process for the production of nano-niosomes loaded with a second-generation antibiotic for ocular therapy

Nano-niosomes were produced by a continuous supercritical CO2 assisted process. Operating at 100 bar and 40 °C, different Span® 80 to Tween® 80 wt ratios and two surfactant to cholesterol molar ratios were tested. The 90/10 Span® 80 to Tween® 80 ratio produced the right formulation to obtain spherical and stable niosomes, with a mean diameter of 145 ± 52 nm. Adding cholesterol to niosome formulations, a general slight increase in vesicles mean size was observed and also a larger tendency to their aggregation. Ofloxacin was selected as a model drug to be loaded into nano-niosomes; the largest encapsulation efficiency of 78% and a prolonged drug release up to 5 h were measured when the 90/10 Span® 80 to Tween® 80 ratio was used in the starting formulation, in which also cholesterol, at a surfactant to cholesterol molar ratio equal to 4, was added.

Neuroprotective effect of beta-D-glucan polysaccharide on hyperglycaemia-induced cerebral injury in diabetic animal model

An edible mushroom, Aricularia polytricha is used by local Nigerians in managing diabetes-related complications including infertility and diabetic neuropathy, but this age-long practice has been going on without the corresponding clinical trial and acceptable experimentation. β-D-Glucan polysaccharide is a bioactive fractionate of Auricularia polytricha, an edible mushroom with nutritional and therapeutic property. This study was intended to investigate the neuroprotective effect of β-D-Glucan polysaccharide on hyperglycaemia-induced cerebral injury in diabetic Wistar rats. Experimental animals were grouped into four: Group A served as normal control and was placed on distilled water, while groups B, C and D were induced with diabetes using 65 mg/kg bw of streptozotocin (STZ). Diabetic animals in Groups C and D were treated with 120 mg/kg bw and 200 mg/kg bw of β-D-Glucan polysaccharide respectively. Group B served as diabetic control animals. An analysis of oxidative stress markers (superoxide dismutase, catalase and melondialdehyde) was done to estimate serum levels of the markers; histopathological examination was done to determine micro-structural alteration of brain cells; cell quantification was also done to assess the degree of hypertrophy and proliferation of neurons. Statistical analysis was carried out using Analysis of Variance at p<0.05. Results showed that hyperglycaemic ambience induced a significant increase in serum level of oxidative stress markers with a concomitant increase in cell count, volume and mean size. Increase in glial cells aggregation in the cerebral cortex are indicators of cerebral damage in diabetic control animals. However, levels of oxidative stress markers were significantly downgraded following β-D-Glucan polysaccharide administration. Glial cell aggregation and inflammatory infiltrates were also decreased in diabetic models placed on β-D-Glucan polysaccharide when compared to diabetic control animals, indicating reversal in cerebral damage. The present study suggests that β-D-Glucan polysaccharide has neuroprotective effect in diabetes-induced cerebral damage in Wistar rat.

In Vitro and in Vivo Study of the Effect of Osteogenic Pulsed Electromagnetic Fields on Breast and Lung Cancer Cells.

Introduction: Although there have been significant advances in research and treatments over the past decades, cancer remains a leading cause of morbidity and mortality, mostly due to resistance to standard therapies. Pulsed electromagnetic field (PEMF), a newly emerged therapeutic strategy, has been highly regarded as less invasive and almost safe to patients, is now a clinically accepted form to treat diseases including cancer. Breast and lung cancer are the most prevalent forms of human cancers, yet reported investigations on exploring regimes including PEMF are limited. Methods: Intended to examine the anti-tumor effects of a clinically accepted osteogenic PEMF and the possibility of including PEMF in breast and lung cancer treatments, we studied the effects of 2 PEMF signals (PMF1 and PMF2) on breast and lung cancer cell growth and proliferation, as well as the possible underline mechanisms in vitro and in vivo. Results: We found that both signals caused modest but significant growth inhibition (∼5%) in MCF-7 and A549 cancer cells. Interestingly, mice xenograft tumors with A549 cells treated by PEMF were smaller in sizes than controls. However, for mice with MCF-7 tumor implants, treatment with PMF1 resulted in a slight increase (2.8%) in mean tumor size, while PMF2 treated tumors showed a 9% reduction in average size. Furthermore, PEMF increased caspase 3/7 expression levels and percentage of annexin stained cells, indicating the induction of apoptosis. It also increased G0 by 8.5%, caused changes in the expression of genes associated with cell growth suppression, DNA damage, cell cycle arrest, and apoptosis. When cancer cells or xenograft tumors treated with combined PEMF and chemotherapy drugs, PEMF showed growth inhibition effect independent of cisplatin in A549 cells, but with added effect by pemetrexed for the inhibition of MCF-7 growth. Conclusion: Together, our data suggested that clinically used osteogenic PEMF signals moderately suppressed cancer cell growth and proliferation both in vitro and in vivo.

The importance of biophysical context in understanding marine protected area outcomes for coral reef fish populations

Multiuse marine protected areas (MPAs) that utilize a mosaic of no-take and sustainable use zones are an increasingly common tool for promoting fish population recovery while minimizing socioeconomic conflict. However, significant gaps remain in our understanding of the effects of multiuse MPAs on reef-fish populations, and how protection from fishing may interact with biophysical gradients to drive ecological outcomes. Here, we examine changes in fish assemblages inside and outside of two multiuse MPAs in Raja Ampat, Indonesia, over the first four to five years after their implementation. We use linear models to assess the impact of protection status, anthropogenic pressure, and biophysical gradients on changes in four biological metrics: abundance, biomass, mean size, and size-spectra. In addition, we use multivariate analyses to assess whether fish assemblages in protected and unprotected reefs diverged after MPA establishment. We find that both fish abundance and biomass were driven equally or more by benthic characteristics than protection status and that these environmental impacts were decoupled from the effects of MPAs. Contrary to expectations, increases in abundance were more pronounced in unprotected reefs, where fish assemblages diverged from protected reefs through an increase of herbivorous parrotfishes (Subfamily Scarinae) likely driven by increased algal production on hard-bottom reef areas. However, mean size and size-spectra improved in sustainable use zones compared to unprotected reefs, demonstrating that non-exclusionary management can provide ecological benefits, especially when combined with nearby no-take areas. Increased mean size was also associated with lower human population sizes, suggesting a strong influence of fishing pressure, which is mediated by MPAs. Our findings suggest that multiuse MPAs can quickly achieve some fisheries management objectives and that these effects are likely to increase over longer timescales. However, biophysical context can have significant impacts on reef-fish assemblages that are distinct from the effects of overlying fisheries management.

Co-transport of U(VI) and bentonite colloids: Influence of colloidal gibbsite

Although various colloids co-exist in the environment, studies on the interaction between different kinds of inorganic colloids and their combined effects on radionuclide transport have scarcely been reported. In the present paper, the influence of colloidal gibbsite, a representative metal hydroxide in groundwater, on the transport of Na-bentonite colloids and their combined effects on U(VI) transport in saturated particulate granite columns were investigated. It was found that in the presence of the colloids, whether single Na-bentonite or the mixture of Na-bentonite and gibbsite, fewer pore volumes were needed for U(VI) breakthrough, indicating a colloid-facilitated U(VI) transport due to high binding affinity of uranyl for the colloids compared to granite. Meanwhile, the breakthrough curves of U(VI) were gradually flattened and the plateau of the curve for Na-bentonite was decreased as the concentration ratio of gibbsite to Na-bentonite increased from 1:10 to 1:6. Consequently, total recoveries of U(VI) and Na-bentonite decreased with more gibbsite in the mixed colloids. The inhibition effect of gibbsite colloids was ascribed to electrostatic interactions between positively charged surfaces of gibbsite colloids and negatively charged surfaces of bentonite colloids and granite granules. The electrostatic attraction between oppositely charged colloids led to an increase of mean size in the mixed suspension which declined colloid transport and the transport of colloid associated U(VI) as well. When the gibbsite-to-bentonite ratio was increased up to 1:5, the recoveries were obviously lower than those of single U(VI) and Na-bentonite transport. The results imply that positively charged materials may be further investigated as additives to decrease the loss of buffer material by groundwater erosion and the migration of radionuclide associated on bentonite colloids.

Self-thinning tree mortality models that account for vertical stand structure, species mixing and climate

Self-thinning dynamics are often considered when managing stand density in forests and are used to constrain forest growth models. However, self-thinning relationships are often quantified using only data at a conceptualised self-thinning line, even though self-thinning can begin before the stand actually reaches a self-thinning line. Also, few self-thinning relationships account for the effects of species composition in mixed-species forests, and stand structure such as relative height of species (in mixtures), and/or size or age cohorts in uneven-aged forests. Such considerations may be important given the effects of global climate change and interest in mixed-species and uneven-aged forests.The objective of this study was to develop self-thinning relationships based on changes in the tree density relative to mean tree diameter, instead of focusing only on data for state variables (e.g. tree density) at the self-thinning line. This was done while also considering how the change in tree density is influenced by site quality and stand structure (species composition and relative height).The relationships were modelled using data from temperate Australian Eucalyptus plantations (436 plots), subtropical forests in China (88 plots), and temperate forests in Switzerland (1055 plots). Zero-inflated and hurdle generalized linear models with Poisson and negative binomial distributions were fit for several species, as well as for all-species equations.The intercepts and slopes of the self-thinning lines were higher than many published studies which may have resulted from both the less restrictive equation form and data selection. The rates of self-thinning often decreased as the proportion of the object species increased, as relative height increased (species or size cohort became more dominant), and as site (quality) index increased. The effects of aridity varied between species, with self-thinning increasing with aridity index for Abies alba, Pinus sylvestris, Quercus petraea and Quercus robur, but decreasing with aridity index for Eucalyptus nitens, Fagus sylvatica and Picea abies as sites became wetter and cooler. Self-thinning model parameters were not correlated with species traits, including specific leaf area, wood basic density or crown diameter – stem diameter allometry. All-species self-thinning relationships based on all data could be adjusted using a correction factor for rarer species where there were insufficient data to develop species-specific equations.The approach and equations developed could be used in forest growth models to calculate how the tree density declines as mean tree size increases, as height changes relative to other cohorts or species, as species proportions change, and as climatic and edaphic conditions change.

Managing plantation density through initial spacing and commercial thinning: yield results from a 60-year-old red pine spacing trial experiment

We report on a 60-year-old red pine (Pinus resinosa Aiton) spacing trial experiment located in Ontario, Canada, that included the combinations between six initial spacings (from 1.2 to 3.0 m) and the presence or absence of a commercial thinning (CT) regime, as well as their impacts on quadratic mean diameter (QMD) and stand volume yield. The CT regime, initiated at age 30, targeted a residual basal area (BA) of 38 m2·ha−1after each of four entries. Without thinning, as initial spacing increased, QMD increased; gross and net volume production peaked in the 2.1–2.4 m spacings. With thinning, similar trends with spacing were evident for QMD, although piece sizes were larger and differences between spacings were lower. The immediate increase of mean tree size caused by tree selection explained most of the differences in QMD between thinned and unthinned plots. Thinning to a common target BA resulted in similar standing volume across spacings. Cumulative gross yield was similar between spacings of <2.1 m for both thinned and unthinned stands and decreased for thinned plots for wider spacings. Greater net volume production in thinned stands with the narrower spacings confirmed that mortality was captured. Lower gross and net production for wider spacings suggested that thinning resulted in underutilized growing space.

Adaptations of Coccolithophore Size to Selective Pressures During the Oligocene to Early Miocene High CO2 World

AbstractCulture experiments with coccolithophore algae—the dominant group of marine calcifying phytoplankton—imply a strong sensitivity in growth rate, degree of cellular calcification, and cell size to changes in the carbon chemistry of their growth environment. These results underpin recent studies that have explored how these physiological parameters have varied on geological time scales, in response to changing surface ocean habitats and the concentrations of carbon in the ocean‐atmosphere system. Here, we add to this work with a study of reticulofenestrid coccolith size—the dominant coccolithophore family of the Cenozoic—over the Oligocene to Early Miocene time interval. We examine sediments from contrasting latitudes and regional environmental settings, comparing sites using coherent, updated age models to distinguish globally synchronous trends in cell size from regional trends. Our results confirm several changes in coccolith size—which is strongly correlated to cell size—that are globally reproducible within the ~1 Myr age uncertainty, including a reduction in mean size by >2 μm from 30.2 to 27 and 24.5 to 23 Ma, and then increase in mean size after 20 Ma. The main difference among regions is the presence/absence of coccoliths larger than 8 μm. We evaluate which scenarios of change in carbon dioxide, temperature, and nutrient availability could have exerted selective pressure on cell size for different size classes to produce the observed size trends at each studied site. These million‐year scale adaptations of ancient coccolithophores contribute to the understanding of phytoplankton physiology in the transition to the modern “icehouse” world.

Delayed breast cancer diagnosis after repeated recall at biennial screening mammography: an observational follow-up study from the Netherlands

BackgroundDelay in detection of breast cancer may worsen tumour characteristics, with progression of tumour size and a higher risk of metastatic lymph nodes. The purpose of this study was to investigate delayed breast cancer diagnosis after repeated recall for the same mammographic abnormality at screening.MethodsThis was a retrospective study performed in two cohorts of women enrolled in a mammography screening programme in the Netherlands. All women aged 50−75 who underwent biennial screening mammography either between January 1, 1997 and December 31, 2006 (cohort 1) or between January 1, 2007 and December 31, 2016 (cohort 2) were included.ResultsThe cohorts showed no difference in proportions of women with delayed breast cancer diagnosis of at least 2 years (2.2% versus 2.8%, P = 0.29). Most delays were caused by incorrect BI-RADS classifications after recall (74.2%). An increase in mean tumour size was seen when comparing sizes at initial false-negative recall and at diagnosis of breast cancer (P < 0.001).ConclusionsThe proportion of women with a long delay in breast cancer confirmation following repeated recall at screening mammography has not decreased during 20 years of screening. These delays lead to larger tumour size at detection and may negatively influence prognosis.

Effect of secondary polymer on self‐precipitation of pH‐sensitive polymethylmethacrylate derivatives Eudragit E100 and Eudragit L100

Interpolyelectrolyte complexes or polyplexes can be seen as interesting alternatives in the purpose of active ingredients encapsulation. Working on polymethylmethacrylate derivatives with special focus on controlled oral drug delivery, the influence of charged polyelectrolytes (polyacrylic acid, polyethylenimine, and amino‐dextran) and noncharged ones (polyvinyl alcohol, dextran 40, and Pluronic F68) has been investigated on the precipitation of two pH‐sensitive Eudragit polymers, namely, L100 and E100. Moreover, the possibility of preparing polyplexes involving the two polymethylmethacrylate derivatives with different charged and noncharged secondary polyelectrolytes has been studied. The obtained dispersions have been characterized in terms of mean particle size, size distribution, zeta potential, and morphology. Direct precipitation of Eudragit L100 by medium acidification in a batch process and in the presence of polyethylenimine allowed the production of particles with a narrow size distribution. The mean size was around 200 nm. In this case, the zeta potential was found to be +45 mV at pH = 7 in 1mM aqueous NaCl solution, and the produced suspension was stable in time since no aggregation and sedimentation have been observed. A precipitation pH of 8.16 allows us to suggest the preparation of a polyplex based on Eudragit L100 and polyethylenimine. In contrary, polyvinyl alcohol has shown ability to induce an increase in particle mean size whereas other polyelectrolytes showed no significant effect. Moreover, it was observed that polyethylenimine and polyacrylic acid solutions were able to directly induce Eudragit E100 precipitation whereas amino‐dextran and noncharged polyelectrolytes showed no effect on its precipitation and on particle size distribution.

Does harvesting affect the relative growth in Patella aspera Röding, 1798?

Length–weight relationships (LWRs) provide valuable information about growth and individual fitness on the population. LWRs are commonly used in studies on life history, population dynamics, ecosystem modelling and stock assessment. A comparative study on the effect of harvesting in the relative growth of Patella aspera between Marine Protected Areas (MPAs) and exploited areas was conducted in the archipelago of Madeira (NE Atlantic Ocean). The results showed that populations from the exploited areas exhibited a negative allometric growth whilst the populations from the MPAs showed predominantly isometric and positive allometric growth. The effects of protection from MPAs on the populations of P. aspera were not only restricted to an increase in mean size but also in a more balanced growth. This study highlight the importance of MPAs in the preservation of P. aspera populations in Madeira archipelago. Hence, these results should be used to corroborate the positive effects of MPAs in safeguarding the exploited resources, especially in oceanic islands were species are more prone to over-exploitation.

Near-IR Emitting Si Nanocrystals Fabricated by Thermal Annealing of SiNx/Si3N4 Multilayers

Silicon nanocrystals in silicon nitride matrix are fabricated by thermal annealing of SiNx/Si3N4 multilayered thin films, and characterized by transmission electron microscopy, X-ray reflectivity and diffraction analysis, photoluminescence and X-ray photoelectron spectroscopy techniques. Si nanocrystals with a mean size of about 4 nm are obtained, and their properties are studied as a function of SiNx layer thickness (1.6–2 nm) and annealing temperature (900–1250 °C). The effect of coalescence of adjacent nanocrystals throughout the Si3N4 barrier layers is observed, which results in formation of distinct ellipsoidal-shaped nanocrystals. Complete intermixing of multilayered film accompanied by an increase of nanocrystal mean size for annealing temperature as high as 1250 °C is shown. Near-IR photoluminescence with the peak at around 1.3–1.4 eV is detected and associated with quantum confined excitons in Si nanocrystals: Photoluminescence maximum is red shifted upon an increase of nanocrystal mean size, while the measured decay time is of order of microsecond. The position of photoluminescence peak as compared to the one for Si nanocrystals in SiO2 matrix is discussed.

Recovery when you are on your own: Slow population responses in an isolated marine reserve.

Geographic isolation is an important yet underappreciated factor affecting marine reserve performance. Isolation, in combination with other factors, may preclude recruit subsidies, thus slowing recovery when base populations are small and causing a mismatch between performance and stakeholder expectations. Mona Island is a small, oceanic island located within a partial biogeographic barrier—44 km from the Puerto Rico shelf. We investigated if Mona Island’s no-take zone (MNTZ), the largest in the U.S. Caribbean, was successful in increasing mean size and density of a suite of snapper and grouper species 14 years after designation. The La Parguera Natural Reserve (LPNR) was chosen for evaluation of temporal trends at a fished location. Despite indications of fishing within the no-take area, a reserve effect at Mona Island was evidenced from increasing mean sizes and densities of some taxa and mean total density 36% greater relative to 2005. However, the largest predatory species remained rare at Mona, preventing meaningful analysis of population trends. In the LPNR, most commercial species (e.g., Lutjanus synagris, Lutjanus apodus, Lutjanus mahogoni) did not change significantly in biomass or abundance, but some (Ocyurus chrysurus, Lachnolaimus maximus), increased in abundance owing to strong recent recruitment. This study documents slow recovery in the MNTZ that is limited to smaller sized species, highlighting both the need for better compliance and the substantial recovery time required by commercially valuable, coral reef fishes in isolated marine reserves.

The first large-scale assessment of three-spined stickleback (Gasterosteus aculeatus) biomass and spatial distribution in the Baltic Sea

Abstract Declines in predatory fish in combination with the impact of climate change and eutrophication have caused planktivores, including three-spined stickleback (Gasterosteus aculeatus), to increase dramatically in parts of the Baltic Sea. Resulting impacts of stickleback on coastal and offshore foodwebs have been observed, highlighting the need for increased knowledge on its population characteristics. In this article, we quantify abundance, biomass, size structure, and spatial distribution of stickleback using data from the Swedish and Finnish parts of the Baltic International Acoustic Survey (BIAS) during 2001–2014. Two alternative methods for biomass estimation suggest an increase in biomass of stickleback in the Baltic Proper, stable or increasing mean size over time, and larger individuals toward the north. The highest abundance was found in the central parts of the Baltic Proper and Bothnian Sea. The proportion of stickleback biomass in the total planktivore biomass increased from 4 to 10% in the Baltic Proper and averaged 6% of the total planktivore biomass in the Bothnian Sea. In some years, however, stickleback biomass has ranged from half to almost twice that of sprat (Sprattus sprattus) in both basins. Given the recent population expansion of stickleback and its potential role in the ecosystem, we recommend that stickleback should be considered in future monitoring programmes and in fisheries and environmental management of the Baltic Sea.

Fusion boundary evolution, precipitation behaviour, and interaction with dislocations in an Fe–22Cr–15Ni steel weldment during long-term creep

A tungsten inert gas welded joint between a novel heat-resistant austenitic steel and ERNiCrCoMo-1 weld metal was investigated before and after creep in this study. The evolution of the microstructures in the base and weld metals was discussed based on the electron back-scatter diffraction (EBSD) and transmission electron microscopy (TEM) analyses. The preferred orientations of the fusion boundary after creep revealed the influence of the applied stress on creep deformation mechanism. A cooperative nucleation process of M23C6 carbides in the base metal was proposed. The finely distributed Cu-rich phase was cut off by the dislocations during creep, leading to increased mean size and reduced amount of the nano-Cu phase. A modified triple-precipitate hardening model was constructed based on TEM observations of the interactions between the particles and the dislocations in the base metal after creep at 200 MPa. The evolution of a μ phase in the weld metal involved epitaxial growth and dissolving into the matrix.