Larger Mean Diameter Research Articles

Raindrop size distributions of summer monsoon rainfall observed over Eastern India

The present study aims to quantify the raindrop size distributions (RSDs) of Indian summer monsoon (ISM) rainfall over a tropical eastern Indian station, Rourkela using five years (2018–2021) of Thies disdrometer measurements. The RSD measurements of ISM rainfall at Rourkela are segregated into active and break spells using the standardized rainfall anomalies over the study area. The RSDs characteristics of active and break spells are analyzed and their empirical relations, which are appropriate for precipitation estimation algorithms, are also reported. A significant annual and monthly variations in RSDs is noticed between the active and break spells of the ISM rainfall over the study region. The probability distribution function (PDF) RSDs parameters (rainfall rate, liquid water content, mass-weighted mean diameter, and normalized intercept parameter) demonstrated clear distinctions between active and break spells. The active spells showed higher rainfall amounts, large mass-weighted mean diameter, and smaller normalized intercept parameters over the break spells. A further segregation of active and break spells into stratiform and convective types revealed more large size drops in convective (stratiform) precipitations of active (break) spells. Occurrence of higher rainfall amounts and large size raindrops in the active spells over the break spells can be attributed to the presence of abundant moisture and convective activity in active spells. Furthermore, the radar reflectivity-rainfall rate (Z–R), shape and slope (μ–Λ), and mass-weighted mean diameter-rainfall rate (Dm-R) relations established for the active and break spells could aid in improving the precipitation estimations of over the study region.

Soil Biopores and Non-Biopores Responses to Different Tillage Treatments in Sugarcane Fields in Guangxi, China

Different types of soil macropores respond differently to various tillage practices, owing to disparities in origin, scale, morphology, and function, consequently exerting distinct effects on soil structure. This study aimed to investigate the response mechanisms of three different soil pore types (total macropores, non-biopores, and biopores) to two distinct tillage practices: smash-ridging tillage (T) and no-tillage (NT) in sugarcane fields. The parameters characterizing soil pore treatments in two and three dimensions were obtained using X-ray computed tomography scanning technology. ImageJ and MATLAB software were employed to analyze the data and separate soil macropores into biopores and non-biopores categories. The results showed that non-biopores predominated in two-dimensional cross-sectional areas in NT treatment, whereas biopores were more dominant in T treatment. Biopores in T treatment had a higher proportion of two-dimensional pores compared to NT treatment. A three-dimensional analysis indicated that total macropores had larger mean diameters (MD) and macroporosity, with more continuous tubular pores in T treatment than that in NT treatment. However, NT treatment had more numerous non-biopores with broader spatial distribution and complex morphology. Additionally, biopores in T treatment had larger MD and branching length density (LD). These vertically developed biopores, along with high macropore connectivity and under smash-ridging tillage, could improve soil water and pore conductivity. Therefore, smash-ridging tillage was more beneficial for sugarcane growth compared to no-tillage in Guangxi of China.

Fabrication and evaluating thermophysical properties of microencapsulated organic and eutectic phase change material

This study explores the synthesis and characterization of microencapsulation of organic and eutectic phase change materials with a melting point ranging from 5 to 30 ℃ for low-temperature applications. Emulsion polymerization utilizing methyl methacrylate monomer as the shell material is employed for effective encapsulation. Comprehensive characterization of microcapsules is undertaken, including chemical composition (using Fourier transform infrared (FT-IR) spectroscopy), morphology (employing scanning electronic microscopy (SEM) and metallurgical microscope), particle size distribution (measured by ImageJ software), enthalpy (evaluated through differential scanning calorimetry (DSC)) and thermal degradation (explored via thermogravimetric analysis (TGA)). The successful production of microencapsulated phase change materials (MPCM) is confirmed by their two-phase decomposition process, the presence of specific chemical bonds, and the spherical morphology of particles with an average diameter between 25.63 and 49.62 μm. However, in the case of eutectic core material, irregular microcapsules are shaped with a larger mean diameter. It has also affected the encapsulation efficiency in which around 29.43% and 30.1% efficiencies are reached for eutectic cores compared to 45.11% and 47% in organic ones. Simultaneously, thermophysical properties of MPCMs, such as density, thermal conductivity, and specific heat, are determined using the displacement method, transient line heat source, transient hot wire, and DSC. These properties are expressed through regression equations based on the determined effective factors. The derived equations enhance the capability to implement MPCMs in practical applications and numerical simulations.

Imaging the 3D microstructural changes of ice cream during meltdown.

Ice cream is a multiphase frozen dessert that often melts during distribution and upon consumption. The meltdown phenomenon is one of the concerns in the quality preservation of ice cream for consumer convenience in the frozen food industry. In this context, X-ray tomography was used to visualise and quantify 3D ice crystal and air bubble evolution during the meltdown of ice cream. Two ice cream products, namely I and II, with varying air volume fractions, were evaluated for this study. The results indicated a small mean diameter of 66.43 ± 2.07µm at 0min and decreased to 45.74 ± 3.92µm during 10min of the meltdown of ice cream II. A large mean diameter of ice crystals of 75.02 ± 3.14µm was found in ice cream I, at 0min that decreased significantly (p < 0.05) to 54.30 ± 2.63µm during 10min of the meltdown. The air bubbles were also observed to decrease in mean diameter. The 3D datasets on the ice crystals and air bubbles described in this work provide more insight into the 3D microstructural evolution during the meltdown and are useful in controlling the sensory quality attributes of ice cream desserts.

Ancient, veteran and other listed trees as nest sites for wild-living honey bee, Apis mellifera, colonies

Wild-living honey bee (Apis mellifera) colonies naturally nest in old cavity-bearing trees throughout their range, but this important nesting habitat is in global decline. Here we determine the use of ancient, veteran and other listed trees as nest sites by wild-living honey bee colonies in Britain and investigate the effect of tree size, genus and management on occupancy. Over 1,000 trees of special interest (TSIs) were surveyed in southeast England using the Ancient Tree Inventory (ATI) of the Woodland Trust, a charity that protects and promotes trees in Britain. 2% of all TSIs and 4.4% of TSIs with cavities were occupied by wild-living honey bee colonies (n = 21). Occupancy positively correlated with tree diameter, which is surprising given that the overall sample already had a large mean diameter of 1.3 m. Wild-living colonies occupied sweet chestnut (Castanea sativa) more frequently than expected (7% versus 2% overall), probably due to their large mean diameter (1.6 m) and proportion of trees with cavities (73%). Heights of occupied tree cavities (including non-ATI trees) ranged from 0 to 18.2 m with a median of 6.8 m, entrance size ranged from 2.2 to 322 cm2 with a median of 33.8 cm2 and entrance orientation was not significantly different from random.

Kraft lignins from different poplar genotypes obtained by selective acid precipitation and their use for the production of electrospun nanostructures

Kraft lignins from different poplar genotypes (Populus alba L. “PO-10-10-20” and Populus x canadensis “Ballotino”) were isolated by selective acid precipitation (pH 5 and 2.5), chemically and structurally characterized and used together with cellulose acetate (CA) for the manufacture of nanostructures by electrospinning. Generally, lignins showed a predominance of β-β´ resinols substructures (4.7–5.3 linkages per 100 aromatic units) followed by β-O-4´ (1.6–3.3 linkages per 100 aromatic units) and β-5´ phenylcoumarans (0.5–2.4 linkages per 100 aromatic units) and a high abundance of S lignin units (S/G 3.0–4.3). Moreover, lignins showed low molecular weight values (between 5.14 and 5.59 KDa) and high phenolic content (529.1 –644.5 mg GAE/g lignin). Regarding the electrospun nanostructures obtained from Kraft lignins/CA solutions, all of them presented uniform cross-linked nanofibers with a few beaded fibers according to the suitable range values of surface tension (29.18–29.71 mN/cm), electrical conductivity (131.2–158.9 μS/cm) and dynamic viscosity (0.28–0.32 Pa.s) that biopolymer solutions showed. Nevertheless, electrospun Kraft lignins/CA nanostructures with larger mean diameters were generated from lignins at pH 5, which displayed higher phenolic and β-O-4´ contents compared to lignins at pH 2.5. On the other hand, the type of poplar lignin genotype did not exert a significant influence on the mean fiber diameter.

Air-blast atomization and ignition of a kerosene spray in hot vitiated crossflow

Increasingly stringent regulations of pollutant emissions from aviation require rapid implementation of novel combustion technologies. Promising concepts based on moderate or intense low-oxygen dilution (MILD) combustion have been investigated in academia and industry. This MILD regime can be obtained from the recirculation of the hot vitiated combustion products to raise the temperature of the reactants, resulting in distributed reaction regions and lower flame temperatures. In the present work, we consider the air-blast atomization of a kerosene spray in crossflow, which enables efficient mixing between fuel and oxidizer. We investigate experimentally and numerically the effect of the spray air-to-liquid mass-flow ratio (ALR) variation on the reaction front and flame topology of a kerosene spray flame. The spray is injected transversely into a turbulent vitiated crossflow composed of the products of a lean CH4-H2 flame. The spray flame thermal power is varied between 2.5 and 5 kW, along with the atomizer ALR between 2 and 6. The experimental characterization of the reaction zone is performed using OH* chemiluminescence and OH and fuel planar laser-induced fluorescence (PLIF). The Large Eddy Simulations (LES) of the multiphase reactive flow provide good agreement with the experimental observations. Experiments and simulations show that the ALR governs mixing, resulting in different flame stabilization mechanisms and combustion regimes. Low ALR results in a relatively small jet-to-crossflow momentum ratio and a large spray Sauter mean diameter (SMD). A thick windward reaction region is formed due to inefficient shear layer mixing between the fuel spray and the crossflow. Meanwhile, the correspondingly large spray SMD leads to isolated penetration and localized combustion of fuel clusters. At high ALR, the higher penetration and the faster droplet evaporation due to the lower spray SMD result in an efficient entrainment-induced mixing between the two streams, forming more distributed reaction regions.

Li4Ti5O12 hollow macrospheres combine high tap density and excellent low-temperature performance as anode materials for Li-ion batteries

The intrinsic low electronic and ionic conductivity severely degrades the low-temperature performance of Li4Ti5O12, especially for large sizes and high trap densities, which are essential for high active material loading. In this study, oxygen vacancy-rich Li4Ti5O12 hollow macrospheres (LTO-hm) were first prepared by a novel flame melting method. The macrospheres with a comparatively large mean diameter of 40–80 μm provide a sufficiently high tap density (1.26 g cm−3), and the unique hollow structure with ∼10 μm thick of shell reduces transfer distance of Li ions in the bulk and allows for a larger specific reactive surface. Meanwhile, the introduction of oxygen vacancies in the preparation process further improves the conductivity and Li-ion diffusion coefficient of Li4Ti5O12. Hence the prepared LTO-hm delivers excellent low-temperature performance even at a high mass loading (5 g cm−2) comparing with Li4Ti5O12 synthesized by the conventional solid-state method. It exhibits a high discharge capacity of 136.5 mAh g−1 at 1C and a capacity retention of 95.39% over 500 cycles at −20 °C. The encouraging performance provides insight into the design of Li4Ti5O12 anode for high mass loading at low temperatures.

Numerical study of light scattering and propagation in soymilk: Effects of particle size distributions, concentrations, and medium sizes

Understanding light scattering and propagation in soymilk is crucial for the nondestructive evaluation of food qualities of soymilk and its products by near-infrared spectroscopy. We aim to numerically examine light scattering and propagation in soymilk samples with different solid-content properties (particle size distributions and concentrations) and medium sizes. Using the dependent scattering theory, we calculated the light-scattering properties of the samples on the sub-nanometer scale. In contrast, we calculated light propagation on the millimeter scale using the radiative transfer theory. Our numerical results show that the scattering properties of soymilk strongly depend on the solid-content properties, implying a high correlation between the solid-content and scattering properties. The sample with the largest mean diameter and broadest size distribution has the smallest reduced scattering coefficient among the samples, although it has the largest scattering coefficient. We compared the reflected fluence rates in a cylinder and semi-infinite medium. The comparative study shows the finite size effect on light propagation can be negligible at the cylinder radius of more than 2.0 cm. In that case, the light propagation model for a semi-infinite medium is a better choice to provide fast calculations in inverse analysis on the scattering properties. Our findings are essential for further developing near-infrared spectroscopy using scattered light and the physics of light scattering in dense polydisperse media.

Study on the Effect of Topical Pre-operative Nonsteroidal Anti-inflammatory Drugs in Maintaining Mydriasis during Small Incision Cataract Surgery

A prospective, randomized, double masked, single centered comparative study done in the Bangladesh Naval Ship Patenga, Chattogram, Bangladesh, from July 2021 to June 2022, to assess the clinical benefits and effectiveness of prophylactic pre-operative topical administration of NSAIDs in maintaining mydriasis during small incision cataract surgery. Thirty patients underwent small incision cataract surgery with intra ocular lens implantation were randomized to compare the efficacy of topical NSAIDs drops (Group-A) and placebo drops (Group-B) in maintaining peroperative mydriasis. Balanced salt solution containing non preservative adrenaline was used in all patients. Pupil size was measured prior to the corneal incision and after the completion of the operation. The two groups were analyzed with respect to the changes in pupillary diameter at the beginning and at the end of the operation. The change in pupil size was significantly different among the two groups at the end of the surgery. The mean vertical and horizontal diameter of the two groups were near about similar at the beginning of the surgery. Significant differences were seen after IOL implantation with the NSAIDs group having the larger mean diameter in both vertical (P=0.003) and horizontal (P=0.008) pupillary measurements at the conclusion of surgery. Topical NSAIDs has been shown to be a more effective inhibitor of meiosis during per operative uncomplicated small incision cataract surgery and provides a more stable mydriatic effect during surgery compared to the placebo group.&#x0D; CBMJ 2023 January: Vol. 12 No. 01 P: 22-26

Contrast-Enhanced Ultrasound in Distinguishing between Malignant and Benign Peripheral Pulmonary Consolidations: The Debated Utility of the Contrast Enhancement Arrival Time

Background. Limited studies and observations conducted on a too small number of patients prevent determining the actual clinical utility of pulmonary contrast-enhanced ultrasound (CEUS). The aim of the present study was to examine the efficacy of contrast enhancement (CE) arrival time (AT) and other dynamic CEUS findings for differentiating between malignant and benign peripheral lung lesions. Methods. 317 inpatients and outpatients (215 men, 102 women; mean age: 52 years) with peripheral pulmonary lesions were included in the study and underwent pulmonary CEUS. Patients were examined in a sitting position after receiving an intravenous injection of 4.8 mL of sulfur hexafluoride microbubbles stabilized by a phospholipid shell as ultrasound contrast agent (SonoVue-Bracco; Milan, Italy). Each lesion was observed for at least 5 min in real-time and the following temporal characteristics of enhancement were detected: the arrival time (AT) of microbubbles in the target lesion; the enhancement pattern; the wash-out time (WOT) of microbubbles. Results were then compared in light of the definitive diagnosis of community acquired pneumonia (CAP) or malignancies, which was not known at the time of CEUS examination. All malignant cases were diagnosed by histological results, while pneumonia was diagnosed on the basis of clinical and radiological follow-up, laboratory findings and, in some cases, histology. Results. CE AT has not been shown to differ between benign and malignant peripheral pulmonary lesions. The overall diagnostic accuracy and sensibility of a CE AT cut-off value < 10 s in discriminating benign lesions were low (diagnostic accuracy: 47.6%; sensibility: 5.3%). Poor results were also obtained in the sub-analysis of small (mean diameter < 3 cm) and large (mean diameter > 3 cm) lesions. No differences were recorded in the type of CE pattern showed between benign and malignant peripheral pulmonary lesions. In benign lesions we observed a higher frequency of delayed CE wash-out time (WOT) > 300 s. Anyhow, a CE WOT cut-off value > 300 s showed low diagnostic accuracy (53.6%) and sensibility (16.5%) in discriminating between pneumonias and malignancies. Similar results were also obtained in the sub-analysis by lesion size. Squamous cell carcinomas showed a more delayed CE AT compared to other histopathology subtypes. However, such a difference was statistically significant with undifferentiated lung carcinomas. Conclusions. Due to an overlap of CEUS timings and patterns, dynamic CEUS parameters cannot effectively differentiate between benign and malignant peripheral pulmonary lesions. Chest CT remains the gold standard for lesion characterization and the eventual identification of other pneumonic non-subpleural localizations. Furthermore, in the case of malignancy, a chest CT is always needed for staging purposes.

Changes in Artery Diameters and Fetal Growth in Cases of Isolated Single Umbilical Artery.

Background-There are conflicting data in the international literature on the risks of abnormal fetal growth in fetuses presenting an isolated single umbilical artery (SUA), and the pathophysiology of this complication is poorly understood. Objective-To evaluate if changes in diameter of the remaining umbilical artery in fetuses presenting an isolated SUA are associated with different fetal growth patterns. Study design-This was a two-center prospective longitudinal observational study including 164 fetuses diagnosed with a SUA at the 20-22-week detailed ultrasound examination and 200 control fetuses with a three-vessel cord. In all cases, the diameters of the cord vessels were measured in a transverse view of the central portion of the umbilical cord, and the number of cord vessels was confirmed at delivery. Logistic regression and nonparametric receiver operating characteristic (ROC) analysis were carried out to evaluate the association of the umbilical artery diameter in a single artery with small for-gestational age (SGA) and with fetal growth restriction (FGR). The impact of artery dimension was adjusted for maternal BMI, parity, ethnicity, side of the remaining umbilical artery and umbilical resistance index (RI) in the regression model. Results-A significantly (p < 0.001) larger mean diameter was found for the remaining artery in fetuses with SUA compared with controls (3.0 ± 0.9 vs. 2.5 ± 0.6 mm). After controlling for BMI and parity, we found no difference in umbilical resistance and side of the remaining umbilical artery between the SUA and control groups. A remaining umbilical artery diameter of >3.1 mm was found to be associated with a lower risk of FGR, but this association failed to be statistical significant (OR = 0.60, 95% CI = 0.33-1.09, p value = 0.089). We also found that the mean vein-to-artery area ratio was significantly (p < 0.001) increased in the SUA group as compared with the controls (2.4 ± 1.8 vs. 1.8 ± 0.9; mean difference = 0.6; Cohen's d = 0.46). Conclusion-In most fetuses with isolate SUA, the remaining artery diameter at 20-22 weeks is significantly larger than in controls. When there are no changes in the diameter and, in particular, if it remains <3.1 mm, the risk of abnormal fetal growth is higher, and measurements of the diameter of the remaining artery could be used to identify fetuses at risk of FGR later in pregnancy.

Forest management plans as data source for the assessment of the conservation status of European Union habitat types

Natura 2000 is a European network of protected sites that should enable natural habitats to be maintained or restored at a favorable conservation status. Progress toward this objective must be periodically reported by states members of the European Union. We investigated how forest management plans might provide data to support the reporting. The study was done in the forests of the Dolomites and Venetian Prealps, Italy. Here, about 200 forest management plans, divided into several forest compartments, have been drawn up and revised every 10–15 years. Stand structure variables were retrieved from past (OR, 1970–1980) and more recent revisions (NR, 2000–2010) of 331 forest compartments ranging between 0.35 and 53.1 ha. In the beech and spruce forest habitat types (coded 9130 and 9410 in Annex I of the Directive 92/43/EEC, respectively), we found an increase from OR to NR in the density of large trees (from 32 to 46/ha and from 31 to 50/ha, respectively for the two habitats), basal area (from 27.3 to 31.5 m2/ha and from 31 to 34.5 m2/ha), mean diameter (from 34.1 to 36.2 cm and from 33.9 to 36 cm) and Gini index (from 0.35 to 0.37 and from 0.33 to 0.36). Pursuant to the Directive 92/43/EEC, the conservation status of these two habitat types should be taken as “favorable” with regards to the criterion related to the habitats’ specific structure and functions that are necessary for its long-term maintenance. We conclude that forest management plans provide a great portion of the information needed for assessing and monitoring the conservation status of forest habitat types in the Natura 2000 framework.

The Morphological Characteristics of Authigenic Pyrite Formed in Marine Sediments

Pyrites are widely distributed in marine sediments, the morphology of which is applied as a proxy to infer the redox conditions of bottom water, and identify diagenetic stages and hydrocarbon leakage activities. In this review, the methods used for the morphological study of pyrite are summarized. The textural and size characteristics of euhedral pyrite and pyrite aggregates, as the formation and evolution mechanism of pyrite are discussed for their significance in reconstructing the geochemical environment. The morphological study of pyrite includes shape observation, size estimation, and surface feature analysis. Scanning electron microscope and optical microscope are the main methods for morphological observation; transmission electron microscope and scanning tunneling microscope are applicable to observe nanoscale morphological structures and crystal growth on the crystal surface, and X-ray computed tomography is capable of measuring pyrite size distribution at the scale of a micrometer. Under the marine sedimentary condition, the single crystal of pyrite appears in cube, octahedron, dodecahedron, and their intermediates, the size of which ranges from several nanometers to more than 100 µm. The morphology of euhedral pyrite is controlled by temperature, pH, the chemical composition of interstitial water, etc., and might have been experienced in later reformation processes. The pyrite aggregates occur as framboid, rod-like, fossil-infilling, etc., characterized by the comparatively large size of several microns to several millimeters. It is found that certain textures correspond with different formation mechanisms and geochemical environments. Particularly, under special geological conditions, for instance, the methane leakage and/or decomposition of gas hydrate, pyrite is anomaly enriched with morphological textures of massive framboid cluster, rod-like aggregates, etc., and framboid is found with a large mean diameter (&gt;20 µm) and standard deviation (&gt;10 µm). These typical features can be employed to ascertain the position of the paleo sulfate methane transition zone (SMTZ).

Natural Regeneration Dynamics of Longleaf Pine Under Frequent, Low-Intensity Prescribed Fires in Southern Alabama, USA

Abstract Frequent (≤3 y) prescribed burn has been conducted in the Escambia Experimental Forest in southern Alabama, USA, since 2001.The change in the density of new germinants (≤1 y) and older seedlings and saplings (&amp;gt;1 y) of longleaf pine (Pinus palustris Mill.) from stands of varying conditions was quantified using the locally estimated scatterplot smoothing and spatial statistical methods. A relatively longer fire interval or time since last fire (TSLF) &amp;gt; 600 days favored the recruitment of young seedlings. However, a short fire return interval or TSLF≤ 600 days promoted the recruitment of older seedlings and saplings. Large basal area (BA) and site index (SI) tended to diminish natural regeneration, whereas large quadratic mean diameter (QMD) and age were facilitative. The interactive effect of these factors indicated that a ratio of TSLF/BA of 60 to 120 and QMD/SI of 1.8 to 2.2 would maximize the recruitment of young seedlings. The recruitment of older seedlings and saplings increased linearly with QMD/SI but had no relationship with TSLF/BA. Recruitment was largely absent when QMD/SI was &amp;lt;2.0. As a result, we recommend that QMD/SI be no greater than 2.0 and TSLF/BA range from 60 to 120 to regenerate longleaf pine naturally.

Raindrop size distribution characteristics in summer of a nival glacial zone in eastern Tianshan, Central Asia

Precipitation is a key component of the hydrological cycle, which is critical to understanding its formation and evolution. In this study, based on the observation data of the PWS100 located at the meteorological observation site at the terminal of Urumqi Glacier No. 1, eastern Tianshan Mountains, the statistical characteristics of the summer raindrop size distribution (DSD) were analyzed, and the DSD characteristics of five different rainfall rates(R) and two rainfall types (convective and stratiform) were investigated for the daytime and nighttime. The average raindrop spectral width was the largest in class III (1 &amp;lt; R &amp;lt; 5 mm h−1). The result showed that the raindrop concentration increased with the rainfall rate. The maximum raindrop concentration was at class IV (5 &amp;lt; R &amp;lt; 10 mm h−1), when the raindrop diameter was higher than 1.74 mm. The small and medium size raindrops played a dominant role in precipitation composition in the head watershed of the Urumqi River, contributing 98% of the total raindrop. The convective precipitation at the headwaters was divided into continental clusters. The stratiform/convective Dm-log10Nw was characterized by a large mass-weighted mean diameter Dm = 1.523/2.608, and a generalized intercept log10Nw = 2.841/3.469. N(D) of convective precipitation was significantly different between the daytime and nighttime, while that of stratiform precipitation was almost the same. The constraint relationship between R-Dm and R-log10Nw of these two precipitation types was deduced, the exponent of the R-log10Nw relationship of the two precipitation types was negative, and the Dm value of stratiform precipitation tended to be stable at a higher rainfall rate (1–2 mm). Finally, we deduced the power-law relationship between radar reflectivity (Z) and rain rate (R) [Z = A*Rb] for stratiform and convective precipitation at the headwaters. Z = 698.8R2.0 was for stratiform, and Z = 47.1R2.0 was for convective. These results, for the first time, offer insights into the microphysical nature of precipitation in the head watershed of the Urumqi River during the summer and provide essential information that could be useful for precipitation retrievals based on weather radar observations.

Assessment of Mandibular Anterior Nutrient Canals in Patients with and without Periodontal Disease

Background: Nutrient canals (NCs) are radiolucencies in the bone that transit blood vessels and nerves. Aim: To use cone beam computed tomography (CBCT) to assess the incidence, diameter, and location of NC in healthy and periodontal disease patients and correlate it with the extent of alveolar bone loss. Materials and Methodology: About 200 CBCTs (100 healthy and 100 with periodontal disease) were selected and analyzed. The prevalence, diameter, and location of the NCs were comparatively evaluated between the two groups. The frequency and diameter of the canals were also correlated with the severity of bone loss, age, and gender. Results: Subjects in group II had a significantly greater frequency of NCs (P = 0.0001). NCs in group II had a larger mean diameter. The NCs were nearer to the alveolar crest in group II (16.70 ± 6.31 mm) than in group I (18.08 ± 5.72 mm). Their frequency was significantly greater when the bone loss was greater than two-thirds of the root length (P = 0.043). Conclusion: In patients with periodontal diseases, the incidence and diameter of NCs were higher and correlated positively with the extent of bone loss.

Long-term effects of prescribed fire on large tree growth in mixed conifer forests at Lassen Volcanic National Park, California

Prescribed fire in dry coniferous forests of the western U.S. is used to reduce fire hazards. How large, old trees respond to these treatments is an important management consideration. Growth is a key indicator of residual tree condition, which can be predictive of mortality and response to future disturbance. Using a combination of long-term plot records and dendrochronological samples, we analyzed the effects of prescribed fire treatments from the early 1990 s on forest structure and individual tree growth in mixed-conifer forests of Lassen Volcanic National Park in northern California. Prescribed fire reduced stand live tree basal area and stem density at our sites up to 10 years following fire. Within two prescribed fire burn units and two adjacent unburned stands, we analyzed tree cores from 136 large (mean stem diameter > 70 cm) yellow pine (Pinus jeffreyi and P. ponderosa) and 136 large (mean stem diameter > 50 cm) white fir (Abies concolor). After accounting for annual precipitation, basal area increment for individual trees initially declined up to < 3 years post-fire for white fir and > 10 years post-fire for yellow pine, presumably in response to tree injuries. Growth improved for both species at a site that was burned twice, particularly for white fir. Recent average basal area increment was positively related to crown ratio and negatively associated with an index of local competition. Our findings suggest that forest management, such as prescribed fire and mechanical thinning, may be beneficial in terms of maintaining or improving tree growth among large residual trees. However, managers may want to balance the benefits of these treatments against inadvertent injury and mortality of large trees.

Multi-Case Analysis of Ice Particle Properties of Stratiform Clouds Using In Situ Aircraft Observations in Hebei, China

This study investigates the size distribution, the mean diameter, and the concentration of ice particles within stratiform clouds by using in situ observations from 29 flights in Hebei, China. Furthermore, it examines the empirical fitting of ice particle size distributions at different temperatures using Gamma and exponential functions. Without considering the first three bins of ice particles, the mean diameter of ice particles (size range 100–1550 µm) is found to increase with temperature from −15 to −9 °C but decrease with temperature from −9 to 0 °C. By considering the first three bins of ice particles using the empirical Gamma fitting relationship found in this study, the mean diameter of ice particles (size range 25–1550 µm) shows a similar variation trend with temperature, while the turning point changes from −9 to −10 °C. The ice particle number concentration increases from 13.37 to 50.23 L−1 with an average of 31.27 L−1 when temperature decreases from 0 to −9 °C. Differently, the ice concentration decreases from 50.23 to about 22.4 L−1 when temperature decreases from −9 to −12 °C. The largest mean diameter of ice particles at temperatures around −9 and −10 °C is most likely associated with the maximum difference of ice and water supersaturation at that temperature, making the ice particles grow the fastest. These findings provide valuable information for future physical parameterization development of ice crystals within stratiform clouds.

Relationship between actinic keratosis and malignant skin lesions on the eyelid.

To evaluate the variables possibly related to actinic keratosis and malignant skin lesions on the eyelid. A prospective study of patients with suspected eyelid malignancy was conducted. The participants underwent a 2-mm punch biopsy at two opposite sites of the lesion for diagnosis, and the results were compared with those of the histopathological study of the surgical excised specimen. The patients with an actinic keratosis component were divided into two groups (actinic keratosis-associated malignancy and actinic keratosis alone), which were compared for the following variables: age, disease duration, largest diameter, tumor area, Fitzpatrick classification, sex, tumor site and margin involvement. A cluster analysis was also performed. We analyzed 174 lesions, of which 50 had an actinic keratosis component. Actinic keratosis was associated with squamous cell carcinoma in 22% of the cases and to basal cell carcinoma in 38%, which shows that both neoplasms may have contiguous actinic keratosis. Statistical analysis revealed no significant difference among the variables. In a cluster analysis, four groups were identified with malignant lesions in the medial canthus with the largest mean diameter and area. All margin involvements on the lower eyelid were related to malignancy, which means that all cases with margin involvement had an almost 100% risk of malignancy. Larger actinic keratosis lesions in the medial canthus and lesions with margin involvement on the lower eyelid have a greater probability of malignant association.