Circular Sample Research Articles

Pronounced effect of lamination on plasma separation from whole blood by microfluidic paper-based analytical devices

Many diseases are detected through blood tests. Currently, most blood tests are done on plasma instead of whole blood because of the interference of blood cells on detection results. Here, we developed a laminated microfluidic paper-based analytical device (L-μPAD) for the separation of plasma from whole blood without using plasma separation membrane (PSM). A lateral flow design consisting of a circular sampling zone and rectangular detection zone was patterned on the paper substrate using laser printing technology. The μPAD was then laminated after impregnation with KCl solution. Lamination and electrolyte addition represented synergistic effects on the separation by controlling the pore size of the paper. In addition, by preventing evaporation on one hand and squeezing paper pores on the other hand, lamination caused longer movement of the separated plasma, the longest plasma path reported so far. The separation process was monitored using colorimetric reagent bromocresol green and scanning electron microscopy. The process of separation was completed in less than 90s without significant hemolysis and the separated plasma was far from the interfering effect of red blood cells. We used the device for the determination of serum albumin. However, it represents the potential for point-of-care testing in multi-assay experiments too.

Effect of aggregate characteristics on properties of cemented sand and gravel

Abstract To improve the stability of cemented sand and gravel (CSG) dam construction materials, artificial aggregates can be selected to replace missing natural aggregates, and aggregate grading optimization can be carried out to meet the needs of engineering applications. This article uses finite-element analysis software to explore the influence of aggregate characteristics on the performance and destruction characteristics of CSG materials through numerical simulation. The results show that (1) with the increase of circular natural sand gravel aggregates, the peak stress and elastic modulus of the sample increase, while the strength also increases. (2) Compared to circular aggregates, polygonal aggregates have more edges and corners, which exacerbate the deformation disharmony between mortar and aggregates; the phenomenon of stress concentration is more obvious, so under the same loading step, the degree of damage of polygonal aggregates is greater than that of circular aggregates. (3) After the freeze–thaw cycle test, the deterioration of parameters in the CSG resulted in more severe damage and strength loss of the crushed stone aggregate than the circular aggregate sample. This conclusion can provide a reference for the design of CSG mix ratio in engineering sites.

Effect of Hybrid FRP Confinement on Tin Slag Polymer Concrete Compressive Strength

This study investigates the strength enhancement of Tin Slag Polymer Concrete (TSPC) under hybrid GFRP and CFRP confinement in comparison with mono GFRP and CFRP confinement on TSPC circular short column samples. Hybrid FRP confinement is prepared by wrapping TSPC with GFRP followed by CFRP both 1 layer using epoxy Sikadur 330 as matrix binders with 50 mm overlap. Compression test was performed on unconfined TSPC (TSPC-UC), TSPC with GFRP confinement (TSPC-GF), TSPC with CFRP confinement (TSPC-CF) and TSPC with hybrid FRP confinement (TSPC-HB) with 1mm/ min loading rate. The test results have revealed that the ultimate strengths are 59.19 MPa (TSPC-UC), 85.54 MPa (TSPC-GF), 108.77 MPa (TSPC-CF) and 124.59 MPa (TSPC-HB). The corresponding compressive strain measured at ultimate compressive strength is 0.0300 (TSPC-UC), 0.0453 (TSPC-GF), 0.0398 (TSPC-CF) and 0.0588 (TSPC-HB). Stress versus strain curve has shown that compared to TSPC-UC, externally strengthen sample with GFRP, CFRP and Hybrid FRP have enhanced TSPC strength with slight different behavior. TSPC-GF has less strength enhancement with larger strain while TSPC-CF provide larger strength enhancement but with lower strain. However, TSPC-HB has shown the highest strength enhancement with larger strain benefit from combined GFRP and CFRP properties. Failure mode of hybrid FRP confinement on TSPC (TSPC-HB) has shown combination of both FRP components failure mode (TSPC-GF and TSPC-CF) as in rupture pattern and delamination. The results of this study has provide findings on the effect of hybrid FRP confinement on TSPC circular column sample in close expectation based on literatures.

A Cost-Effective Method for Automatically Measuring Mechanical Parts Using Monocular Machine Vision.

Automatic measurements via image processing can accelerate measurements and provide comprehensive evaluations of mechanical parts. This paper presents a comprehensive approach to automating evaluations of planar dimensions in mechanical parts, providing significant advancements in terms of cost-effectiveness, accuracy, and repeatability. The methodology employed in this study utilizes a configuration comprising commonly available products in the industrial computer vision market, therefore enabling precise determinations of external contour specifications for mechanical components. Furthermore, it presents a functional prototype for making planar measurements by incorporating an improved subpixel edge-detection method, thus ensuring precise image-based measurements. The article highlights key concepts, describes the measurement procedures, and provides comparisons and traceability tests as a proof of concept for the system. The results show that this vision system did achieve suitable precision, with a mean error of 0.008 mm and a standard deviation of 0.0063 mm, when measuring gauge blocks of varying lengths at different heights. Moreover, when evaluating a circular sample, the system resulted in a maximum deviation of 0.013 mm, compared to an alternative calibrated measurement machine. In conclusion, the prototype validates the methods for planar dimension evaluations, highlighting the potential for enhancing manual measurements, while also maintaining accessibility. The presented system expands the possibilities of machine vision in manufacturing, especially in cases where the cost or agility of current systems is limited.

Modeling and Mapping of Aboveground Biomass and Carbon Stock Using Sentinel-2 Imagery in Chure Region, Nepal

The concerns about climate change in recent decades have heightened the need for effective methods for assessing and reporting forest biomass and Carbon Stocks (CS) at local, national, continental, and global scales. Accurate assessment of Aboveground Biomass (AGB) is critical for the sustainable management of forests, especially in the Chure region, a fragile and young mountainous in the lesser Himalaya of Nepal. This paper presents the modeling and mapping approach and shows how medium-resolution Sentinel-2 multispectral instrument (MSI) data can be used instead of hyperspectral data in inaccessible areas of the Chure region. The data were collected and analyzed from 72 circular sample plots. 60% (43 random sample plots) were used to create the model, while the remaining 40% (29 plots) were used for model validation. This study involved calculating 12 different vegetation indices and correlating them with plot-level AGB. Five models, including linear, logarithmic, quadratic, power, and exponential, were created, but the best model was found to be the quadratic model using normalized difference vegetation indices (NDVIs) with an R2 value of 0.777 and a correlation coefficient of 0.881. The model’s AIC and BIC values were 313.60 and 320.65, respectively. The validity of the model was performed using observed and predicted AGB values, resulting in an r value of 0.9128, an R2 value of 0.8332, and an RMSE value of 10.7657 t·h−1. Finally, the developed regression equation was used to map AGB in the study area. The AGB per pixel ranges from 0 to 129.18 t·h−1, whereas the amount of CS ranges from 0 to 61.01 t·h−1. Among the different vegetation indices used in the study, NDVI was found to be more precise in estimating and mapping biomass and carbon stocks in this study. Therefore, the study recommends using the quadratic model of NDVI for accurate estimation of AGB and CS in the Chure region of Sainamaina municipality.

Comparative study of forest biomass and carbon stocks of Margalla Hills National Park, Pakistan

Forests can play an important role in climate change mitigation. However, limited information is available worldwide regarding forest carbon and biomass stocks. Financial mechanisms such as ‘reducing emissions from deforestation and forest degradation and the role of conservation of forest carbon, sustainable management of forests and enhancement of forest carbon stocks’ (REDD+) also emphasize the quantification of forest biomass and carbon. This study aimed to estimate the forest biomass in two forests of Margalla Hills National Park (MHNP): Sub-tropical Chir Pine Forest (SCPF) and Sub-tropical Broadleaved Evergreen Forest (SBEF). For this, circular sampling plots of a 20 m radius were used for the collection of the variables, “diameter at breast height (DBH) and height”. Statistical analysis was done for exploring regression relationships between the variables. We found a mean Aboveground Carbon (AGC) of 73.36 ± 32.55 Mg C ha−1 in SCPF and a mean AGC of 16.88 ± 25.81 Mg C ha−1 in SBEF. The mean Aboveground Biomass (AGB) for SCPF was recorded as 146.73 ± 65.11 Mg ha−1, while for SBEF it was 33.77 ± 51.63 Mg ha−1. It was therefore concluded that the SCPF had higher mean AGB and mean AGC than the SBEF. Similar differences were also noticed in the structural characteristics of the two forests. These could be valuable information while designing sustainable management plans and afforestation programmes for the future and also for accessing nature-based funding such as REDD+.

Triple Robustness Augmentation Local Features for multi-source image registration

With the proliferation of a wide variety of sensors, accurate multi-source image registration is crucial for many remote sensing image processing tasks. However, the registration of multi-source images faces the challenges of rotations, scales, and domain transformations caused by significant differences in shooting time, viewing angle, and sensor imaging modes. To cope with this problem, we propose a deep learning-based registration method named TRFeat, which aims to comprehensively improve the rotation, scale, and cross-domain robustness of local features. First, we introduce a special circular sampling convolutional layer to replace the standard square convolutional layer, in order to enhance the rotational robustness of local features. Second, we design a scale pyramid backbone network architecture to improve the robustness of the network to scale transformations. Third, we promote the use of hypercolumn domain alignment loss to extract cross-domain robust local descriptors for images from different sources. In addition, we develop a novel keypoint detection training framework based on iterative refinement supervision to obtain repeatable and reliable keypoints localization in multi-source images. Finally, we conduct thorough experiments on five multi-source datasets. Extensive experimental results validate that our TRFeat outperforms other state-of-the-art hand-crafted (e.g. RIFT) and deep learning-based methods (e.g. ASLFeat). Specifically, our TRFeat achieves an MMA@3 of 76.08% on the HPatches dataset and an RMSE of 3.38 on the Xiang dataset. The code is available at https://github.com/vignywang/TRFeat.

Management of Acacia Plantations for Charcoal Production: Local Economies and Sustainability

The objectives of this research were to estimate volume ofcharcoal produced per unit area of Acacia seyal plantations atWadelbashier Forest Reserve and to estimate financial profitability(US$ ha-1 ) of charcoal production, using net present value (NPV) as adecision criterion. Data on tree growth was collected, using fixed-radiustemporary circular sample plots. Present and harvest age standing woodvolumes were estimated. Market-related data were collected throughstructured interviews of key informants of the staff of Forest NationalCorporation (FNC) of Algadarif State, members of Trade Union ofFuelwood Producers and Traders, and from secondary sources of thestate forestry service. The results indicated that the present standingwood volume (m3 ha-1 ) ranged between 8.4 and 26.2 and that charcoalproduction from A. seyal plantations managed for a rotation of 20 yearsat 12% annual discount rate yielded a negative mean financial NPV ofUS$ ha-1 -30.3 indicating that charcoal production at current stocking,factor costs, output prices, a 12% annual discount rate and a rotationlength of 20 years is not financially profitable. The study concludes thatpolicy and management interventions are inevitable for sustainableproduction.

Additive modeling systems to simultaneously predict aboveground biomass and carbon for Litsea glutinosa of agroforestry model in tropical highlands

Aim of study: To develop and cross-validate simultaneous modeling systems for estimating components and total tree aboveground biomass and carbon of Litsea glutinosa in an agroforestry model with cassava.
 Area of study: In the Central Highlands of Vietnam, the agroforestry model widely planted on fallow land of ethnic minorities is a mixture of 65% L. glutinosa in combination with 35% cassava (Manihot esculenta).
 Material and methods: Twenty-two 300-m2 circular sample plots were located, representing the range of tree age, plantation density, and a 6-7 year rotation cycle. In each sample plot, one selected tree with a diameter at breast height equal to the plot quadratic mean diameter was destructively sampled. The relationships among tree aboveground biomass and carbon (AGB/AGC) and their components with dendrometric variables diameter, height, age, and crown area were examined using factor analysis. To fit systems of equations for AGB/AGC and their components, we compared two methods: weighted nonlinear least-squares (WNLS) and weighted nonlinear seemingly unrelated regression (WNSUR).
 Main results: The results of the leave-one-out cross-validation showed that the simultaneous WNSUR approach to modeling systems of four tree components, total biomass, and carbon provided better results than independent WNLS models.
 Research highlights: The simultaneous WNSUR modeling system provided improved and reliable estimates of tree components, total biomass, and carbon for L. glutinosa in an agroforestry model with cassava compared to independently fitted WNLS models.

Carbon stock of Agoro Agu Central Forest reserve, in Lamwo district, Northern Uganda

Terrestrial ecosystems such as forest landscapes provide critical ecosystem services such as carbon sequestration, fundamental to people, society and the global climate change discourse. Just like moist forest, dry Afromontane forests too present a high carbon sequestration potential. However, Uganda has since not undertaken carbon stock inventories for these conservation areas, especially with dry Afromontane forests like Agoro-agu central forest reserve (CFR). So, their potential to capture and store carbon is yet to be understood in Uganda. This study was carried out to estimate carbon stock of Agoro-agu CFR, for its potential in climate change mitigation. A stratified sampling design was used, where 65 sample plots were established. Nested, fixed area circular sample plots with sub-plots of varying radii for tree height, diameter measurements and soil sampling, were used. The mean total carbon stock of Agoro-agu CFR was estimated at 606.7 Mg C ha−1, for which 409, 72, 124 and 0.24 Mg C ha−1 was stored as above ground carbon, below ground carbon, soil organic carbon and carbon in litter herbs and grass respectively. The study illustrates the carbon sequestration potential of the forest reserve for any results-based payment projects for climate change mitigation. This is mainly due to the interventions through collaborative forest management arrangements and the pro-poor reducing emissions from Deforestation and forest Degradation (REDD+) pilot project in the landscape. This however, calls for more multi-stakeholders’ collaboration from direct resource users to national level to enhance forest conservation and reduce forest degradation for sustainable resource benefits and other ecosystem services.

Achieving high ductility and low in-plane anisotropy in magnesium alloy through a novel texture design strategy

Texture regulation is a prominent method to modify the mechanical properties and anisotropy of magnesium alloy. In this work, the Mg-1Al-0.3Ca-0.5Mn-0.2Gd (wt.%) alloy sheet with TD-tilted and circular texture was fabricated by unidirectional rolling (UR) and multidirectional rolling (MR) method, respectively. Unlike generating a strong in-plane mechanical anisotropy in conventional TD-tilted texture, the novel circular texture sample possessed a weak in-plane yield anisotropy. This can be rationalized by the similar proportion of soft grains with favorable orientation for basal <a> slip and {101¯2} tensile twinning during the uniaxial tension of circular-texture sample along different directions. Moreover, compared with the TD-tilted texture, the circular texture improved the elongation to failure both along the rolling direction (RD) and transverse direction (TD). By quasi-in-situ EBSD-assisted slip trace analysis, higher activation of basal slip was observed in the circular-texture sample during RD tension, contributing to its excellent ductility. When loading along the TD, the TD-tilted texture promoted the activation of {101¯2} tensile twins significantly, thus providing nucleation sites for cracks and deteriorating the ductility. This research may shed new insights into the development of formable and ductile Mg alloy sheets by texture modification.

Regeneration Status and Population Structure in Terai Community Forest: Evidence from Kalyankot Community Forest, Kapilvastu District, Nepal

The regeneration status of a forest is an essential metrics to assess the regeneration potential and population structure of forests. In emerging nations like Nepal, however, human dependency on forests has had a negative influence on forest diversity and sustainability. This paper analyzes the regeneration status and its link with bio-physical aspects and human disturbances. The data were collected using a systematic random sampling method and sample plots were established using the fishnet tool in ArcGIS. An inventory survey of 96 plots was carried out with nested circular sample plots with a main radius of 1261 cm. The overall regeneration condition of the forest was found to be in good condition according to Community Forestry Inventory Guideline, 2004. The majority of the tree species were determined to have a sound quality and medium (II) grades in this study. In terms of the diameter class distribution, lower diameter classes (21-60 cm) comprised more adults than the upper diameter classes (61-120 cm). This study found no significant variations in the effects of biophysical factors, such as slope and aspect, on species regeneration. The study concludes the inadequate silvicultural management interventions in the forest. This information can be useful to devise systematic plans to promote good-quality regeneration and manage the factors that are likely to affect the overall regeneration. Further research focusing on other biophysical factors as well as social factors and their influence on regeneration including its management techniques is recommended.

First Demonstration of Space-Borne Polarization Coherence Tomography for Characterizing Hyrcanian Forest Structural Diversity

Structural diversity is recognized as a complementary aspect of biological diversity and plays a fundamental role in forest management, conservation, and restoration. Hence, the assessment of structural diversity has become a major effort in the primary international processes, dealing with biodiversity and sustainable forest management. Because of prohibitive costs associated with the ground measurements of forest structure, despite their high accuracy, space-borne polarization coherence tomography (PCT) can introduce an alternative approach given its ability to provide a vertical reflectivity profile and spatiotemporal resolutions related to detecting forest structural changes. In this study, for the first time ever, the potential of space-borne PCT was evaluated in a broad-leaved Hyrcanian forest of Iran over 308 circular sample plots with an area of 0.1 ha. Two aspects of horizontal structure diversity, including standard deviation of diameter at breast height (σdbh) and the number of trees (N), were predicted as important characteristics in wood production and biomass estimation. In addition, the performance of prediction algorithms, including multiple linear regression (MLR), k-nearest neighbors (k-NN), random forest (RF), and support vector regression (SVR) were compared. We addressed the issue of temporal decorrelation in space-borne PCT utilizing the single-pass TanDEM-X interferometer. The data were acquired in standard DEM mode with single polarization of HH. Consequently, airborne laser scanning (ALS) was used to estimate initial values of height hv and ground phase φ0. The Fourier–Legendre series was used to approximate the relative reflectivity profile of each pixel. To link the relative reflectivity profile averaged within each plot with corresponding ground measurements of σdbh and N, thirteen geometrical and physical parameters were defined (P1−P13). Leave-one-out cross validation (LOOCV) showed a better performance of k-NN than the other algorithms in predicting σdbh and N. It resulted in a relative root mean square error (rRMSE) of 32.80%, mean absolute error (MAE) of 4.69 cm, and R2* of 0.25 for σdbh, whereas only 22% of the variation in N was explained using the PCT algorithm with an rRMSE of 41.56%. This study revealed promising results utilizing TanDEM-X data even though the accuracy is still limited. Hence, an entire assessment of the used framework in characterizing the reflectivity profile and the possible effect of the scale is necessary for future studies.

The Impact of Road Investments on the Forest Environment—Case Study: The Impact of Asphalt Roads on the Health Condition and Growth of Trees

The study was conducted within the framework of the R&amp;D project entitled “Environmental aspects of reconstruction and construction of forest roads using selected asphalt binders”. The aim of this study was to determine the impact of an asphalt road segment located in the Przymuszewo Forest District, the Regional Directorate of the State Forests in Toruń, Poland (53°57′24.14″ N, 17°34′38.30″ E), on growth increments and health condition of trees in a 60-year-old pine stand. The first stage of the investigation required laboratory analyses and field observations to assess the impact of mineral filler and asphalt mixtures on roadside habitats. Chemical analyses were performed on samples of wood and soil collected from transects located at three distances from the asphalt road, as well as dendrological and dendrometric analyses in circular sample plots of 0.02 ha in analogous transects parallel to the selected asphalt pavement. Analyses of soils and wood showed no negative environmental impact associated with the road. Contents of all the assayed elements in wood were lower compared to their contents in soil, which indicates their markedly reduced phytoextraction. Statistical analyses showed that the asphalt road has an effect on the adjacent forest mass, but that this effect is statistically insignificant with respect to the mean annual increments diameter at breast height and the defoliation of trees growing at various distances from the road.

Impact of Oral Diseases on Oral Health-Related Quality of Life among Older People

Context: Oral diseases are an important public health problem because of their high prevalence, their impact on individuals and society, and the expensive nature of their treatment. The oral health of the older population is a global concern. Major problems include a high prevalence of missing teeth, dental caries, periodontal disease, and wasting diseases. Poor oral health has an influence on the quality of life (QoL) as well. We attempted to assess the impact of oral diseases on oral health-related QoL (OHRQoL) using the Geriatric Oral Health Assessment Index (GOHAI) questionnaire. Aim: To investigate the impact of oral diseases on OHRQoL using the GOHAI questionnaires. Settings and Design: The study was a population-based cross-sectional survey conducted among the older populations in South Kerala. Subjects and Methods: This was a population-based cross-sectional study, in which 399 people participated: 200 were female and 199 were male. People above 60 years of age, who were permanent residents of the district, were recruited for the study. The sampling method used was circular systemic random sampling. Clinical examination was done according to the World Health Organization Oral Health Assessment Form 2013, and OHRQoL was recorded using GOHAI questionnaire. Statistical Analysis Used: Descriptive analysis was performed using frequencies of variables, such as means and standard deviations. The bivariate analysis used Student's t-test to determine the association between variables. Results: The mean age of the subjects was 65 ± 5.5 years. Significant associations were found between the psychosocial domain and missing teeth (P &lt; 0.05) and periodontitis (P &lt; 0.05). In multivariate regression analysis, an association between the pain/discomfort domain was found in denture wear (P &lt; 0.046) and tooth sensitivity (P &lt; 0.003). Conclusions: The study found a reduction in the OHRQoL among the study population. The study finding underscores the impact of oral diseases on QoL.

Phase-Dislocation-Mediated High-Dimensional Fractional Acoustic-Vortex Communication.

With unlimited topological modes in mathematics, the fractional orbital angular momentum (FOAM) demonstrates the potential to infinitely increase the channel capacity in acoustic-vortex (AV) communications. However, the accuracy and stability of FOAM recognition are still limited by the nonorthogonality and poor anti-interference of fractional AV beams. The popular machine learning, widely used in optics based on large datasets of images, does not work in acoustics because of the huge engineering of the 2-dimensional point-by-point measurement. Here, we report a strategy of phase-dislocation-mediated high-dimensional fractional AV communication based on pair-FOAM multiplexing, circular sparse sampling, and machine learning. The unique phase dislocation corresponding to the topological charge provides important physical guidance to recognize FOAMs and reduce sampling points from theory to practice. A straightforward convolutional neural network considering turbulence and misalignment is further constructed to achieve the stable and accurate communication without involving experimental data. We experimentally present that the 32-point dual-ring sampling can realize the 10-bit information transmission in a limited topological charge scope from ±0.6 to ±2.4 with the FOAM resolution of 0.2, which greatly reduce the divergence in AV communications. The infinitely expanded channel capacity is further verified by the improved FOAM resolution of 0.025. Compared with other milestone works, our strategy reaches 3-fold OAM utilization, 4-fold information level, and 5-fold OAM resolution. Because of the extra advantages of high dimension, high speed, and low divergence, this technology may shed light on the next-generation AV communication.

Analysis of Vegetation Dynamics of Tree Species inside the Forest of Institute of Forestry, Hetauda

A vegetation analysis of tree species was undertaken in the 92.69 hectares (ha) of the forest connected to the Institute of Forestry (IOF), Hetauda Campus. The study separated the forest into two strata, and a total of 10 circular sample plots (each plot measuring 500 m2) were constructed using systematic sampling with a sampling intensity of 0.5%. Enumeration of tree species was carried out within the sample plots. A total of 139 individual trees representing 16 (10 in stratum 1 and 12 in stratum 2) different tree species were recorded (60 in stratum 1 and 79 in stratum 2). Diversity indices were used for calculating vegetation parameters. According to the Importance Value Index, Shorea robusta was dominant in both strata, followed by other heterogenous species. The Shannon Wiener’s index and Simpson’s Diversity Index were higher in stratum 2, but the dominance index was lower than in stratum 1. Stratum 2 had a marginally higher measure of both evenness and richness than stratum 1. The study investigated the vegetation structure of the riverine and tropical moist deciduous forest in the study area. Increasing human interference had no significant effect on diversity and number of species among the strata. This study provides the baseline data necessary to characterize the phytodiversity of the forest area of the Institute of Forestry, Hetauda Campus for conservation and sustainable management.

A prototype microfluidic paper-based chromatic device for simultaneous determination of copper(II) and zinc(II) in urine

The present work proposes the development of a simple and easy-to-make microfluidic paper-based analytical device (µPAD) as a prototype chromatic device for the simultaneous determination of copper and zinc in urine. The µPAD comprises a main circular sampling zone with two identical arms, each containing a circular pretreatment zone and a circular detection zone. Copper(II) and zinc(II) react with 1-(2-pyridylazo)-2-naphthol (PAN) reagent, at pH 6.0 and room temperature, to form chelates colored red and pink, respectively, that can be quantified by digital imaging analysis. The colorimetric reaction sensitivity significantly improved by coating the paper substrate surface with 5% 3-aminopropyltriethoxysilane (APTES) and applying three successive additions of standard or sample onto the sampling zone, without any prior sample preparation step. These combined analytical strategies increased the color intensity of the metal chelates formed on µPAD surface, allowing to detect the desired elements at trace level concentrations. The reaction interferences associated with the presence of foreign elements were eliminated or reduced through the addition of masking agents at different concentrations for each case. Under optimized conditions, excellent linear relationships were obtained in the range 0.1−10 µg mL−1, with determination coefficients (R2) greater than 0.9957. The limits of detection (LOD) and quantification (LOQ), respectively, were 27.1 µg L−1 and 90.3 µg L−1 for copper and 35.9 µg L−1 and 119.7 µg L−1 for zinc. The developed prototype device was validated by analyzing urine certified material samples, obtaining a good concordance without significant difference between the certified values and the measured values. Its application for clinical analysis offers simple, quick, cheap, noninvasive, and environmentally friendly measurements, which are desirable analytical features for point-of-care testing.

Determinant of farmers’ participation and biodiversity status in the program of agroforestry rehabilitation in Sudan

Abstract. Hemida M, Mulyana B, Vityi A. 2022. Determinant of farmers’ participation and biodiversity status in the program of agroforestry rehabilitation in Sudan. Biodiversitas 23: 5638-5645. The agroforestry Rehabilitation Program (ARP) was launched in Nabag Reserve Forest (NRF), Sudan, to rehabilitate the forest cover and improve livelihoods for communities around the forest. To enhance the efficacy of such rehabilitation programs, it is crucial to understand the impact of various factors on community perception of participation in forest rehabilitation. The objectives of this study were to (i) examine the factors that influence farmers’ perceptions of their involvement in the program and (ii) assess the biodiversity of trees and crop species in the program. Data was gathered through a survey that included personal interviews with 200 farmers who participated in the program. A total of 250 circular sample plots were established randomly to achieve the second objective. The results showed that extension services, farming experience, family members, educational level, land size, and gum Arabic production positively influence farmers’ perceptions. The study findings identified nine tree species and five crop species in NRF. The dominant tree species were Acacia senegal and Balanites aegyptiaca which represented 62.8% and 12.4 % of the total species, respectively. At the same time, groundnut and watermelon were identified as favorite crops cultivated by farmers. Furthermore, the non-rehabilitated area has shown better value in richness, heterogeneity, and evenness than the rehabilitated areas.

Estimation of the Mean Trace Length of Discontinuities in an Underground Drift Using Laser Scanning Point Cloud Data

In the drifts of underground metal mines, the extraction of rock mass discontinuity characteristics from point cloud models generated with laser scanning has become the main approach. However, the exposure of discontinuities is restricted in drifts, and the size of discontinuities cannot be measured directly. Therefore, it is necessary to use a reasonable sampling tool to estimate the mean trace length of the discontinuities that are mapped in the point cloud model. In this paper, a method to estimate the mean trace length of discontinuities using a three-dimensional (3D) model of a drift (3DM) is proposed. Through the point cloud data of a drift obtained using 3D laser scanning, the information on discontinuities in the surrounding rock was extracted; then, the mean trace length was estimated using 3DEC to set sampling windows on the roof and sidewall in the 3DM. By analyzing the difference between the circular sampling window and the rectangular sampling window using simulated cases, the estimation results showed that the mean trace length obtained using circular measuring windows in the 3DM was closer to the true trace length. Finally, the method was used in a practical engineering case in Jianshan Iron Mine, Panzhihua, Sichuan, China.