Block Method Research Articles

Relationship between blasting operation and slope stability: a case study at Borneo Indo Bara open pit coal mine

Bench blasting is commonly used in open-pit coal mines because it effectively increases coal production and aids in overburden removal. However, uncontrolled blasting can generate significant vibrations and accelerations, which may lead to slope failure if the magnitude of permanent displacement exceeds its critical value. A prevalent method for calculating the dynamic factor of safety (FoS) of a slope due to blasting is the pseudo-static approach; however, this method tends to be overly conservative. In this study, we utilized Newmark’s sliding block method and the strength reduction factor (SRF) to assess the dynamic FoS of slopes by evaluating the permanent displacement caused by bench blasting. We based our seismic input on a complete vibration waveform obtained through signature hole analysis of a specific bench blast design. The dynamic FoS was defined as the SRF threshold that resulted in a critical slope displacement of 50 mm. The case study was conducted at Borneo Indo Bara, one of Indonesia’s largest open-pit coal mines located in South Borneo Province. We analyzed four sidewall slopes that were subjected to repeated blasting events. The results indicated that the slope’s LOM design could tolerate blasting vibrations corresponding to a peak particle acceleration (PPA) of up to 0.41 g, which yielded a dynamic FoS of 1.35. This value is significantly higher than the pseudo-static approach, which indicated a pseudo-static FoS of 1.04 for a PPA of 0.12 g. Furthermore, this study assists mining practitioners in predicting the allowable number of blast events to prevent slope failure and recommends avoiding blast events with a scaled distance of less than 8 m/kg1/2 to prevent sudden slope failures. In conclusion, the study highlights the importance of the integrated approach that combines signature hole analysis, Newmark’s sliding block method, and the SRF approach for evaluating the dynamic FoS of mine slopes subjected to bench blasting. The results of this study can offer valuable insights for mining engineers engaged in bench blasting to adopt the proposed integrated approach, which is still overlooked in Indonesia’s open pit blasting practices.

Efficient One-Step Second Derivative Block Numerical Scheme for Solution of first-Order Integro-differential Equations

In this work, a new class of one-step second derivative block hybrid numerical scheme is developed for the numerical solution of first-order integro-differential equations with the aid of Simpson's 1/3 quadrature method. The collocation techniques is used for the derivation of this new block method which gives high order of accuracy with very low error constants and its zero stable and convergent. The results from the numerical solution of the examples drawn from literature shows its efficiency in terms of the small errors obtained.

RESEARCH ON THE CONTROL OF THE SPECIES AMBROSIA ARTEMISIIFOLIA IN THE SUNFLOWER CULTURE IN THE NORTH-WEST AREA OF ROMANIA

The primary objective of this research was to determine the most suitable herbicides, the most effective doses, and the optimal timing for the control of ragweed in sunflower crops. In 2024, an experiment was conducted at the Livada Agricultural Development Research Station, using the randomized block method with 10 variants in 3 repetitions, on an albic Luvisol soil with a pH of 5.1, a clay content of 20.9%, and a humus content of 1.8%.

Effect of WW-domain transcription regulator 1 on aging regulation of human dental pulp stem cells

Objective: Investigating the changes of phenotype and moleculars associated with aging with the increase of passage times of human dental pulp stem cells (hDPSC), to explore the role of WW-containing transcriptional regulator 1 (WWTR1) in the aging mechanism. Methods: hDPSCs were cultured by tissue block method, and were divided into 4 groups according to the age, algebra, cell knockdown and overexpression of WWTR1 in hDPSCs. Group I: hDPSCs from human teeth were further divided into youth group (15-25 years old) and group middle-aged group (40-50 years old)] according to different ages. Group Ⅱ: according to different passage, hDPSCs were divided into young cells group (hDPSCs were transmitted to P3 generation), and old cells group (hDPSCs were transmitted to P10 generation). Group Ⅲ: hDPSCs were knocked down of WWTR1, which were further divided into knockdown group (sh-WWTR1) and knockdown carrier group (sh-NC). Group Ⅳ: hDPSCs were overexpressed of WWTR1, which were further divided into overexpression group (OE-WWTR1) and overexpression carrier group (OE-NC). Real-time quantitative fluorescent PCR (RT-qPCR) was used to detect the changes of WWTR1 expression in groups Ⅰ and Ⅱ, and cell counting kit-8 (CCK-8) was used for groups Ⅱ, Ⅲ, and Ⅳ. Cell proliferation capacity was detected by CCK-8 assay. The ability of osteogenic differentiation was detected by alizarin red staining. Cell senescence positive rate was detected by age-related β-galactosidase staining. The expression levels of age-related genes p53 and p21 were detected by RT-qPCR. Results: The proportion of senescent cells increased gradually with continuous culture. The proliferation and osteogenic differentiation of hDPSCs in the old group were significantly lower than those in the young group (P<0.001). The expression levels of senescence related genes p53 (2.09±0.24) and p21 (4.91±0.54) in old cell group were higher than those in young cell group respectively [p53: (1.08±0.09) and p21: (1.09±0.08)] (P<0.01, P<0.001). The WWTR1 expression levels of hDPSCs in middle-aged group and old cells group were both decreased compared with those in young group and young cells group (P<0.01). The proportion of senescent cells in knockdown group (44.50±2.42) was higher than that in knockdown carrier group (22.27±0.56) (P<0.001). After knocking down WWTR1 in hDPSCs, the expression levels of age-related genes p53 and p21 were up-regulated (P<0.001), and the abilities of proliferation and osteogenic differentiation in the knockdown group were lower than those in the knockdown carrier group (P<0.001). The proportion of senescent cells in overexpression empty carrier group (20.4±0.79) was higher than that in overexpression group (10.07±0.61) (P<0.001). After WWTR1 overexpression ins hDPSCs, the expression levels of age-related genes p53 and p21 were down-regulated, and the proliferation and osteogenic differentiation ability in overexpression group were higher than those in OE-NC group (P<0.001). Conclusions: WWTR1 can inhibit the expression levels of age-related genes p53 and p21, thus delaying the aging process as well as promoting the proliferation and osteogenic differentiation of hDPSCs.

The efficacy of transversalis fascia plane block in pediatric inguinal herniotomy: a randomized controlled study.

The post-operative analgesic efficacy of transversalis fascia plane (TFP) block is controversial in pediatric patients undergoing herniotomy. This study aims to compare the efficacy of TFP block and standard analgesic methods. Sixty patients aged 1-8 years who underwent the open procedure of herniotomy were randomly divided into two groups TFP block (n = 30) or control group (n = 30). The TFP group received 0.25% bupivacaine at 0.5 mL/kg. Routine analgesia protocol was applied to Group C. Pain scores (FLACC), family satisfaction, block complications, nausea, sedation score, and additional analgesic requirements were recorded. FLACC pain scores at post-anesthesia care unit (PACU), 1st, 2nd, and 4th h were statistically significantly lower in Group TFP compared to group control (p < 0.05). Three patients in Group TFP and 12 in group control required rescue analgesics at PACU (p = 0.015). Ibuprofen was required in two patients in Group TFP and 11 in Group Control (p = 0.010). Parental satisfaction is higher in the TFP group than in Group Control (p < 0.001). There was no statistically significant difference between the groups in terms of post-operative nausea and sedation scores (p > 0.05). We conclude that TFP block in pediatric patients is an appropriate approach as a part of multimodal analgesia. It creates fewer pain scores in the early post-operative period, requires less additional analgesia, and increases family satisfaction.

Comparing Analgesic Efficacy: Ropivacaine with Dexamethasone vs. Ropivacaine with Dexmedetomidine After Cesarean Section Using Transversus Abdominis Plane Block (2020 - 2021)

Background: There are several methods for managing postpartum pain. The combined use of drugs with anesthetics can lead to effective pain management. Objectives: The present study aimed to compare the analgesic effects of ropivacaine (RPV) + dexamethasone (DEXA) and RPV + dexmedetomidine (DEX) on pain after cesarean section (CS) using the transversus abdominis plane (TAP) block. Methods: This double-blind, randomized clinical trial employed a quadruple block randomization method and included 40 participants scheduled for CS at Ayatollah Mousavi Hospital in Zanjan, Iran, during 2020 - 2021. The participants were divided into two groups: The first group received 15 mL of RPV 2% combined with 100 µg of DEX via the bilateral TAP block method, while the second group received 15 ml of RPV 2% combined with 8 mg of DEXA. The analgesic effects of the two drug combinations were evaluated at 0, 3-, 6-, 12-, and 24-hours post-CS using the visual analog scale (VAS) to measure pain intensity. Data analysis was conducted using SPSS software, version 24. Results: In the RPV + DEX group, the onset of pain was delayed, resulting in a longer duration before the administration of painkillers (P = 0.041 and P &lt; 0.001). However, pain intensity between 3- and 24-hours post-surgery was significantly higher in the RPV + DEX group compared to the RPV + DEXA group (P = 0.028, P &lt; 0.001). The RPV + DEX group experienced longer durations before the onset of pain and the need for painkillers (P = 0.041, P &lt; 0.001). Hypotension was more frequently observed in the RPV + DEXA group at 0 hours (P = 0.068) and 3 hours post-surgery (P = 0.003). Additionally, bradycardia and sedation incidences were higher in the RPV + DEXA group at 3 hours post-surgery (P = 0.005, P = 0.048). Conclusions: The use of RPV + DEXA, unlike RPV + DEX, demonstrated positive and significant effects on pain management in female CS candidates using the TAP block method, despite its side effects.

Clinical effectiveness of guided breathing exercises in reducing anxiety, stress, and depression in COVID-19 patients

The COVID-19 pandemic has led to an increase in the prevalence of anxiety, stress and depression among affected people. This study was conducted with the aim of investigating the clinical effectiveness of guided breathing exercises in reducing anxiety, stress and depression in patients with COVID-19. A quasi-experimental study design was used, involving a sample of COVID-19 patients who underwent guided breathing exercises as a complementary therapy. After simple sampling, eligible subjects were randomly divided into two groups: intervention (30 patients) and control (30 patients) using random block method. The Depression Anxiety Stress Scale-21 (DASS-21) questionnaire was administered before and after the intervention to evaluate changes in anxiety, stress, and depression levels. The results of this study demonstrated that clinically guided breathing exercises had a significant effect on reducing anxiety and stress in COVID-19 patients. The intervention significantly reduced anxiety and stress scores (p < 0.001). However, there was no significant reduction in depression scores among patients who participated in guided breathing exercises (p = 0.946). Guided breathing exercises are an effective complementary technique in reducing the level of anxiety and stress in COVID-19 patients. Moreover, the exercises may provide a worthy non-pharmacological approach to managing psychological distress in COVID-19 patients.

Effect of different surface conditioning methods and low pH solutions on the shear bond strength of orthodontic brackets to newly introduced CAD/CAM materials

AimTo evaluate the shear bond strength (SBS) of ceramic and metallic orthodontic brackets bonded to lithium disilicate ceramics or hybrid ceramics and subjected to different surface conditioning treatments. Materials and methodsIn total, 300 specimens were fabricated from GC LiSi (lithium disilicate) and GC Cerasmart (hybrid) ceramic blocks. The specimens were divided into four groups according to the following surface treatments: hydrofluoric acid (HF); sandblasting with 50 μm aluminum oxide; Monobond Etch and Prime; and erbium-doped yttrium aluminum garnet (Er-YAG) laser. Metal (Victory Series) and ceramic (Clarity) brackets were bonded using an orthodontic adhesive resin (Transbond XT; 3M Unitek, CA, USA). The specimens were then stored in three different mediums (artificial saliva, mouth rinse, and gastric juice) and thermocycled. An SBS test was performed after 1 week. The surface morphology was examined after the conditioning treatments using a scanning electron microscope. Data were analyzed using analysis of variance, t-test, and Duncan test. ResultsThe SBS data revealed that the type of computer-aided design/computer-aided manufacturing (CAD/CAM) block and surface conditioning method significantly affected the SBS. The highest SBS was recorded (10.112 MPa) for the HF-treated hybrid ceramic blocks stored in the saliva medium, while the lowest SBS (1.862 MPa) was reported for the Er-YAG laser-treated lithium disilicate ceramic blocks stored in the gastric juice medium. GC Cerasmart exhibited better bond strength than that of GC LiSi; however, no significant difference was observed between the ceramic and metal brackets. ConclusionThe CAD/CAM material, surface conditioning method, and medium affect the SBS.

ANALISIS POLA DISTRIBUSI CURAH HUJAN LEBAT DOMINAN DI DAERAH ALIRAN SUNGAI (DAS) CITANDUY HULU

Rainfall plays an important role in hydrological and environmental planning. Meteorological conditions affect rainfall through its intensity, amount, and duration. However, heavy rainfall can cause significant damage and loss. Research was conducted in the Upper Citanduy watershed, West Java, using rainfall data from 8 stations over a range of 5–14 years. The study took a heavy rainfall event threshold of ≥ 50 mm in 24 hours. The research aims to analyze the dominant heavy rainfall patterns in the Upper Citandyu watershed. Empirical analysis used the Mononobe Method and Alternating Block Method (ABM), while rainfall distribution was analyzed with Inverse Distance Weighted (IDW) using Geographic Information Systems. The dominant heavy rainfall duration in the Upper Citanduy watershed occurred over 4–6 hours. Rainfall distribution analysis showed a pattern that was not influenced by the elevation of the rainfall station. The analysis results show that the Mononobe Method is closer to the dominant observed heavy rainfall distribution for 4 hours, while ABM is closer to the durations of 5 and 6 hours. The suitability of the distribution pattern was measured using Correlation (r), Root Mean Squared Error (RMSE), and Nash-Sutcliffe Efficiency (NSE) criteria, with Mononobe providing better results than ABM method. This research contributes to the understanding of rainfall patterns that can form the basis for analyzing designed rainfall intensity as a step in flood disaster mitigation in the Upper Citanduy watershed.Keywords: heavy rainfall, rainfall distribution pattern, rainfall intensity, upper Citanduy watershed, geographic information system

Block method of mining quarry fields as a tool to reduce environmental impact in conditions of intensification of production

Relevance. The intensification of open-pit mining in the coal basins of the Russian Federation is accompanied by an increase in negative impact on the environment. Directly in Kuzbass, the environment is exposed to the impact of the coal industry, especially when conducting open-pit mining using deep mining systems, with external dumping, which is accompanied by the withdrawal of a large amount of undisturbed land. The block method of mining quarry fields, well known in mining, has been rarely implemented in existing and planned quarry fields. The general line of its application is the lack of a unified approach to the design of block parameters, including environmental and economic assessment of the impact of this technological solution on the environment. Aim. Reduce environmental payments of mining enterprises with justified parameters of blocks for the development of quarry fields of promising inclined and steeply dipping coal deposits. Methods. Systematic generalization of the actual situation of mining operations in open-pit mines using the block method of mining quarry fields, the method of options and technical and economic modeling using spreadsheets. Results and conclusions. The authors have proposed the ecological and economic criteria for assessing the application of the block method of quarry field development. This allows us to study the patterns of change in environmental indicators. Using the example of the Krasnobrodskoe open-pit mine, the costs of environmental payments for the use of land resources, emissions and dusting are calculated for two options different from the design documentation. Based on the calculation results, the authors proved the efficiency of applying the block procedure for developing promising coal deposits, allowing us to reduce the costs for environmental impact by 22.5 and 63%, respectively, when changing the length of the initial block along the bottom from 2.2 to 1.4 km. From which it follows that the combined ecological and economic indicators allow us to fully assess the feasibility of applying the method for calculating block parameters, which is generally reflected in reduction in the costs for negative impact on the environment.

A Chebyshev Generated Block Method for Directly Solving Nonlinear and Ill-posed Fourth-Order ODEs

This study presents a block method induced by Chebyshev polynomials of first kind for directly solving initial value problems of fourth-order ordinary differential equations without reducing the problems to a system of first-order differential equations. The method was developed by applying interpolation and collocation procedures to a Chebyshev approximate polynomial. The unknown parameters were obtained using the Gaussian elimination method, then substituted into the approximate solution to get the continuous scheme and evaluated at the selected point to give the discrete scheme. The method was zero stable, consistent, and convergent, p-stable as shown by the region of absolute stability and has an order of seven. The accuracy and usability of the developed method were tested by applying it to solve six numerical examples. The method was found to be efficient as it gives minimal error. The numerical results of the method were compared with other works cited in the literature and found to be better as it gives minor errors.

A Six-Point y-Function Hybrid Block Method for Direct Solution of Third Order Ordinary Differential Equations

In this article, a new continuous numerical method was developed for the numerical integration of general third-order initial value problems (IVPs) of ordinary differential equations (ODEs). The method was derived by adopting interpolation and collocation approach using a combination of power series and exponential functions as the basis function for the approximate solution to the ODEs. The approximate solution was interpolated at both nodal and off-nodal points while the differential systems from the approximate solution was collocated at all nodal points to obtain the set of methods with given step-numbers. This derived approach ensured that the hybrid points are obtained at the y-values of the methods. This class of hybrid linear multi-step method satisfied the conditions for usability and accuracy of any given method. These conditions were confirmed by testing the consistency, stability and convergence of the developed method. The method was applied to solve directly linear and non-linear third order ODEs without reduction to system of first-order ordinary differential equations. Results from the computation compared favorably with some existing numerical methods in literature with comparable properties to confirm the superiority of the newly developed method.

A transcriptomic analysis of dental pulp stem cell senescence in vitro

Background/purposeThe use of human dental pulp stem cells (hDPSCs) as autologous stem cells for tissue repair and regenerative techniques is a significant area of global research. The objective of this study was to investigate the effects of long-term in vitro culture on the multidifferentiation potential of hDPSCs and the potential molecular mechanisms involved.Materials and methodsThe tissue block method was used to extract hDPSCs from orthodontic-minus-extraction patients, which were then expanded and cultured in vitro for 12 generations. Stem cells from passages three, six, nine, and twelve were selected. Flow cytometry was used to detect the expression of stem cell surface markers, and CCK-8 was used to assess cell proliferation. β-Galactosidase staining was employed to detect cellular senescence, Alizarin Red S staining to assess osteogenic potential, and Oil Red O staining to evaluate lipogenic capacity. RNA sequencing (RNA-seq) was conducted to identify differentially expressed genes in DPSCs and investigate their potential mechanisms.ResultsWith increasing passage numbers, pulp stem cells showed an increase in senescence and a decrease in proliferative capacity and osteogenic–lipogenic multidifferentiation potential. The expression of stem cell surface markers CD34 and CD45 was stable, whereas the expression of CD73, CD90, and CD105 decreased with increasing passages. According to the RNA-seq analysis, the differentially expressed genes CFH, WNT16, HSD17B2, IDI1, and COL5A3 may be associated with stem cell senescence.ConclusionIncreased in vitro expansion induced cellular senescence in pulp stem cells, which resulted in a reduction in their proliferative capacity and osteogenic–lipogenic differentiation potential. The differential expression of genes such as CFH, WNT16, HSD17B2, IDI1, and COL5A3 may represent a potential mechanism for the induction of cellular senescence in pulp stem cells.

A-4 Step Chebyshev Based Multiderivative Direct Solver For Third Order Ordinary Differential Equations

This paper develops and examines a uniform order, 4 step block method with Chebyshev series as bases function. Collocation and interpolation technique was used to modeled implicit discrete schemes from continuous scheme to derive our block. The block method obtained was of order 4. It is consistent, zero stable and consequently zero stable. The results obtained from four test problems shown that the method converges to exact solutions and perform better than some existing methods in the literatures.

Short-term results of unroofing and marsupialization compared to the Karydakis technique in the treatment of pilonidal sinus. A randomized prospective study

IntroductionThe treatment of pilonidal sinus (PS) is usually surgical, but no procedure is considered the gold standard. The Karydakis (K) technique is widely used, and unroofing and marsupialization (UM) is a simple surgery with good results. Primary objectiveTo evaluate early postoperative complications (EPC) 30 days after UM surgery compared to the K technique. Secondary objectivesTo evaluate surgical time, postoperative pain, patient satisfaction, return to daily activity and early recurrence within 3 months. MethodProspective, single-center, randomized study in patients who underwent surgery for primary PS with no abscess between June 2016 and November 2017. They were randomized using a computer-generated block method. To analyze the main objective, a non-inferiority analysis was performed. Results122 patients with symptomatic primary PS were randomized: 60 in the K group and 62 in the UM group. Both groups were homogeneous.There were statistically significant differences between surgery and postoperative complications at 15 and 30 days in favor of UM. There were also differences in favor of UM in surgical time and return to daily activity. During the 90-day follow-up, there were 3 recurrences in the UM group and 0 in the K group. ConclusionsUM is a simple, minimally invasive, easily reproducible technique that has a lower rate of early complications, with a shorter operative time and an earlier return to daily activity.

Unveiling the Multifaceted GRB 200613A: Prompt Emission Dynamics, Afterglow Evolution, and the Host Galaxy’s Properties

We present our optical observations and multiwavelength analysis of the GRB 200613A detected by the Fermi satellite. Time-resolved spectral analysis of the prompt gamma-ray emission was conducted utilizing the Bayesian block method to determine statistically optimal time bins. Based on the Bayesian Information Criterion, the data generally favor the Band+blackbody (BB) model. We speculate that the main Band component comes from the Blandford–Znajek mechanism, while the additional BB component comes from the neutrino annihilation process. The BB component becomes significant for a low-spin, high-accretion-rate black hole central engine, as evidenced by our model comparison with the data. The afterglow light curve exhibits typical power-law decay, and its behavior can be explained by the collision between the ejecta and the constant interstellar medium. Model fitting yields the following parameters: EK,iso=(2.04−1.50+11.8)×1053 erg, Γ0=354−217+578 , p=2.09−0.03+0.02 , n18=(2.04−1.87+9.71)×102 cm−3, θj=24.0−5.54+6.50 degree, ϵe=1.66−1.39+4.09)×10−1 and ϵB=(7.76−5.9+48.5)×10−6 . In addition, we employed the public Python package Prospector to perform a spectral energy distribution modeling of the host galaxy. The results suggest that the host galaxy is a massive galaxy ( log(M*/M⊙)=11.75−0.09+0.10 ) with a moderate star formation rate ( SFR=22.58−7.22+13.63M⊙ yr−1). This SFR is consistent with the SFR of ∼34.2M ⊙ yr−1 derived from the [O ii] emission line in the observed spectrum.

Hyperbaric Treatment Stimulates Chaperone-Mediated Macroautophagy and Autophagy in the Liver Cells of Healthy Female Rats.

The role of autophagy goes far beyond the elimination of damaged cellular components and the quality control of proteins. It also cleanses cells from inclusions, including pathogenic viruses, and provides energy-forming components. The liver, which is an organ with increased metabolism, is made up of cells that are particularly vulnerable to damage. Therefore, detoxification of liver cells in the process of autophagy has become a very important issue clinically. The aim of this study was an immunohistochemical evaluation of proteins activated in rat liver cells at different stages of hyperbaric autophagy. The rats used for the study were randomly divided into six equivalent groups-three control groups and three experimental groups. Animals from the experimental groups were subjected to hyperbaric treatment in a hyperbaric chamber, with a pressure of 1.6 ATA for 120 min. They breathed atmospheric air. Rats were decapitated within 5 or 10 days after removal from the chamber. Immunohistochemical reactions with beclin 1, LC3B, RAB7, and HSC73 proteins were carried out on preparations made from liver slices. A three-step labeled streptavidin-biotin detection method of paraffin blocks (LSAB three-step) was used for immunohistochemical research. The results were evaluated using computer programs for morphometric analysis of microscopic images by calculating the mean surface areas occupied by a positive immunohistochemical reaction in individual groups for all antibodies tested. Increased closure of substrates in the autophagosome (beclin 1) induced late endosome transport and accelerated autophagosome maturation process (RAB7). Furthermore, a larger number of autophagosomes (LC3B) was observed in liver cells immediately after the cessation of hyperbaric activity; however, this decreased after 5 days. During this time, chaperone-mediated autophagy (HSC73) was observed on a larger scale. This means that increased macroautophagy induced by hyperbaric treatment weakens with time that has elapsed since the cessation of high pressure, whereas similarly induced chaperone-mediated autophagy intensifies over time.

Exploring Locality Sensitive Hashing as a Blocking Method for Large-Scale Administrative Datasets

ObjectivesLinking large-scale datasets is challenging due to the computational power required. This research explores using Locality-Sensitive-Hashing (LSH) as a novel blocking method to facilitate linking large administrative data. LSH uses an efficient technique of hashing data while preserving similarity, reducing the search space and processing power required to find links. ApproachSamples were taken from a gold-standard dataset and blocked using LSH. Various parameters were tested to establish LSH’s optimal performance at retrieving linked pairs and reducing the search space size. ResultsTesting the method on small datasets gave promising results, with the LSH method creating ~9,000 candidate pairs. This is a improvement over our traditional blocking method or cartesian product, which created ~70,000 and 23.4 million candidate pairs, respectively. We have therefore shown that LSH can significantly reduce the search-space size. A further advantage of the method is its capability in handling alternative variables such as those that may be present in longitudinal or composite data, without needing to manually anticipate the different combinations of variables which may occur. Variable formats to simulate agreement weighting were also considered, with encouraging results. Conclusion and ImplicationsOur research shows that LSH can be used to drastically reduce the search space when blocking for data linkage This suggests developing LSH as a blocking method could result in more effective blocking, quicker linkage, and no loss of quality compared to traditional methods. However, further research on increasing the method’s scale is necessary.

Comparison of two methods of greater occipital nerve block in patients with chronic migraine: ultrasound-guided and landmark-based techniques

BackgroundMigraine is a primary headache defined as moderate-to-severe pain lasting 4 to 72 h, ranking 2nd among the disabling conditions for both genders regardless of the age and the greater occipital nerve (GON) block has been reported as an efficient treatment method for migraine. The present study aims to evaluate and compare the efficiency of the two methods of GON block, i.e., the ultrasound (US)-guided technique and the landmark-based technique.MethodHaving a prospective and randomized design, the study assigned the patients with chronic migraine into two groups after which a neurologist performed landmark-based GON block in the first group while an algologist performed US-guided GON block in the second group. During the 3-month follow-up period, the number of days with pain, the duration of pain, the number of analgesic drugs taken in a month, and Visual Analogue Scale (VAS) scores were compared with the values ​​before treatment and at the 1st week, 1st month, and 3rd month after treatment.ResultsUS-guided GON block group included 34 patients while there were 32 patients in the landmark-based GON block group. US-guided GON block group showed significantly reduced VAS scores and frequency of attacks compared to the landmark-based GON block group at Month 1 after the procedure. After a 3-month follow-up period of the two groups, the frequency of attacks, analgesic intake and the duration of attacks were lower in both groups compared to the baseline. At 3-month follow-up, the mean of VAS scores decreased from 9,47 ± 2,69 to 4,67 ± 1,9 in US-guided GON block group and from 9,46 ± 0,98 to 7 ± 2,5 in the landmark-based GON block group.ConclusionIt was determined that both US-guided and landmark-based GON block were efficient techniques in patients with chronic migraine. US-guided GON block technique resulted in lower VAS scores, shorter durations of pain, lower frequencies of attack, and lower intake of analgesics compared to the landmark-based GON block technique.

Hybrid block formulae whose eigenvalues of Jacobian matrices are close to the imaginary axis of the complex plane

Methods for integrating stiff initial value problems are required to be A-stable. Of great interest are A-stable methods whose Jacobian matrices have their eigenvalues close to the imaginary axis of the complex plane. This class of A-stable methods are very rare. This paper is on the development of a new family of A-stable hybrid block method whose Jacobian matrices possess eigenvalues on the imaginary of the complex plane via interpolation and collocation techniques. The family of methods developed herein are A-stable for order p ≤ 18. Numerical solutions generated by the new method are compared with existing methods in the literature. The numerical results show that the new class of methods are more efficient and accurate.