Single Block Research Articles

Structural diversity and distribution of NMCP-class nuclear lamina proteins in streptophytic algae.

Nuclear Matrix Constituent Proteins (NMCPs) in plants function like animal lamins, providing the structural foundation of the nuclear lamina and regulating nuclear organization and morphology. Although they are well-characterized in angiosperms, the presence and structure of NMCPs in more distantly related species, such as streptophytic algae, are relatively unknown. The rapid evolution of NMCPs throughout the plant lineage has caused a divergence in protein sequence that makes similarity-based searches less effective. Structural features are more likely to be conserved compared to primary amino acid sequence; therefore, we developed a filtration protocol to search for diverged NMCPs based on four physical characteristics: intrinsically disordered content, isoelectric point, number of amino acids, and the presence of a central coiled-coil domain. By setting parameters to recognize the properties of bona fide NMCP proteins in angiosperms, we filtered eight complete proteomes from streptophytic algae species and identified strong NMCP candidates in six taxa in the Classes Zygnematophyceae, Charophyceae, and Klebsormidophyceae. Through analysis of these proteins, we observed structural variance in domain size between NMCPs in algae and land plants, as well as a single block of amino acid conservation. Our analysis indicates that NMCPs are absent in the Mesostigmatophyceae. The presence versus absence of NMCP proteins does not correlate with the distribution of different forms of mitosis (e.g., closed/semi-closed/open) but does correspond to the transition from unicellularity to multicellularity in the streptophytic algae, suggesting that an NMCP-based nucleoskeleton plays important roles in supporting cell-to-cell interactions.

Ultrasound-guided suprascapular nerve block with lidocaine vs. saline combined with physical exercises for the rehabilitation of supraspinatus tendinitis: a randomized double-blind controlled trial

IntroductionShoulder pain is the third leading cause of musculoskeletal complaints in primary care clinics. Its prevalence varies from 14% to 34%. Among all the structures that can cause shoulder pain, the most vulnerable to injury is the tendon of the supraspinatus muscle. The ideal management protocol is still unknown. To date, little is known in the literature about the use of ultrasound-guided suprascapular nerve block as a treatment for supraspinatus muscle tendinitis. Our objective was to assess the effects of the association of a single ultrasound-guided suprascapular nerve block combined with home-based rotator cuff exercises to reduce pain and improve shoulder functioning in patients with supraspinatus tendinitis.MethodsWe evaluated the effect of a single ultrasound-guided suprascapular nerve block on pain and functioning of people with supraspinatus tendinitis. Diagnosis was performed using the positive Jobe test. Due to large disparity between clinical and radiological findings, only clinical diagnostic criteria were used to select patients. This was a double-blind, randomized, controlled, clinical study in which patients in the intervention group (n = 42) received a single injection of 5 ml of 2% lidocaine, while in the control group (n = 41) patients underwent the same procedure receiving saline solution 0.9%. All patients received face to face instructions by an experienced physiotherapist and a leaflet explaining home-based exercises. Pain and functioning were assessed using the Shoulder Pain and Disability Index (SPADI) questionnaire before the procedure, one week and 12 weeks after the procedure.ResultsPatients in both groups improved significantly since the initial evaluation until the 12th week. Intervention group SPADI (pre, 1 week, 12 weeks): 75.80 ± 18.96, 56.25 ± 31.37, 46.31 ± 31.41 (p < 0.001); Control group SPADI: 75.49 ± 16.67, 50.51 ± 27.58, 49.37 ± 30.90 (p < 0.001). However, there were no significant differences between groups (p = 0.291).Discussion/conclusionWe concluded that both lidocaine and saline ultrasound-guided suprascapular nerve blocks reduce pain and improve shoulder functioning in patients with supraspinatus tendinitis. Unexpectedly, the same block performed with saline showed similar results and effects. Clinical Trial RegistrationClinicalTrials.gov, identifier [NCT02495818].

Combined SK and K2P channel block cardioverts atrial fibrillation in 82% of cases, doubling the efficacy of single channel block

Abstract Background Inhibiting the atrial-selective SK and K2P channels represents a promising strategy for cardioverting atrial fibrillation (AF), but its efficacy has not been evaluated in a large human cohort. Objectives This study employed in-silico trials in 1000 virtual patients (i.e., clinical trials conducted in a population of virtual human subjects through modelling and simulation) to estimate the efficacy and safety of three pharmacological interventions: single and combined SK and K2P channel block. Methods A large cohort of 1000 virtual patients was developed based on human data, to cover the electrophysiological, anatomical and structural variability encountered in clinical practice. The subset of virtual patients with AF maintenance underwent pharmacological cardioversion (Figure). Results Sustained AF was observed in 654 (65%) virtual patients. In this cohort, cardioversion efficacies of 33% (213 of 654), 43% (278 of 654) and 82% (534 of 654) were obtained for single SK, single K2P and combined channel block, respectively (Figure). The cardioversion efficacy was proportional to an increase in tissue refractoriness (increase of 45.2±43.0, 71.0±55.3 and 133.0±48.4 ms in the atrial refractory period) and depended on the ionic current profile. Virtual patients cardioverted by SK channel block presented lower K2P densities (0.008±0.002 vs. 0.006±0.002 S/mF; non-cardioverted vs. cardioverted virtual patients, respectively). Similarly, a lower SK density favoured the success of K2P channel inhibition (1.87±0.24 vs. 1.46±0.5 S/mF; non-cardioverted vs. cardioverted virtual patients, respectively). Both ionic currents had a crucial role on atrial repolarization, and thus, a synergism resulted from the polypharmacological strategy (i.e., higher efficacy than the additive effects of single channel block). All three interventions, including the multi-channel block, preserved the atrial electrophysiological function (i.e., conduction velocity and calcium transient dynamics) and thus, the atrial contractile properties (safety). Conclusion In-silico trials identify the polypharmacological SK+K2P channel block as an effective and safe strategy for AF management.

Per Segment Plane Sweep Line Segment Intersection on the GPU

Polygon overlay operations are used for various purposes such as GIS searches and queries, VLSI and basic geometric operations of intersection, union and difference. There have been recent research articles presenting algorithms using the GPU to perform line segment intersection for geometric operations. We present two parallel algorithms implemented on the GPU that focus on the active list portion of the traditional serial plane sweep algorithm. The first algorithm uses a single block of threads to simulate the active list data structure in hardware; this algorithm is slow due to GPU thread block size limitations and synchronization points, but demonstrates favorable time complexity. The second algorithm uses dynamic parallelism to remove synchronization and scales to utilize available GPU hardware (single GPU). We perform experiments on both synthetic and real world data sets. The presented results show improvement in execution time with respect to recent algorithms, and low memory usage compared to recent algorithms. We achieve speedups of up to 38.8 over the serial sweep line algorithm on real world data.

A Randomized Controlled Trial of Adding Deep Parasternal Intercostal Plane Block to Interpectoral-Pectoserratus Plane Block in Breast Cancer Surgery.

The interpectoral-pectoserratus plane block is expected to anesthetize the lateral breast, but it is unclear whether the deep parasternal intercostal plane block may enhance recovery by providing analgesia to the medial breast. Patients undergoing breast cancer surgery were randomly assigned to receive either the interpectoral-pectoserratus block (single block) or interpectoral-pectoserratus combined with deep parasternal intercostal block (combined block). The primary outcome was the quality of recovery-15 questionnaire score assessed at 24 hours postoperatively. Secondary measures included dermatomal block assessment, pain severity, opioid consumption, opioid-related adverse events, hospital length of stay, and chronic postsurgical pain at 3 months after surgery. One hundred and sixteen patients were recruited, 58 in the single block group and 58 in the combined block group. There was no important difference in the 24-hour quality of recovery scores with mean (standard deviation [SD]) 123.6 (6.3) in the single block group and 123.2 (7.1) in the combined block group (mean difference, 0.4; 95% confidence interval [CI], -2.0 to 2.9; P =.731). There was greater dermatomal block on medial breast in the combined block group. There were no differences in other secondary outcomes. Addition of deep parasternal intercostal plane block was not superior to interpectoral-pectoserratus plane block alone for the quality of recovery in patients undergoing breast cancer surgery.

Predictive alternating runs and random task-switching sequences produce dissociative switch costs in the Consonant-Vowel/Odd-Even task.

Task-switching is commonly used to investigate working memory and attentional control processes. The current study compares predictive versus non-predictive task-sequencing effects on task-switching performance. Participants completed four blocks of the Consonant-Vowel/Odd-Even (CVOE) task: Two single task pure blocks, a predictable switch block where task switching occurred every two trials, and a random switch block where switching was unpredictable. In addition to mean error rates and response times (RTs), we assessed sequence effects on local switch costs (i.e., switch vs. nonswitch trials) and global costs (i.e., nonswitch vs. pure trials) for both error rates and RTs along with their underlying distributions. Overall, we show that while predictive and random switching produced similar patterns for mean error rates and RTs, a dissociation occurred in RT switch costs. When switching was random, local costs were inflated. In contrast, predictive switching increased global costs. Increased local costs for random versus predictive switching reflect an increase in task-setreconfiguration processes as participants struggle to reconfigure to an unpredictable task type in working memory on a subsequent trial. Separately, increased global costs for predictive switching reflect declines in task-set maintenance processes, as participants must maintain both task types in working memory while simultaneously monitoring their progress through the trial sequencing.

Surgical Treatment of Primary Spinal Tumors

Primary spinal tumors appear to be much less common than metastatic lesions, but their surgical treatment comprises a complex and multifaceted task. Numerous factors influence indications and timing of surgical intervention, including neurological status of the patient, histological characteristics of the tumor, its localization, stability of the spinal column, and comorbidities. Significant spinal cord compression, rapid progression of neurologic deficits, or pronounced instability of the spinal column may require urgent surgical intervention. When the spinal canal is not affected, treatment should start with a biopsy to accurately determine the histology of the tumor. Some tumor types, such as giant cell tumors, osteoblastomas, chordomas, and chondrosarcomas, require complete removal of the tumor. However, performing a wide resection in a single block is often found difficult due to compression of vascular and nerve structures. Current approaches to surgical management of primary spinal tumors involve minimally invasive techniques that significantly improve postoperative recovery and reduce the risk of complications. These techniques were originally used to treat degenerative spinal diseases and trauma; however, they have also demonstrated their effectiveness in tumor surgery. Adapting surgical strategy based on histology and tumor location, as well as integrating minimally invasive techniques, can improve patient survival and quality of life. The present paper describes the latest advances in the surgical treatment of primary spinal tumors, discusses current techniques and strategies, and prospects for further research in this area.

Grounded Meminductor Emulator using a Single Active Building Block and Its Application

Grounded Meminductor Emulator using a Single Active Building Block and Its Application

Study on tensile behavior at various temperatures of the Mg-7Gd-5Y-1Nd-2Zn-0.5Zr alloy

Mg-rare earth (RE)-Zn alloys with long-period stacking ordered (LPSO) structure show excellent room temperature, elevated temperature mechanical properties. In this work, microstructure and mechanical properties of Mg-7Gd-5Y-1Nd-2Zn-0.5Zr (wt%) alloy after tensile deformation at various temperatures (room temperature (RT), 250 °C and 300 °C) were investigated. The pre-precipitated alloy exhibited tensile yield strength (TYS) of 149 MPa at room temperature, while it maintained relatively high TYS at 250 °C (154 MPa) and 300 ℃ (123 MPa). The microstructural characterizations revealed that such outstanding heat resistance is mainly attributed to the blocky LPSO structure near the grain boundary; basal plate-like precipitates, twins and kink bands inside the grain. The blocky LPSO structure exhibits a coherent boundary with one α-Mg grain, while being incoherent with other α-Mg grains or the LPSO structure. Cracks primarily occured along the incoherent interface. Basal plate-like precipitates formed during elevated temperature tensile deformation included GP zones, γ', metastable LPSO building blocks, and fine 14H-LPSO structure. A probable γ-precipitation sequence is supersaturated solid solution → GP zones (ABAB-type) → single LPSO building block (γ')→ various metastable LPSO building block clusters→ 14H-LPSO (γ). The deformation modes (sliding, twinning, kinking, grain boundary sliding, etc) modified with the tensile temperature increase. <c+a> dislocations were observed at elevated temperatures. As the temperature of tensile test increases, twins become less. Grain boundary sliding occurs at elevated temperatures.

A Deep Learning-based Approach for Channel Estimation in Multi-access Multi-antenna Systems

This paper studies estimating the channel state information at the end of receiver (CSIR) for multiple transmitters communicating with only one receiver so that the latter can decode the incoming signal more efficiently. The transmitters and the receiver are all equipped with multi-antennas and using orthogonal space-time block codes (OSTBC). An algorithm is developed based on deep learning for estimating multi-user multiple-input multiple-output (MU-MIMO) channels. The algorithm could estimate the CSIR using a single pilot block. The proposed convolutional neural network (CNN) architecture designed for this task begins with an input layer that accepts grayscale images, followed by six convolutional blocks for feature extraction and processing. The network concludes with a fully connected layer to output the estimated channel information. It is trained using a regression loss function to map input images to accurate channel information accurately. The performance of the proposed method is compared with classical methods like least square and subspace-based methods, including Capon and rank revealing QR (RRQR) methods. CNN achieved better performance in comparison with the reference. Computer simulations are included to validate the proposed method.

IPACK Block and Adductor Canal Catheter vs Adductor Canal Catheter for Total Knee Arthroplasty: A Randomized Controlled Trial

Background: Regional anesthetic techniques including the adductor canal catheter (ACC) have aided management of post-operative pain for total knee arthroplasty (TKA). The interspace between the popliteal artery and posterior capsule of the knee (iPACK), has been introduced to address posterior knee pain that is not well covered by the ACC. Studies have looked at the addition of the iPACK block to subjects who received an ACC with and without periarticular local infiltration with varying results. We hypothesized that adding the iPACK block to subjects who also received an ACC and periarticular injection (PAI) would significantly decrease opioid consumption compared to the ACC alone in TKA. Methods: Sixty subjects were randomized to receive an ACC alone (control group) or ACC plus single shot iPACK block (iPACK group) for TKA. All subjects were operated on by the same surgeon and received the same PAI. For the primary outcome of postoperative pain, we used opioid consumption as measured by morphine milligram equivalent (MME). Secondary outcomes included pain scores determined by the visual analog scale (VAS), distance ambulated, time to physical therapy (PT) and length of hospital stay. Results: We did not observe a significant difference between groups for opioid consumption, pain scores, distance ambulated (p &gt; 0.05 across all time points), length of hospital stay (p = 0.64), or time to PT (p = 0.32). Conclusion: When combined with an ACC and PAI, the iPACK block did not significantly decrease opioid consumption, pain scores, time to first PT session or increase distance ambulated.

Age and Sex Structure of the Population of the Potapovo and Sintashta Cultures in the Late Bronze Age Based on the Materials of Funerary Monuments from the Volga-Ural Region

The paper analyzes the gender and age structure of the population of the Potapovo and Sintashta cultures in the late Bronze Age based on anthropological materials from a cemetery in the Volga-Ural region. According to archaeological data, both of them belong to a single cultural block; nevertheless, issues of their correlation and primacy in the time of origin are still debatable. 336 markers of gender and age definition in the individuals were applied. Calculations of the main demographic indicators were carried out; histograms of the ratio of age and gender groups were constructed for each culture under consideration. Using the principal components method, an intergroup comparison was carried out on demographic indicators of 31 series in the south of Eastern Europe and Transcaucasia. The indicators of the Potapovo and Sintashta groups have high infant mortality. At the same time, more even ratios of sex and age classes were noted for the Sintashta group of the Trans-Urals. In contrast to Potapovo, a more favorable external and internal social situation for the Sintashta population is assumed. A comparison of demographic indicators against a broader geographical and chronological background demonstrates, firstly, the convergence of the Potapovo and Sintashta groups, the manifestation of similar trends among subsequent series of log culture in the same region, and, on the contrary, sharp differences with the data of the previous pastoral Yamno-Poltavka population. Thus, the demographic indicators of the Potapovo and Sintashta cultures can symbolize the transition to new ethno-cultural living conditions, to the beginning of the formation of stationary geographical points, to the gradual settling of collectives.

Evaluating Effects of Continuous Occlusion on Visual Letter Identification

Visual letter identification refers to humans’ use of a visual system to recognize the 26 letters in the English alphabet. Letters may be partially occluded by nonadjacent small occlusion blocks (called discrete occlusion) or a single occlusion block (called continuous occlusion) in the real world, thereby affecting visual letter identification. The effects caused by discrete occlusion have been investigated in existing research. The results indicate that humans possess the ability to identify partially occluded letters and a large occlusion ratio results in low identification accuracy. However, few studies have explored the effects caused by continuous occlusion and revealed precise reflections on occlusion effects. This study presents an evaluation to explore the effects of continuous occlusion on visual letter identification. A controlled experiment is designed to achieve two research goals: identifying the maximum extent of occlusion ratio (named upper bound) that does not affect visual letter identification and investigating the change patterns of the accuracy of occluded letter identification with the gradual increase in occlusion ratio. The experimental results are analyzed in detail, and three main findings are obtained. First, moderately occluded letters can be accurately identified in a continuous occlusion scene. Second, the precise upper bounds are obtained for each of the 26 letters. Lastly, the change patterns for the 26 letters present three nonlinear decline patterns. The findings could inspire technical advancements in the fields of visualization, computer vision, and healthcare.

Lasting effects of transcranial direct current stimulation on the inducibility of synaptic plasticity by paired-associative stimulation in humans

BackgroundTranscranial direct current stimulation (tDCS) is capable of eliciting changes in cortical neuroplasticity. Increasing duration or repetition of tDCS during the after-effects of a first stimulation has been hypothesized to enhance efficacy. Computational models suggest sequential stimulation patterns with changing polarities to further enhance effects. Lasting tDCS effects on neural plasticity are of great importance for clinical applications.ObjectiveThe study systematically examined the influence of different tDCS paradigms on long term potentiation (LTP)-like plasticity in humans, focusing on stimulation duration, repetition frequency and sequential combinations of changing polarities as the underlying characteristics.MethodsAmplitude changes of motor evoked potentials (MEP) were measured in response to paired associative stimulation (PAS) 6 h after application of different tDCS protocols. In total, 36 healthy participants completed the study, randomised into three groups with different stimulation protocols (N = 12 each).ResultstDCS was able to display lasting modulatory effects on the inducibility of LTP-like plasticity in the human motor cortex 6 h after stimulation. TDCS with the anode on primary motor cortex significantly increased MEP amplitudes following PAS induction. Further analyses highlighted single stimulation block duration to be of higher importance than repetitive protocols for efficacy of effects.ConclusionstDCS is capable of inducing lasting changes in the brain’s capability to interact with future stimuli. Especially, effects on the inducibility of LTP-like plasticity might only be detectable with specific tests such as PAS and might otherwise be overlooked. Refined tDCS protocols should focus on higher current and duration of single stimulations instead of implementing complex repetitive schedules.

An efficient detector for detecting surface defects on cold-rolled steel strips

Surface-defect inspection is vital in cold-rolled steel-strip manufacturing, given the complexities of production environments and the high speeds involved. Further, the defects on cold-rolled steel strips are often characterized by their small size, diversity of types, and similarities among different types, posing significant challenges in balancing detection accuracy and efficiency. To address the challenges, we designed a detector based on You Only Look Once version 5 (YOLOv5) to achieve precise detection of surface defects on cold-rolled steel strips. First, a dataset containing seven types of defects was curated, named the Cold-Rolled Steel Defect Dataset (CR7-DET). Next, a feature-extraction network based on residual-like connections within a single residual block (Res2net) was developed to enhance the model’s feature-extraction capability, alongside introducing a multi-head attention module to focus on key information features. To reduce the information loss during feature fusion, we established an adaptive feature-fusion Path Aggregation Network (aff-PAN), which was optimized by designing a lightweight adaptive down-sampling module (LAD) to increase the sensory-field implementation of feature fusion. The ghost convolution effectively reduced the number of parameters and increased the speed without affecting the model’s performance. Finally, experiments were conducted on our CR7-DET and a public dataset (GC10-DET). With a reduced parameter count of 6.85 million, our model achieved a mean average precision(mAP) of 87.6% on CR7-DET and 79.7% on GC10-DET. The experimental results demonstrated that our model achieved a balance between detection accuracy and inference efficiency. The model has the potential to reduce scrap rates caused by defects and improve the overall surface quality of cold-rolled steel strips.

Progress Toward Poliomyelitis Eradication - Pakistan, January 2023-June 2024.

Since its launch in 1988, the Global Polio Eradication Initiative has made substantial progress toward the eradication of wild poliovirus (WPV), including eradicating two of the three serotypes, and reducing the countries with ongoing endemic transmission of WPV type 1 (WPV1) to just Afghanistan and Pakistan. Both countries are considered a single epidemiologic block. Despite the occurrence of only a single confirmed WPV1 case during the first half of 2023, Pakistan experienced widespread circulation of WPV1 over the subsequent 12 months, specifically in the historical reservoirs of the cities of Karachi, Peshawar, and Quetta. As of June 30, 2024, eight WPV1 cases had been reported in Pakistan in 2024, compared with six reported during all of 2023. These cases, along with more than 300 WPV1-positive environmental surveillance (sewage) samples reported during 2023-2024, indicate that Pakistan is not on track to interrupt WPV1 transmission. The country's complex sociopolitical and security environment continues to pose formidable challenges to poliovirus elimination. To interrupt WPV1 transmission, sustained political commitment to polio eradication, including increased accountability at all levels, would be vital for the polio program. Efforts to systematically track and vaccinate children who are continually missed during polio vaccination activities should be enhanced by better addressing operational issues and the underlying reasons for community resistance to vaccination and vaccine hesitancy.

Familial severe skeletal Class II malocclusion with gingival hyperplasia caused by a complex structural rearrangement at the KCNJ2-KCNJ16 locus

The aim of this work was to identify the underlying genetic cause in a four-generation family segregating an unusual phenotype comprising a severe form of skeletal Class II malocclusion with gingival hyperplasia. SNP-array identified a copy number gain on chr1, however this chromosomal region did not segregate correctly in the extended family. Exome sequencing also failed to identify a candidate causative variant, but highlighted co-segregating genetic markers on chr17 and chr19. Short- and long-read genome sequencing allowed us to pinpoint and characterize at nucleotide-level resolution a chromothripsis-like complex rearrangement (CR) inserted into the chr17 co-segregating region at the KCNJ2-SOX9 locus. The CR involved the gain of five different regions from chr1 that are shuffled, chained and inserted as a single block (∼828 kb) at chr17q24.3. The inserted sequences contain craniofacial enhancers that are predicted to interact with KCNJ2/KCNJ16 through neo-topologically associating domain (TAD) formation to induce ectopic activation. Our findings suggest that the CR inserted at chr17q24.3 is the cause of the severe skeletal Class II malocclusion with gingival hyperplasia in this family and expands the panoply of phenotypes linked to variation at the KCNJ2-SOX9 locus. In addition, we highlight a previously overlooked potential role for misregulation of the KCNJ2/KCNJ16 genes in the pathomechanism of gingival hyperplasia associated with deletions and other rearrangements of the 17q24.2-q24.3 region (MIM 135400).

Development of an articulated concrete armor unit against high waves and uneven slopes

In this study, a new articulated concrete armor unit named Couple-Lock, which can be enlarged in size to cope with high waves, is easy to secure binding force between units, and can be applied to various field conditions, was developed. The Couple-Lock consists of two symmetrical blocks. One symmetrical block has four legs installed in all directions on one end of the body. Since two left-right symmetrical blocks are connected with a wire rope and behave, a pair of blocks can be treated as a single block and enabling large size to cope with high waves. Also, the Couple-Lock responds flexibly to topographical changes. In order to examine the hydraulic performance and stability of the developed armor unit, a hydraulic model experiment was conducted. As a result, the average reflection coefficients of ordinary wave and storm wave conditions were calculated as 0.433 and 0.533, respectively. The average transmission coefficients under ordinary wave and storm wave conditions were calculated as 0.046 and 0.147, respectively. Among the 62 storm wave conditions, wave overtopping occurred in 50 storm waves. The stability factor of the Couple-Lock was calculated to be about 18, which is twice of the stability factor of the tetrapod.

Scattered storage for retail e-commerce fulfillment warehouses with consideration for product turnover

Storage assignment policy of a warehouse controls how the stocks are assigned to various storage locations. Traditionally used storage policies, such as dedicated or random storage, do not address the specific needs of retail e-commerce fulfillment warehouses that store a wide assortment of products and service a large number of single-unit orders under strict timelines. This has led to the development of scattered storage assignment policy, which deliberately spreads the stocks of every product across the warehouse. However, the available approaches towards scattering have largely ignored product turnover, which is a significant determinant of order picking travel. To fill this research gap, we propose a new, turnover-incorporated scattered storage policy. More specifically, we develop a new measure of scattering of stocks and a mathematical model that optimizes the measure by scattering the stocks across the warehouse, while considering product turnover. Certain important properties of this measure are proved and eventually exploited in developing a heuristic approach to solve the proposed mathematical model for large problem instances. An upper bound for the objective function of the mathematical model is used as a benchmark to evaluate the performance and computation time of the proposed heuristic, as well as solutions obtained through genetic algorithms and surrogate optimization. We conduct a simulation study using the proposed heuristic to analyze the impact of the scattering of stocks on order picking performance in a single block, low level, picker-to-parts warehouse. We also present the impact of warehouse operating parameters on the performance of the proposed scattered storage policy.

Spatial organisation of the soil macrofauna community of an oak forest in the steppe zone of Ukraine

Background. Environmental impact assessments and the development of measures for the protection and sustainable use of ecosystems should take into account that not only steppe ecosystems but also forest, marsh, salt marsh and meadow ecosystems are referenced for the steppe zone. A comparative approach requires the study of reference ecosystems to understand how much a particular ecosystem has been transformed or how far it is from natural patterns in the restoration process. The soil macrofaunal community of the forest ecosystem of the right bank of the Samara River can be considered a reference for many forest ecosystems in the region. The aim of this study was to identify patterns of spatial organization of the soil macrofaunal community of an oak forest on the right bank of the Samara River. Materials and Methods. A study was conducted in a deciduous woodland located in an oak forest on the right bank of the Samara River. The study area was divided into 5 transects, each consisting of 20 sampling points with a 2 m distance between rows. The samples of the soil macrofauna were taken from a single block of soil that was 25×25×30 cm deep and removed quickly. Vascular plant species lists were recorded for each 2×2 m subplot. The soil penetration resistance and electrical conductivity were measured. Soil faunal trophic activity was assessed by means of a bait lamina test. Results and Discussion. The spatial structure of the community is complex in terms of hierarchy. The driver of the broad-scale component of spatial variation in the community is the properties of the topsoil, mainly the density of the litter. Vegetation cover forms a broad component of the spatial variation in soil macrofauna. An important factor in structuring ecological space is the location of trees. The pure spatial pattern is represented by broad-, medium-, and fine-scale components. Conclusion. The soil macrofaunal community of an oak forest on the slope of the right bank of a steppe river has a high level of abundance and taxonomic and ecological diversity. The spatial distribution of trees forms a broad-scale component of variation in the soil macrofaunal community, and herbaceous cover forms a medium-scale component. The fine-scale component of community variation is due to neutral factors.