Water hammer protection for diversion systems in front of pumps in long-distance water supply projects

For a water supply system with long-distance diversion pipelines, in addition to the water hammer problems that occur beyond pumps, the safety of the water diversion pipeline in front of pumps also deserves attention. In this study, a water hammer protection scheme combined with an overflow surge tank and a regulating valve was developed. A mathematical model of the overflow surge tank was developed, and an analytical formula for the height of the overflow surge tank was derived. Furthermore, a practical water supply project was used to evaluate the feasibility of the combined protection scheme and analyze the sensitivity of valve regulation rules. The results showed that the combined protection scheme effectively reduced the height of the surge tank, lessened the difficulties related to construction, and reduced the necessary financial investment for the project. The two-stage closing rule articulated as fast first and then slow could minimize the overflow volume of the surge tank when the power failure occurred, while the two-stage opening rule articulated as slow first and then fast could be more conducive to the safety of the water supply system when the pump started up.

SCALE OPTIMIZATION FOR DISTORTED MODEL ON DIVERSION SYSTEM OF HYDROPOWER STATION

Long diversion system of hydropower station, including surge tank, inlet tunnel and penstock, is an inseparable whole system. Scale effects of distorted model on the diversion system are studied in the present paper. Based on the concept of model scale correlation and the method of parameter expression of model scale, the model scale optimization can be realized. Furthermore, a quantitative criterion for the choice of distorted model or normal model is presented. The study shows that distorted model can simultaneously satisfy the similarity conditions derived from surge wave equations, water hammer equations and wave speed equation for the diversion system. In addition, an example for the design of a practical distorted model is provided.

Performance of a prehospital trauma diversion system in Hong Kong, China

Purpose： To evaluate the performance of a prehospital trauma diversion system in Hong Kong, China. Methods： A retrospective analysis of prospectively collected data in the trauma registry of Queen Mary Hospital, Hong Kong from I January 2009 to 31 December 2013 was done. All adult patients aged 18 years or above, either primarily or secondarily diverted to Queen Mary Hospital according to the trauma patient diversion protocol, were recruited. Need for trauma center level of care was based on a consensus-based criterion standard published in 2014. Performance of the protocol in terms of over-diversion and under-diversion was determined. Results： A total of 209 patients were included for analysis. About 30% of the patients required trauma center level of care. The most common reason was the need for vascular, neurologic, abdominal, thoracic, pelvic, spine or limb-conserving surgery within 24 h of presentation. The over-diversion rate and under-diversion rate were 69.6% and 19.7% respectively. Conclusion： The trauma patient diversion protocol currently in use in Hong Kong is not accurate enough. Further revision and refinement is needed.

The mechanisms of thermal solidification agent promoting steam diversion in heavy oil reservoirs

At high cycles of steam huff&puff,oil distribution in reservoirs becomes stronger heterogeneity due to steam channeling.Thermal solidification agent can be used to solve this problem.Its solution is a lowviscosity liquid at normal temperature,but it can be solidified above 80℃.The plugging degree is up to 99%at 250℃.The sweep efficiency reaches 59.2%,which is 7.3%higher than pure steam injection.In addition,simultaneous injection of viscosity reducer and/or nitrogen foams can further enhance oil recovery.The mechanism of this technology depends on its strong plugging ability,which changes the flowing pattern of steam to effectively mobilize remaining oil.Viscosity reducer and nitrogen foams further expand the sweep range and extends the effective period.Therefore,thermal solidification agent can plug steam channeling paths and adjust steam flowing direction to significantly enhance oil recovery at high cycles of steam huff&puff.

Fracture propagation law of temporary plugging and diversion fracturing in shale reservoirs under completion experiments of horizontal well with multi-cluster sand jetting perforation

This study conducted temporary plugging and diversion fracturing(TPDF)experiments using a true triaxial fracturing simulation system within a laboratory setting that replicated a lab-based horizontal well completion with multi-cluster sand jetting perforation.The effects of temporary plugging agent(TPA)particle size,TPA concentration,single-cluster perforation number and cluster number on plugging pressure,multi-fracture diversion pattern and distribution of TPAs were investigated.A combination of TPAs with small particle sizes within the fracture and large particle sizes within the segment is conducive to increasing the plugging pressure and promoting the diversion of multi-fractures.The addition of fibers can quickly achieve ultra-high pressure,but it may lead to longitudinal fractures extending along the wellbore.The temporary plugging peak pressure increases with an increase in the concentration of the TPA,reaching a peak at a certain concentration,and further increases do not significantly improve the temporary plugging peak pressure.The breaking pressure and temporary plugging peak pressure show a decreasing trend with an increase in single-cluster perforation number.A lower number of single-cluster perforations is beneficial for increasing the breaking pressure and temporary plugging peak pressure,and it has a more significant control on the propagation of multi-cluster fractures.A lower number of clusters is not conducive to increasing the total number and complexity of artificial fractures,while a higher number of clusters makes it difficult to achieve effective plugging.The TPAs within the fracture is mainly concentrated in the complex fracture areas,especially at the intersections of fractures.Meanwhile,the TPAs within the segment are primarily distributed near the perforation cluster apertures which initiated complex fractures.

How elevation and soil properties affect plant distribution patterns and species diversity in the Mediterranean mountain ecosystem of Al-Jabal Al- Akhdar, Libya

The objectives of this study were to assess distribution patterns of plant species richness,plant diversity and vegetation structure in relation to environmental factors along elevation gradient in Al-Jabal Al-Akhdar,Libya.For each species,its growth form,chorological affinities,degree of occurrence,endemism status and originality were provided.A total of 534 taxa were generated from 70 families of the flowering plants,and 3 of the non-flowering plants were identified.The native flora of the study area was counted for 80.2%of the total indigenous taxa(465).The hump-shaped pattern of plant species richness was obtained,with the highest species richness at the mid-elevations,and both ends of the gradient have the lowest.The annuals(300 species,56.2%)and non-succulent perennial herbs(165 species,30.9%)were the most dominant growth forms of the total species composition.Along the elevation gradient,Asteraceae,Fabaceae,Poaceae,Lamiaceae and Apiaceae were the dominant families with the highest numbers of species.This investigation recorded 31 endemic taxa,comprising 25 dicots and 6 monocots,primarily of Mediterranean origin,with most belonging to the Asteraceae and Lamiaceae families.Mediterranean chorotype was the dominant,whether pure(mono-),or combined with one(bi-and pluri-regional)or more(pluri-regional).Application of cluster analysis on the vegetation data yielded four cluster groups;each was linked to an elevation level.It emphasized the importance of establishing conservation strategies to minimize human disturbance and safeguard relic habitats of Juniperus phoenicea L.at its southern distribution limits in Africa,underlining the proactive management required for species preservation.The application of Redundancy Analysis revealed that Shannon diversity index(H'),pH and Fe were the determinant soil factor in the mid-elevation levels(L2 and L3)whereas altitude,fine sand,HCO3,OM,and soil contents of Na,SO4 and Cl for the extreme levels(L1 and L4).

Latitudinal gradients of biodiversity and ecosystem services in protected and non-protected oak forest areas can inform climate smart conservation

Adaptive governance of areas set aside for future protection of biodiversity,sustainable production,and recreation requires knowledge about whether and how effects of area protection are modulated by climate change and redistribution of species.To investigate this,we compare biodiversity of plants(assessed using vegetation plots)and arthropods(collected with Malaise traps,analyzed using metabarcoding)and productivity(tree growth,determined using dendrochronology)in protected and non-protected oak(Quercus spp.)forests along a latitudinal gradient(55.6°N–60.8°N)in Sweden.We also compare historical,recent and projected future climate in the region.In contrast to established global latitudinal diversity gradients,species richness of plants and arthropods increased northwards,possibly reflecting recent climate-induced community redistributions,but neither was higher in protected than in non-protected areas,nor associated with contemporary ground temperature.Species composition of arthropods also did not differ between protected and non-protected areas.Arthropod biomass increased with latitude,suggesting that the magnitude of cascading effects mediated via their roles as pollinators,herbivores,and prey for other trophic levels,varies geographically and will change with a moving climate.Annual growth rate of oaks(an ecosystem service in the form of biomass increase and carbon sequestration)was independent of latitude and did not differ between protected and non-protected areas.Our findings question the efficacy of contemporary designation and management of protected oak forests,and emphasize that development and implementation of modified climate smart conservation strategies is needed to safeguard ecosystem functioning,biodiversity,and recreational values of protected forest areas against future challenges.

Elevational patterns of warming effects on plant community and topsoil properties: focus on subalpine meadows ecosystem

Climate warming profoundly affects plant biodiversity, community productivity, and soil properties in alpine and subalpine grassland ecosystems. However, these effects are poorly understood across elevational gradients in subalpine meadow ecosystems. To reveal the elevational patterns of warming effects on plant biodiversity, community structure, productivity, and soil properties, we conducted a warming experiment using open-top chambers from August 2019 to August 2022 at high(2764 m a. s. l.), medium(2631 m a. s. l.), and low(2544 m a. s. l.) elevational gradients on a subalpine meadow slope of Mount Wutai, Northern China. Our results showed that three years of warming significantly increased topsoil temperature but significantly decreased topsoil moisture at all elevations(P<0.05), and the percentage of increasing temperature and decreasing moisture both gradually raised with elevation lifting. Warming-induced decreasing proportions of soil organic carbon(SOC, by 19.24%), and total nitrogen(TN, by 24.56%) were the greatest at high elevational gradients. Experimental warming did not affect topsoil C: N, p H, NO_(3)^(-)-N, or NH_(4)^(+)-N at the three elevational gradients. Warming significantly increased species richness(P<0.01) and Shannon-Weiner index(P<0.05) at low elevational gradients but significantly decreased belowground biomass(P<0.05) at a depth of 0–10 cm at three elevational gradients. Warming caused significant increases in the aboveground biomass in the three elevational plots. Warming significantly increased the aboveground biomass of graminoids in medium(by 92.47%) and low(by 98.25%) elevational gradients, that of sedges in high(by 72.44%) and medium(by 57.16%) elevational plots, and that of forbs in high(by 75.88%), medium(by 34.38%), and low(by 74.95%) elevational plots. Species richness had significant linear correlations with SOC, TN, and C: N(P<0.05), but significant nonlinear responses to soil temperature and soil moisture in the warmed treatment(P<0.05). The warmed aboveground biomass had a significant nonlinear response to soil temperature and significant linear responses to soil moisture(P<0.05). This study provided evidence that altitude is a factor in sensitivity to climate warming, and these different parameters(e.g., plant species richness, Shannon-Weiner index, soil temperature, soil moisture, SOC, and TN) can be used to measure this sensitivity.

The Influence of Plant Diversity and Functional Composition on Ecosystem Stability of Four Stipa Communities in the Inner Mongolia Plateau

The main purpose of this study was to examine the effects of plant species diversity and functional composition (the identity of the plant functional groups) on ecosystem stability of Stipa, communities in the Inner Mongolia Plateau. The research work was based on a 12-year study (from 1984 to 1995) of species abundance, diversity, and primary productivity of four Stipa communities, i.e. S. baicalensis Roshev., S. grandis P. Smirn., S, krylovii Roshev., and S. klemenzii Roshev. respectively. The Shnnon-Wiener index was used as a measurement of plant diversity, while functional composition was used to differentiate the functional groups that were included in the communities. The plant species of four Stipa communities were classified into functional groups based on the differences in life forms and ecological groups, which influence their performance in resource requirements, seasonality of growth, tolerance to water stress, and life history. Plant species were classified into five functional groups based on their differences in life form, shrubs and half shrubs, perennial bunch grasses, perennial rhizome grasses, forbs, annuals and biennials. Based on their differences in water requirement these species were classified into four functional groups: xerads, intermediate xerads, intermediate mesophytes, and mesophytes. The results showed: 1) Plant species diversity stabilized ecosystem processes. Shannon-Wiener index were 2.401 4, 2.172 0, 1.624 8, 0.354 3 from S. baicalensis community to S. grandis, S. krylovii and S. klemenzii community, respectively. The dynamics of the aboveground net primary productivity (ANPP) for a 12-year's period showed a reverse pattern, the coefficients of variation of the four communities were 21.94%, 20.63%, 29.21% and 39.72% respectively. 2) The Life form functional group component of diversity was a greater determinant of the ecosystem processes than the species component of diversity. The effects of perennial bunch grasses, perennial rhizome grasses and forbs on community stability were highly significant. 3) The ecological group component of diversity was also a great determinant of the ecosystem processes. The effects of xerads, intermediate xerads, and mesophytes on community stability were also very strong.

Metabolic Characteristics and Functional Diversity of Carbon Source in Microflora of Ponds with Recirculating Aquaculture System

With Biolog Eco microplate, metabolic characteristics and functional diver-sity of carbon source in microflora of ponds were researched based on recitculating ponds and control ponds in order to explore effects of eco-adjustments on microflo-ra in ponds. The results indicate that total number of bacterium, microbial metabolism activity, and diversity index in P7, P8, P1 and P2 kept higher, fol owed by P3, P4, P5 and P6. The utilization rate of microbes on sugars achieved the highest （31.0%-48.7%）, fol owed by carboxylic acid （13.4%-18.0%）, amino acid （10.1%-20.5%）, polymers （9.4%-17.0%）, biopolymer （5.7%-9.7%） and phenol （4.95%-7.50%）. Principal component analysis divided microflora in different ponds, suggesting that microbial community has varied carbon source characteristics and nitrogen-containing compound and biopolymer metabolisms are most affected.

Construction of AFLP Molecular Marking System in Mangifera indica L.

[Objective ] The study aimed to construct the AFLP molecular marking system in Mangifera indica. [ Method ] Four varieties of Mangifera indica were used to explore new ways for high-quality DNA, and AFLP analysis of 31 varieties of Mangifera indica was carried out to detect the varietal genetic diversity. [ Result] 14 pairs of primers with stronger polymorphism, better banding patterns and higher resolution were screened out from 64 pairs of selective amplification primers. Then they were used to analyse the fingerprint of 31 varieties of Mangifera indica, the results showed that the ratio of polymorphic bands amplificated by the 14 pairs of primers reached 97% in 31 varieties of Mangifera.[ Conclusion] It was suggested that AFLP was suitable for detecting the polymorphism of Mangifera indica resources.

Comparative Study on Genetic Diversity of Beauveria bassiana in Different Forest Ecosystems

ISSR molecular marker technology was adopted to conduct comparison analysis on genetic diversity level and population genetic structure of Beauveria bassiana population in natural secondary forest （Langyashan national forest park） in Chuzhou City of Anhui Province and artificial pure pine forest （Magushan forest farm） in Xuancheng City of Anhui Province.Seven primers were selected to conduct PCR amplification on total 222 strains of B.bassiana in two populations,a total of 58 unique amplified loci were obtained through amplification,the number of polymorphic loci was 56,the percentage of polymorphic loci was 96.55%,Nei＇s genetic diversity was 0.299 3,Shannon information index was 0.459 3,genetic differentiation coefficient among populations （Gst） was 0.128 3,gene flow Nm=3.398 4;the gene flow between the two populations was small,genetic differentiation was relatively large,being 12.83%,this may be caused by human selective pressures and barrier of gene flow;the genetic variation level of B.bassiana populations in Langyashan was relatively high（PPL=96.55%,H=0.278 1,I= 0.429 9）;the genetic variation level of B.bassiana populations in Magushan was relatively low（PPL=93.10%,H=0.255 2,I= 0.382 5）.The genetic diversity of B.bassiana from the primary forest in Dabieshan was studied（PPL=81.00%,H=0.318 7,I= 0.478 2）,indicating that the genetic diversity of B.bassiana populations in Dabieshan with complex ecological environment was the highest,followed by the populations in natural secondary forest,and the genetic diversity in artificial pure pine forest was the lowest.Nei＇s genetic distance was adopted to construct the genetic relationship dendrogram of B.bassiana individuals collected from Langyashan and Magushan,from the cluster analysis of UPGMA,the strains from the same collection places clustered together.

Single-cell and spatial omics:exploring hypothalamic heterogeneity

Elucidating the complex dynamic cellular organization in the hypothalamus is critical for understanding its role in coordinating fundamental body functions. Over the past decade, single-cell and spatial omics technologies have significantly evolved, overcoming initial technical challenges in capturing and analyzing individual cells. These high-throughput omics technologies now offer a remarkable opportunity to comprehend the complex spatiotemporal patterns of transcriptional diversity and cell-type characteristics across the entire hypothalamus. Current single-cell and single-nucleus RNA sequencing methods comprehensively quantify gene expression by exploring distinct phenotypes across various subregions of the hypothalamus. However, single-cell/single-nucleus RNA sequencing requires isolating the cell/nuclei from the tissue, potentially resulting in the loss of spatial information concerning neuronal networks. Spatial transcriptomics methods, by bypassing the cell dissociation, can elucidate the intricate spatial organization of neural networks through their imaging and sequencing technologies. In this review, we highlight the applicative value of single-cell and spatial transcriptomics in exploring the complex molecular-genetic diversity of hypothalamic cell types, driven by recent high-throughput achievements.

Adaptive channel estimation based on pilot signals and transform-domain processing in SISO/MIMO OFDM systems

Based on the transform-domain characteristics of pilot signals,a band suppression filter is used as a transform-domain filter to restrain the interference of noise in channel estimation.The performance effect on channel estimation for an orthogonal frequency division multiplex （OFDM） system by different energy coefficients in the transform domain and the energy coefficient under the different signal-to-noise ratios （SNR） are also analyzed.A new energy coefficient expression is deduced.It is theoretically proven that dynamically selecting an energy coefficient can significantly improve the performance of channel estimation.Simulation results show that the proposed algorithm can achieve better performance close to the theoretic bounds of perfect channel estimation. The algorithm is adapted to single-input single-output （SISO） OFDM and multi-input multi-output （MIMO） OFDM systems.

Single-cell transcriptomic profiling reveals ZEB1-mediated regulation in microglial subtypes and the impact of exercise on neuroinflammatory responses

Background:This study aims to identify distinct cellular subtypes within brain tissue using single-cell transcriptomic analysis,focusing on specific biomarkers that differentiate cell types and the effects of traditional and exercise therapy.Methods:Four samples were analyzed:older control(OC),older exercise(OE),younger control(YC),and younger exercise(YE).Single-cell RNA sequencing was used to distinguish cellular subtypes through their biomarker profiles.Data visualization included violin and t-SNE plots to illustrate biomarker expression across cell clusters such as oligodendrocytes,microglia,and astrocytes.Additionally,BV2 cells were exposed to amyloid-beta fragments to simulate Alzheimer’s disease,assessing the impact of exercise-induced cellular responses.Results:Distinct cellular subtypes were identified:oligodendrocytes(MBP,St18),microglia(Dock8),and astrocytes(Aqp4,Gpc5).Sample OE was predominantly oligodendrocytes,while YE had more astrocytes,inhibitory neurons,and Canal-Retzius cells.YC showed a significant presence of Olfm3+ganglion neurons.ZEB1 gene knockout revealed changes in SMAD family gene expression,which regulate ferroptosis.Oxidative stress levels were also evaluated.Conclusion:This profiling enhances our understanding of brain cellular functions and interactions,potentially informing targeted therapies in neurological research.Exercise may influence brain cell immune responses and cell death pathways by regulating specific gene expressions,offering new insights for treating neuroinflammation and degeneration.

Performance analysis of space-time transmit diversity techniques for multi-antenna WCDMA systems

Several space-time coding based transmit diversity techniques for wideband code division multiple access (WCDMA) systems with four transmitter antennas are investigated. Performances of the rake receivers are analyzed and compared with those of the multi-antenna receive diversity techniques. Theoretical analysis shows that the multi-antenna transmit diversity techniques provide considerable performance gain at the mobile receiver in the wireless channel with less inherent multipath diversity, especially the G4 coding based scheme. Compared with the multi-antenna receive diversity techniques with the same diversity order, the transmit diversity techniques introduce much more multi-access plus multipath interference and require measures of interference suppression in the multi-user environments.

Relationship between diversion colitis and quality of life in rectal cancer

AIM:To investigated the incidence of diversion colitis(DC) and impact of DC symptoms on quality of life(QoL) after ileostomy reversal in rectal cancer.METHODS:We performed a prospective study with 30 patients who underwent low anterior resection and the creation of a temporary ileostomy for the rectal cancer between January 2008 and July 2009 at the Department of Surgery,Korea University Anam Hospital.The participants totally underwent two rounds of the examinations.At first examination,endoscopies,tissue biopsies,and questionnaire survey about the symptom were performed 3-4 mo after the ileostomy creations.At second examination,endoscopies,tissue biopsies,and questionnaire survey about the symptom and QoL were performed 5-6 mo after the ileostomy reversals.Clinicopathological data were based on the histopathological reports and clinical records of the patients.RESULTS:At the first examination,all of the patients presented with inflammation,which was mild in 15(50%) patients,moderate in 11(36.7%) and severe in 4(13.3%) by endoscopy and mild in 14(46.7%) and moderate in 16(53.3%) by histology.At the second examination,only 11(36.7%) and 17(56.7%) patients had mild inflammation by endoscopy and histology,respectively.There was no significant difference in DC grade between the endoscopic and the histological findings at first or second examination.The symptoms detected on the first and second questionnaires were mucous discharge in 12(40%) and 5(17%) patients,bloody discharge in 5(17%) and 3(10%) patients,abdominal pain in 4(13%) and 2(7%) patients and tenesmus in 9(30%) and 5(17%) patients,respectively.We found no correlation between the endoscopic or histological findings and the symptoms such as mucous discharge,bleeding,abdominal pain and tenesmus in both time points.Diarrhea was detected in 9 patients at the second examination;this number correlated with the severity of DC(0%,0%,66.7%,33.3% vs 0%,71.4%,23.8%,4.8%,P = 0.001) and the symptom-related QoL(r =-0.791,P < 0.001).CONCLUSION:The severity of DC is related to diarrhea after an ileostomy reversal and may adversely affect QoL.

Diversion colitis and pouchitis: A mini-review

Diversion colitis is characterized by inflammation of the mucosa in the defunctioned segment of the colon after colostomy or ileostomy. Similar to diversion colitis, diversion pouchitis is an inflammatory disorder occurring in the ileal pouch, resulting from the exclusion of the fecal stream and a subsequent lack of nutrients from luminal bacteria. Although the vast majority of patients with surgically-diverted gastrointestinal tracts remain asymptomatic, it has been reported that diversion colitis and pouchitis might occur in almost all patients with diversion. Surgical closure of the stoma, with reestablishment of gut continuity, is the only curative intervention available for patients with diversion disease. Pharmacologic treatments using short-chain fatty acids, mesalamine, or corticosteroids are reportedly effective for those who are not candidates for surgical reestablishment; however, there are no established assessment criteria for determining the severity of diversion colitis, and no management strategies to date. Therefore, in this mini-review, we summarize and review various recently-reported treatments for diversion disease. We are hopeful that the information summarized here will assist physicians who treat patients with diversion colitis and pouchitis, leading to better case management.

A numerical study on water diversion ratio of the Changjiang(Yangtze)estuary in dry season

We studied the flood, ebb and tidal averaged along (net) water diversion ratio (WDR) during dry season in the Changjiang (Yangtze) estuary, China, along with the effects of northerly wind, river discharge, tide and their interactions on WDR using the improved version of three-dimensional numerical model ECOM. Using data for annual mean wind speed and river discharge during January, we determined that the flood, ebb, net WDR values in the North Branch of the estuary were 3.48%, 1.68%,-4.06% during spring tide, and 4.82%, 2.34%,-2.79% during neap tide, respectively. Negative net WDR values denote the transport of water from the North Branch into the South Branch. Using the same data, the corresponding ratios were 50.09%, 50.92%, 54.97%, and 52.33%, 50.15%, 43.86% in the North Channel and 38.56%, 44.78%, 103.96%, and 36.92%, 43.17%, 60.97% in the North Passage, respectively. When northerly wind speed increased, landward Ekman transport was enhanced in the North Branch, increasing the flood WDR, while the ebb WDR declined and the net WDR exhibited a significant decrease. Similarly, in the North Channel, the flood WDR is increased, the ebb WDR reduced, and the net WDR showed a marked decrease. In the North Passage, the flood WDR also increased while the ebb and net WDR declined. As the river discharge increased, the flood and ebb WDR of the North Branch increased slightly and the net WDR increased markedly. In the North Channel the flood and ebb WDR changed very slightly, while the net WDR declined during spring tides and increased during neap tides. The WDR in the North Passage changed slightly during flood and ebb tides while the net WDR showed a marked increase. The WDR values of different bifurcations and the responses to northerly wind, river discharge, and tide are discussed in comparison with variations in river topography, horizontal wind-induced circulation, and tidal-induced residual current.

Diversity and Dynamics of Soil Free-Living Nematode Populations in a Mediterranean Agroecosystem

To determine the effect of agricultural management on the dynamics and functional diversity of soil nematode communities in a carrot field at Kibbutz Ramat Hakovesh, Israel, soil samples from 0-10 cm and 10-20 cm depths were collected during the growing season of carrot. Indices were used to compare and assess the response of soil free-living nernatode communities to agricultural management. Eighteen nematode families and 20 genera were observed during the growing period, with Cephalobus, Rhabditidae, Aphelenchus, Tylenchus, and Dorylaimus being the dominant genera/families. During the planting, mid-season and post-harvest periods the total number of nematodes at both depths was significantly lower (P < 0.01) in the carrot treatment than in the control plots, while during the harvest period at both depths total nematodes and bacterivores were significantly higher in the treatment plots (P < 0.01). The values of the maturity index (MI) at both depths were found to be significantly lower in the treatment plots than in the control plots during the pre-planting period (P < 0.05). Overall, WI, MI and PPI were found to be more sensitive indicators than other ecological indices for assessing the response of nematode communities to agricultural management in a Mediterranean agroecosystem