Types Of Bundles Research Articles

Exploring the ventricular morphology of the heart of Brycon amazonicus (Agassiz, 1829) (Teleostei, Characiformes).

Brycon amazonicus, a fish species widely distributed along freshwater rivers in Latin America, is important in maintaining ecological balance. Although some morphological/physiological aspects of B.amazonicus have been reported, the cardiac histomorphology of this species remains poorly understood. Therefore, this study aimed to describe the heart, emphasizing coronary distribution and ventricular myoarchitecture, correlating its structure with its functional activity. Ten adult specimens were anesthetized and perfused with Trident® ink to highlight the coronary branching. Subsequently, the animals were euthanized to collect the hearts, which were collected and processed for histological and histochemical techniques and scanning electron microscopy. We observed that the heart of B.amazonicus has a pyramidal ventricle, mixed myocardium, and coronary vessels restricted to the compact layer, according to classifications in the literature. The compact layer comprises two types of muscle bundles, arranged in longitudinal and circular orientations. The coronary circulation, which originates in the lateral cephalic region, starts from the heart and extends to the ventricular myocardium. Therefore, B.amazonicus has a cardiac morphology similar to that of other teleost species already described in the literature, expanding information on the Characiformes group. The description obtained of the heart of this species may contribute to further studies that seek a better understanding of the ecophysiology and evolution of teleost fish in the freshwaters of the Neotropical region.

Gating-spring stiffness increases outer-hair-cell bundle stiffness, damping, and receptor current

In our ears, outer-hair-cell bundles (OHBs) convert sound-induced forces into receptor currents that drive cochlear amplification, the process responsible for the micropascal-scale threshold and million-fold dynamic range of hearing. OHBs rely on gating springs to open mechanoelectrical-transduction (MET) ion channels, through which the receptor current flows. OHBs have larger gating-spring stiffnesses than other types of hair bundles, but we have a poor understanding of how gating-spring stiffness contributes to OHB mechanics and receptor-current regulation. Using experimentally-constrained mathematical models of the OHB, we show that the increased gating-spring stiffness in an OHB increases its stiffness and damping. The OHB’s 3D morphology reduces the contribution of gating-spring stiffness to OHB stiffness, reduces the contribution of MET-channel gating to OHB stiffness and damping, but causes additional OHB damping that rises with gating-spring stiffness. Gating-spring stiffness increases the OHB’s receptor current but decreases its displacement-current dynamic range. Strikingly, the OHB’s 3D morphology causes its force-current dynamic range to decrease with gating-spring stiffness. Our results suggest a trade-off between threshold and dynamic range regulated by OHB gating-spring stiffness.

Abstract 4138514: From Treatment to Trigger: A Case of Atomoxetine-Induced Brugada Pattern

Introduction: Brugada syndrome is an inherited cardiac disorder characterized by specific ECG patterns, notably the coved-type ST-segment elevation in the right precordial leads (V1-V3), leading to an increased risk of sudden cardiac death. This condition often stems from mutations in the SCN5A gene, which impair cardiac sodium channel function. The manifestation of Brugada Pattern, showing typical ECG findings without clinical criteria like sudden cardiac arrest or syncope, is significant. We highlight a case where atomoxetine, a selective norepinephrine reuptake inhibitor used for ADHD, unveiled a type 1 Brugada pattern. Case Presentation: A 26-year-old male with a history of ADHD on atomoxetine only presented to the emergency department with sudden substernal chest pain radiating to his left arm. His initial ECG showed right bundle branch block and type 1 Brugada pattern (Figure.1). Despite normal troponin levels and a negative coronary CT angiography, the patient's ECG abnormalities raised concerns. With no personal or familial history of arrhythmia or SCD and no other medications, atomoxetine was suspected as the trigger. Upon discontinuation, the patient's ECG type 1 Brugada pattern resolved (Figure. 2), and he remained asymptomatic with a normal Holter monitor at a 1-month follow-up. Discussion: Brugada syndrome is marked by dynamic ECG abnormalities, which can surface due to triggers like fever, certain medications, and electrolyte imbalances. Atomoxetine, an ADHD treatment and selective norepinephrine reuptake inhibitor, affects the human cardiac sodium channel (hNav1.5), encoded by the SCN5A gene. This interaction can disrupt heart action potentials, leading to conditions like long QT syndrome and Brugada pattern, by slowing cardiomyocyte depolarization and conduction. Its effect on hNav1.5 resembles that of antidepressants like Fluoxetine, increasing the risk of Brugada pattern. In our case, a patient's type 1 Brugada pattern, with no underlying heart disease or family history, pointed to atomoxetine as the cause. Discontinuing the drug resolved the ECG abnormalities. Conclusion: This case emphasizes the importance of assessing cardiovascular risk before prescribing atomoxetine, especially in individuals at risk for cardiac sodium channel dysfunctions. Immediate intervention and monitoring are critical to prevent severe arrhythmias.

Unlocking the Mysteries of Academic Writing: A Corpus-based Analysis of Lexical Bundles in L2 English for Engineering Students

This study examines the use of lexical bundles in reports produced by university-level L2 English writers in civil and environmental engineering (CEE). The corpus consists of 119 reports, and the study compares the use of different types of lexical bundles (3-word, 4-word, and 5-word) in high-scoring and low-scoring papers. The results show that high-scoring papers use a wider range of lexical bundles, and that the use of lexical bundles varies by discipline. The study also identifies specific features of the lexical bundles that contribute to score differences. The findings suggest that teaching lexical bundles and vocabulary can improve the academic writing of engineering students. The paper concludes by calling for further research on the impact of formulaic expressions on attainment scores in L2 writing.

Anatomía del pecíolo de 16 especies de Polypodiaceae presentes en México

Background and aims: Several works have shown that the petiole possesses useful anatomical characteristics for differentiating groups. Therefore, we carried out a descriptive and comparative anatomical study of the basal, middle, and apical regions of the petiole of 16 species belonging to 8 genera of Polypodioideae growing in Mexico, to identify anatomical characters that can contribute to their delimitation and identification M&M: Samples were collected from the basal, middle, and apical regions of the petiole and processed according to the paraffin embedding technique to obtain permanent preparations. The generated information was evaluated through a clustering analysis and a principal component analysis. Results: All petioles showed an unistratified epidermis, a cortex differentiated into external and internal, and vascular bundles with Polypodium-type distribution. Differences were registered in the petiole diameter, indument type, circumendodermal band, and number of vascular bundles. Four types of external cortex are recognized and the presence of nectaries in Campyloneurum amphostenon and C. costatum is reported for the first time, as well as the glandular hairs inserted at the base of the scales in Microgramma percussa. Identification keys were elaborated. Conclusions: The anatomical characteristics of the petiole allow us to differentiate taxonomically the genera and most of the species analyzed, the most important traits being the petiole diameter, the characteristics of the circumendodermal band, and the presence of aerophores and/or wings

Lexical Bundle Patterns in Malaysian Educational Texts: A Corpus-Based Analysis of English Language Textbooks

In the era of digital learning, understanding the linguistic input in educational materials is vital for language acquisition. Lexical bundles, or recurring word sequences, significantly contribute to developing fluency and coherence, especially in academic contexts. This study examines the presence and types of lexical bundles in Malaysian Form 4 and Form 5 KBSM English textbooks, analyzing their frequency and functions. Using a mixed-method design with a corpus-based approach, data were collected from textbook reading passages and analyzed with AntConc 3.4.3 software. The study aims to assess whether these textbooks provide sufficient linguistic input to enhance students' English proficiency in academic contexts. The findings show a limited presence of lexical bundles, with 29 different 3-word bundles appearing 203 times in total. Four-word bundles were not found in the corpus. The bundles were categorized into three functional types based on Biber et al.'s (2004) taxonomy; stance expressions (55.2%), referential expressions (44.8%), and discourse organizers which were absent. This gap suggests a shortfall in the textbooks' ability to guide students in creating coherent and well-structured texts. The study emphasizes the need for more comprehensive inclusion of lexical bundles in textbooks to better support language acquisition and academic proficiency. It recommends that future textbooks incorporate a broader range of lexical bundles to better equip students for advanced language uses. This research contributes to discussions on the effectiveness of educational materials in second language learning and highlights the importance of targeted linguistic input.

Lexical bundles in three oral corpora of university students

On the basis of previous lexical bundle studies, this paper examines the forms, structures and functions of 4-word bundles in three corpora of spoken English, one of them of native speakers of English and the remaining two of non-native speakers of English, corresponding to university students in their first year of an English Studies degree and to the same students after two years of university instruction. The study focuses on three major characteristics: the overall distribution of bundles, their typical structures and their functions. The findings show significant differences in the types of lexical bundles used by native and non-native students, as well as in their structure and function. Our results support the idea that lexical bundles are important components in oral discourse. One of the pedagogical implications of this paper is that Spanish students should be exposed to more samples of spoken language.

Anchoring decisions: the role of decoy pricing in consumer choices

PurposeHospitality firms aim to increase their profits by implementing a variety of marketing activities, including using decoy pricing to provide alternative choices for consumers. Decoys are relatively higher-priced offerings that signal lower value than the other offerings in the consideration set. The purpose of this research is to investigate the influence of decoy pricing on consumer choices across various contexts in the foodservice and hotel industries.Design/methodology/approachAcross the pilot and four main studies, the current research employs a sequential exploratory mixed-method design to investigate the influence of decoy pricing in the foodservice and lodging industries. The qualitative part of this research was based on two focus groups, followed by a pilot study and four main study experiments.FindingsThe results show that decoy pricing escalates consumers’ choices of more expensive product bundles in both restaurant and hotel cancellation policy contexts. However, decoy pricing does not increase the selection of more expensive hotel product bundles.Originality/valueWhile decoy pricing has been utilized as an effective revenue maximization strategy for product placement in retail stores, less is known about how promotional advertisements with decoy offers influence hotel and restaurant customers to choose more costly options. Specifically, this is the first study that explores whether decoy pricing and product/service bundling can encourage customers to select more expensive offers in hotel and restaurant contexts, considering the types of hospitality bundles that may limit this effect.

3D morphology of an outer-hair-cell hair bundle increases its displacement and dynamic range

In mammals, outer-hair-cell hair bundles (OHBs) transduce sound-induced forces into receptor currents and are required for the wide dynamic range and high sensitivity of hearing. OHBs differ conspicuously in morphology from other types of bundles. Here, we show that the 3D morphology of an OHB greatly impacts its mechanics and transduction. An OHB comprises rod-like stereocilia, which pivot on the surface of its sensory outer hair cell. Stereocilium pivot positions are arranged in columns and form a V shape. We measure the pivot positions and determine that OHB columns are far from parallel. To calculate the consequences of an OHB’s V shape and far-from-parallel columns, we develop a mathematical model of an OHB that relates its pivot positions, 3D morphology, mechanics, and receptor current. We find that the 3D morphology of the OHB can halve its stiffness, can double its damping coefficient, and causes stereocilium displacements driven by stimulus forces to differ substantially across the OHB. Stereocilium displacements drive the opening and closing of ion channels through which the receptor current flows. Owing to the stereocilium-displacement differences, the currents passing through the ion channels can peak versus the stimulus frequency and vary considerably across the OHB. Consequently, the receptor current peaks versus the stimulus frequency. Ultimately, the OHB’s 3D morphology can increase its receptor-current dynamic range more than twofold. Our findings imply that potential pivot-position changes owing to development, mutations, or location within the mammalian auditory organ might greatly alter OHB function.

Incentivizing Healthy Food Choices Using Add-On Bundling: A Field Experiment

Problem definition: How can retailers incentivize customers to make healthier food choices? Price, convenience, and taste are known to be among the main drivers behind such choices. Unfortunately, healthier food options are often expensive and not adequately promoted. However, we are observing recent efforts to nudge customers toward healthier food. Methodology/results: In this paper, we conducted a field experiment with a global convenience store chain to better understand how different add-on bundle promotions influence healthy food choices. We considered three types of add-on bundles sequentially: (i) an unhealthy bundle (when customers purchased a coffee, they could add a pastry for $1), (ii) a healthy bundle (offering a healthy snack, such as fruit, vegetable, or protein, as a coffee add-on for $1), and (iii) a choice bundle (the option of either a pastry or a healthy snack as an add-on to coffee for $1). In addition to our field experiment, we conducted an online laboratory study to strengthen the validity of our results. Managerial implications: We found that offering healthy snacks as part of an add-on bundle significantly increased healthy purchases (and decreased unhealthy purchases). Surprisingly, this finding continued to hold for the choice bundle, that is, even when unhealthy snacks were concurrently on promotion. However, we did not observe a long-term stickiness effect, meaning that customers returned to their original (unhealthy) purchase patterns once the healthy or choice bundle was discontinued. Finally, we show that offering an add-on choice bundle is also beneficial for retailers, who can earn higher revenue and profit. Funding: This research was supported by the James McGill Scholar Award Fund, the Scale AI Chair Program, IIVADO (Institut de valorisation des données) Fundamental Research Project Grant, and two Discovery Grants from the Natural Sciences and Engineering Research Council of Canada. Supplemental Material: The online appendix is available at https://doi.org/10.1287/msom.2023.0336 .

Care bundles for women during pregnancy, labour/birth, and postpartum: a scoping review

Background Care bundles, introduced in 2001, are described as a set of at least three evidence-based healthcare interventions delivered together in a clinical care episode by all healthcare providers. Although widely implemented in some healthcare areas, care bundle use in maternity care appears relatively recent. To identify the types of care bundles that have been developed, evaluated, or implemented for women during the perinatal period, we undertook a scoping review. Methods Joanna Briggs Institute methodological guidance for scoping reviews was used. MEDLINE, CINAHL, Embase, Maternity and Infant Care, and Epistemonikos were searched from January 2000 to October 2023. Records that reported on women during pregnancy and up to six-weeks postpartum as the intended or actual recipients of a care bundle, were included. The concept of interest was development, evaluation, or implementation of a care bundle. The context was maternity care provision, in any setting or geographical location. Results The search yielded 147 eligible records of which 69 originated in the USA. Most records were concerned with care bundle evaluation (n=74), and most were published in the last five-years (n=95). Eleven categories of clinical conditions were identified. These were surgical site infection, obstetric haemorrhage, perineal trauma, sepsis, stillbirth, hypertension, safe reduction of caesarean section, enhanced recovery after caesarean, placenta accrete, perinatal anxiety/depression, and ‘other’ which contained 21 records reporting on care bundles for one clinical condition. Few clinical conditions had good overlap of care bundle elements. Systematic reviews based on data from non-randomised studies may be feasible for some clinical conditions. Conclusions This scoping review provides comprehensive insight on care bundles in maternity care. Few studies were found that evaluated the effectiveness of these bundles, and many bundles for similar clinical conditions contained diverse elements. A more global approach to care bundle development, evaluation, and implementation in maternity care is recommended.

How to Retain My Consumers? Investigating Incumbents’ Promotional Strategies Upon New Business Entry in the Online-to-Offline Context

ABSTRACT The online-to-offline (O2O) business mode has on-demand features to offer consumers instant fulfillment from a local store upon their online order. The O2O mode has attracted many more consumers recently. Using empirical evidence from a leading O2O platform in China, our study focuses on the market entry issue in the O2O context. Upon the new entrant entering the market, existing listed sellers implement a higher overall promotion to their consumers by enlarging the direct promotion extent but reducing the other types of promotions, including coupon, bundle, quantity, and gift promotions. However, the O2O platforms reduce the promotions level to the consumer orders from the existing listed sellers. The platform’s and existing listed sellers’ promotions increase consumers’ purchase frequency but lower their purchase amount per order. The extent of these impacts depends on the geographic location of the new entrant. Our findings provide guidelines for the O2O platforms and listed providers to implement appropriate promotion strategies to attract consumers when considering the impact of certain new providers entering the O2O market.

Numerical investigation of the influence of the heat exchange structure on the gas-liquid dispersion in a large-scale fermenter

A combination of computational fluid dynamics (CFD) and population balance model (PBM) was used to study the gas-liquid mixing conditions in a fermenter. The effects of the heat exchange structure on the flow structure, gas holdup, agitator power, bubble size distribution and interfacial area were investigated by numerical simulations. The simulation results showed that radial gas dispersion and liquid penetration are strongly hindered by the spiral heat exchanger, as there is no gap between the annular tubes at the circumference. An unstable flow structure, gas accumulation around the shaft and gas leakage, as well as large bubbles around the heat exchange tubes are due to the poor gas distribution. By increasing the spacing of heat exchange tube bundles in circumferential, the gas-liquid mixing in the fermenter is gradually improved with the uniform row heat exchanger, the compact row heat exchanger and the bundle type heat exchanger. The bundle heat exchanger acts as a baffle to suppress the large bubbles and effectively reduce the bubbles sizes and promote gas dispersion, which exhibits the maximum interfacial area and interfacial area per unit power. Compared to the fermenter with a spiral heat exchanger, the interfacial area and interfacial area per unit power of the fermenter with a bundle heat exchanger increase by 36.5 % and 9.1 %, respectively.

The Temporal and Spatial Evolution Characteristics and Driving Factors of Ecosystem Service Bundles in Anhui Province, China

Identifying ecosystem service bundles and their long-term evolutionary characteristics is essential for the overall enhancement of regional ecosystem services, as well as the division and management of functional areas, providing a basis for decision-making in formulating ecological and environmental protection policies, as well as regional development planning. Based on land use, remote sensing, and meteorological data obtained from Anhui Province, this study assessed six important ecosystem service functions, including food production (FP), water yield (WY), carbon sequestration (CS), soil conservation (SC), habitat quality (HQ), and landscape aesthetics (LA), at the township scale in 2000, 2010, and 2020. On this basis, the k-means clustering method was used to identify ecosystem service bundles, analyze the spatio-temporal evolution trajectory of service bundles, and explore the driving factors of the spatio-temporal evolution of ecosystem service bundles using GeoDetector 2015 The results indicate the following: (1) At the spatial level, diverse ecosystem services demonstrate pronounced spatial differentiation. The distribution pattern of HQ, carbon fixation, and SC services is generally lower in the north and higher in the south, with areas of high value predominantly located in the western Dabie Mountains and the mountains of Southern Anhui. Conversely, FP services exhibit the reverse pattern, and WY services display a gradual increase from north to south, while cultural services are more dispersed, with areas of high value primarily located in the western Dabie Mountains, the Yangtze River Basin, and other locations. On the temporal scale, WY, SC, and FP services mainly exhibit an increasing trend, marked by a significant increase, whereas other services tend to present a decreasing trend. (2) Anhui Province can be categorized into four distinct types of service bundles: the grain production bundle (GPB), mountain ecological conservation bundle (MECB), urban living bundle (ULB), and core protection bundle (CPB). Ecosystem service bundles exhibit clear spatial differentiation, and identical service bundles demonstrate substantial clustering in space. Between 2000 and 2020, ecosystem service bundles displayed a marked spatio-temporal evolution, with the prevalence of GPBs diminishing, whereas the share of ULBs progressively increased, and the number of MECBs and CPBs remained largely stable. (3) In the spatio-temporal evolution process, the average annual precipitation, the proportion of forest land, and slope constitute the principal natural factors influencing the spatio-temporal evolution of ecosystem service bundles, while the proportion of construction land represents the primary socio-economic factor, with natural factors exerting a more significant influence than socio-economic factors.

Analysing the Functions of Lexical Bundles for Teaching Academic Writing to Graduate Students

Academic writing skills contribute greatly in academic performance. One of the key elements of good academic writing is to know the proper use of the strings of the words usually occur together. These words are termed as lexical bundles in corpus linguistics. Some research has been conducted on the use and functions of lexical bundles in spoken and written discourses (Chen & Chen, 2020). However, there is scarce research on the functions of lexical bundles and their use in Pakistani research writing. While drawing on the corpus of 90201 corpora of the 12 Pakistani research articles, we investigated the functions and use of lexical bundles in research papers of Pakistani authors. The list of the lexical bundles by Simpson-Vlach and Ellis (2010) was used as a source to interpret the lexical bundles. We found the referential expressions were the highest lexical bundles in research articles of Pakistani authors followed by the expressions of ability and possibility and hedges in the list. Based on these findings, we argue that Pakistani authors are aware about the various types of the lexical bundles and their functions in academic writing. It is suggested that the high-frequency bundles can help the learners to improve the use of modal words used as hedges in academic writing. As per the findings of this study, it is recommended that a large corpus may be built for better results in the future.

Performance and community acceptance of paddy management with balanced input cultivation technology in Kebonagung Village Madiun East Java Indonesia

By integrating balanced rice growing technology components, getting rice organoleptic tests from the rice produced, and learning about the community acceptability of the applied technology components, this study seeks to ascertain the growth response and NSV production of specific and site-specific rice. The study was carried out in rice paddies. five different types of technology bundles in a randomized group trial design. Each treatment unit and replication in the five iterations of the experiment used 0.3 ha. Acceptance in the community using a survey approach with fifty participants. The results indicated that the Inpari 42 and Inpari 45 seedlings developed the tallest plants between 77 and 81 days after planting. Inpari 32 had the most tillers, which was the same as Inpari 42 and Pamelen. Pamelen yielded the most productive tillers and the least amount of non-productive tillers. The largest plant height was measured 98–102 days following the Inpari 42 seedlings, while the highest number of tillers were found in Pamelen, Inpari 32, and Inpari 42. Inpari 42 has the widest flag leaf area. The most abundant grain component produced by Inpari 42 is the number of grains per panicle and the full grain per panicle. The highest production is produced by Inpari 32. The panelists' favored rice varieties were Inpari 32, Inpari 42, and Inpari 45 based on the rice's organoleptic test results (color, aroma, taste, and texture). Inpari 32, Inpari 45, and Inpari Nutrizinc rice had greater brightness. Inpari 45 is yellowish, and Pamelen is quite red. Pamelen and Inpari Nutrizinc are the same. The high adoption rate of 8766 % and the rapid diffusion of applied technology to nearby villages and other regions indicate that the community has a very positive attitude toward technology.

Bond behavior between bundled composite bars and concrete using beam-end pullout tests

Bundled reinforcement can improve construction efficiency by reducing the number of connectors required. The steel-fiber reinforced polymer (FRP) composite bar (SFCB) is a novel reinforcement with high strength, moderate modulus of elasticity and good durability. Four groups of pullout tests were carried out, with parameters including the number of bars within each bundle, bonded length, and rebar type (steel bar, BFRP bar, SFCB). The failure modes of bar pullout without or after yielding, rebar fracture, and concrete splitting were observed. Compared to the single-bar specimen, the two-bar and three-bar bundled specimens resulted in approximately 30% and 40% decrease in average bond strength. The yielding slip sy of the three-bar bundled SFCB specimen is 3.8 times that of the single-bar specimen, indicating that bundled reinforcement can effectively control sy. A simplified bond strength prediction method and a bond stress-slip constitutive model based on the equivalent effective area approach are proposed. Finite element (FE) models were established and verified, and the failure modes of bar fracture are obtained by varying the bonded lengths for different bundled reinforcements, the ultimate slip of four-bar bundled BFRP bars increased by 127%. Recommendations for the development length of bundled SFCBs are proposed based on the FE results, which provide enough safety redundancy.

Pharmacognostic study of Catharanthus roseus (L.) G. Don, growing in Uzbekistan

In the article, the morpho-anatomical structure of the leaf and stem of Catharanthus roseus species distributed in the local conditions of Uzbekistan was studied, and it was determined that biologically active substances are found in the leaf mesophyll and bark parenchyma of the stem. The following diagnostic characters were determined: in the leaf – dorsiventral type of leaf mesophyll; thick-walled outer walls of the epidermis; amphistomatic leaves; not submerged stomata; chlorophyll-bearing palisade and spongy parenchyma; closed collateral type of conduction bundles; the presence of numerous idioblasts; in the stem there is a more lignified, non-tufted type of structure; libriform extensive; radial rays elongated and short; phloem is extensive, located between the crustal parenchyma and the libriform; the core is not wide, represented by large and small round-oval, thin-walled parenchyma cells containing hydrocyte cells and numerous laticifers. The content of moisture, ash, extractives extracted by heteropolar extractants was also studied, determined by pharmacopoeial methods to establish authenticity and prepare draft regulatory documentation for plant raw materials.

Sealing method and experimental study of large-diameter reverse circulation hole hammer

A reliable sealing structure is the key to achieving reverse circulation drilling technology for large- diameter reverse circulation down the hole hammers, and it is also a difficult point in the design of large- diameter reverse circulation down the hole hammers. The existing large-diameter reverse circulation down the hole hammers are designed based on the sealing structure of the bottom drilling tool body. This article proposes a joint sealing method for hole bottom and hole opening. Based on this sealing method, a bundle type reverse circulation down the hole hammer and hole opening sealing device with a diameter of 710/311mm were developed for hole expansion, and field tests were conducted with a double wall drilling tool with a diameter of 127/70mm. The method achieved good continuous reverse circulation slag removal effect, with an average mechanical drilling speed of 2.1m/h, which is 2.6 times higher than the conventional roller bit hole expansion method. The experimental results indicate that the joint sealing method between the bottom and the mouth of the hole is feasible and worthy of further promotion and application.

Supply-demand bundles and ecological function management of urban ecosystem services: Taking central urban area of Qiqihar as an example

The comprehensive management of multiple ecosystem services is the focus of current research in the field of ecosystem service. The ecological space in the central urban area is scarce, but ecological needs are diverse. How to scientifically use urban land while considering various ecological functions has gradually become an academic hotspot. Taking the central urban area of Qiqihar as an example, we applied the ecosystem service bundle theory to analyze the supply and demand relationship of five ecosystem services in the study area, including flood regulation, air purification, carbon storage and sequestration, biodiversity conservation, and cultural recreation. Based on the supply-demand ratio, we identified the supply-demand bundles of ecosystem services in the study area, completed the division of ecological functional areas, and proposed corresponding spatial control strategies. The results showed that the supply of those five services presented a spatial pattern of low in the city center and south side, while high in the northwest and southeast side, and that the demand for those five services presented a spatial pattern of high in the city center and low around the city. Air purification, biodiversity conservation, and cultural recreation ser-vices were in short supply, with a supply-demand ratio of -0.160, -0.071, and -0.008, respectively. The supply to demand ratios of flood regulation and carbon storage and sequestration services were in excess, with a supply to demand ratio of 0.089 and 0.008, respectively. The spatial imbalance between supply and demand of various services was significant. The research area could be divided into six types of ecosystem service bundles. After comprehensive analysis, the research area would be further divided into four types of zones: urban ecological restoration zone, urban ecological strengthening zone, urban development transition zone, and urban ecological conservation zone. We proposed targeted functional optimization strategies based on the spatial relationship, ecological background characteristics, and supply and demand ratios of various services within the zone.