AN M[X]/G/1M^{[X]}/G/1 QUEUE WITH OPTIONAL SERVICE AND WORKING BREAKDOWN

In this study, a batch arrival single service queue with two stages of service (second stage is optional) and working breakdown is investigated. When the system is in operation, it may breakdown at any time. During breakdown period, instead of terminating the service totally, it continues at a slower rate. We find the time-dependent probability generating functions in terms of their Laplace transforms and derive explicitly the corresponding steady state results. Furthermore, numerous measures indicating system performances, such as the average queue size and the average queue waiting time, has been obtained. Some of the numerical results and graphical representations were also presented

Оценка противоречивости логической структуры учебного плана

Purpose of the study. The main purpose of creating a curriculum is to regulate academic disciplines in accordance with the logic of the learning process, defined by the relationship between the basic concepts of the disciplines. Violation of this logic becomes apparent only directly during the training sessions.A large variety of quantitative methods uses indicators that do not reveal structural deficiencies in the curriculum. This makes it difficult to improve the curriculum.The purpose of this work is to demonstrate the application of a general approach to the assessment of the structural inconsistency of systems in relation to the evaluation of the logical structure of the curriculum.Materials and methods. The paper applies a general approach to the assessment of structural integrity, developed on the basis of the provisions of the general theory of systems and graph theory. The approach involves the construction of three interrelated structural models of the system and using them to determine the initial data for calculating the index of inconsistency of the system structure.Results. The overall approach to the assessment of structural integrity is adapted to assess the logical structure of the curriculum. Three models of curriculum structure are developed:Elementary model of interdisciplinary communication;Curriculum network model;Hierarchical curriculum model.Based on the parameters of the hierarchical curriculum model, using three adapted algorithms, the value of the inconsistency index of the curriculum structure in the direction of preparation “Applied Informatics” is calculated. Recommendations on changing the structure of the studied curriculum to reduce the degree of its structural inconsistency are proposed. Conclusion. As a result of the research, the methods were proposed that allow identifying possible contradictions in the structure of the curriculum and evaluating its inconsistency. As the experiments have shown, it is extremely difficult to study the curricula in a manual manner, the number of disciplines in which exceeds 50. In this regard, the development of a complex of computer programs that will automate the assessment of the inconsistency of large curricula is being completed.Цель исследования. Основной целью создания учебного плана является упорядочение учебных дисциплин в соответствии с логикой процесса обучения, определенной взаимосвязями между основными понятиями дисциплин. Нарушение данной логики становится очевидным только непосредственно в ходе проведения учебных занятий.Большое разнообразие количественных методов используют показатели, которые не позволяют выявить структурные недоработки учебного плана. Это затрудняет процесс улучшения учебного плана.Целью данной работы является продемонстрировать применение общего подхода к оценке структурной противоречивости систем применительно к оценке логической структуры учебного плана.Материалы и методы. В работе применен общий подход к оценке структурной целостности, разработанный на основе положений общей теории систем и теория графов. Подход предусматривает построение трех взаимосвязанных структурных моделей системы и определения с их помощью исходных данных для расчета показателя противоречивости структуры системы.Результаты. Общий подход к оценке структурной целостности адаптирован для оценки логической структуры учебного плана. Разработаны три модели структуры учебного плана:– элементарная модель междисциплинарных связей;– сетевая модель учебного плана;– иерархическая модель учебного плана.На основе параметров иерархической модели учебного плана с использованием трех адаптированных алгоритмов рассчитано значение показателя противоречивости структуры учебного плана по направлению подготовки Прикладная информатика. Предложены рекомендации по изменению структуры исследуемого учебного плана для понижения степени его структурной противоречивости.Заключение. В результате проведенных исследований предложена методика, которая позволяет выявить возможные противоречия в структуре учебного плана и дать оценку его противоречивости.Как показали проведенные эксперименты, исследовать ручным способом учебные планы, количество дисциплин в которых превышает 50, крайне сложно. В связи с этим завершается разработка комплекса компьютерных программ, которые позволят автоматизировать оценку противоречивости больших учебных планов

Biochemical and immunohistochemical charterisation of mucins in 8 cases of colonic disease - a pilot study

Objectives: To characterise mucins in cancer of the colon and compare these with controls using stringent biochemical measures to avoid endogenous proteolysis. Design: Crude mucus scrapings were collected from 12 specimens obtained by colectomy. Specimens from 3 traumatic colectomies and 1 sigmoid volvulus were used as controls, and compared with 6 specimens from colons resected for adenocarcinoma and 2 irradiated colons. Subjects: The median age of the 4 female patients was 76 years (range 49 - 82 years), and of the 8 male patients 46.5 years (range 16 - 74 years). Results and conclusions: The crude mucus scrapings in the 9 specimens ranged in weight from 353 mg to 7 697 mg (median 4 928 mg). The median of purified mucin in the 9 specimens was 0.72 µg/mg wet weight of scraped material. Eight samples gave non-extractable pellet material, and were treated with DTT to reduce disulphide bonds for further analysis. One of these 8 pellets was resistant to reduction and had to be digested with papain before analysis. Only 5 of these pellets had mucin. Gel filtration and SDS-PAGE (sodium dodecyl sulphate polyacrylamide gel electrophoresis) analysis revealed different populations of mucin based on size and extent of degradation. Western blotting and immunohistochemical analysis confirmed the presence of MUC2 in all samples, MUC5AC in 2 and MUC5B in 5 diseased specimens. Immunohistochemical analysis showed that there was no MUC1 in the normal specimens, MUC1 apoprotein MUC1 core) in 2 cancer specimens and MUC1 in 1 cancer specimen. Histochemical analysis showed that normal tissue expressed neutral and acidic mucins and diseased specimens predominantly expressed acidic mucins. The electrophoretic behaviour of MUC2 in sigmoid volvulus was different from that in cancer of the colon

Integrating Spatial Educational Experiences (Isee) – Mapping a New Approach to Teaching and Learning Soil Science

The purpose of the Integrating Spatial Educational Experiences project is to develop the ability of our students to use digital maps: (1) to learn how and why soils and landscapes vary spatially at scales ranging from fields, to counties, states, and globally and (2) to learn how the spatial distribution of soils and landscapes impacts the distributions of land use, and environmental and ecosystem services across various scales. Our immediate audience is undergraduate students in soil, crop, natural resource, and environmental science curricula in colleges and universities, but the products created by this project will have broader uses for outreach to other clientele. Products to support teaching and learning include: (1) a revised and expanded Integrating Spatial Educational Experiences (Isee) web site, (2) maps of soil properties for Indiana, West Virginia, Ohio, Kentucky, Illinois, Wisconsin, and Texas, (3) a community of practice dedicated to Integrating Spatial Educational Experiences in soil science education on STEMEdhub.org, and (4) lessons, worksheets, exercises, and experiences shared with the Isee community of practice

COOL-LAMPS III: Discovery of a 25".9 Separation Quasar Lensed by a Merging Galaxy Cluster

In the third paper from the COOL-LAMPS Collaboration, we report the discovery of COOL J0542-2125, a gravitationally lensed quasar at $z=1.84$, observed as three images due to an intervening massive galaxy cluster at $z=0.61$. The lensed quasar images were identified in a search for lens systems in recent public optical imaging data and have separations on the sky up to 25".9, wider than any previously known lensed quasar. The galaxy cluster acting as a strong lens appears to be in the process of merging, with two sub-clusters separated by $\sim 1$ Mpc in the plane of the sky, and their central galaxies showing a radial velocity difference of $\sim 1000$ km/s. Both cluster cores show strongly lensed images of an assortment of background sources, as does the region between them. A preliminary strong lens model implies masses of $M(<250\ \rm{kpc}) = 1.79^{+0.16} _{-0.01} \times 10^{14} M_{\odot}$and$M(<250\ \rm{kpc}) = 1.48^{+0.04}_{-0.10} \times 10^{14} M_{\odot}$ for the East and West sub-clusters, respectively. This line of sight is also coincident with a ROSAT ALL-sky Survey source, centered between the two confirmed cluster halos reminiscent of other major cluster-scale mergers.Comment: 13 pages, 6 figures. Submitted to Ap

COOL-LAMPS VI: Lens model and New Constraints on the Properties of COOL J1241+2219, a Bright z = 5 Lyman Break Galaxy and its z = 1 Cluster Lens

We present a strong lensing analysis of COOL J1241+2219, the brightest known gravitationally lensed galaxy at $z \geq 5$, based on new multi-band Hubble Space Telescope (HST) imaging data. The lensed galaxy has a redshift of z=5.043, placing it shortly after the end of the Epoch of Reionization, and an AB magnitude z_AB=20.47 mag (Khullar et al. 2021). As such, it serves as a touchstone for future research of that epoch. The high spatial resolution of HST reveals internal structure in the giant arc, from which we identify 15 constraints and construct a robust lens model. We use the lens model to extract cluster mass and lensing magnification. We find that the mass enclosed within the Einstein radius of the z=1.001 cluster lens is M(<5.77'')=$1.079^{+0.023}_{-0.007}$, significantly lower than other known strong lensing clusters at its redshift. The average magnification of the giant arc is $=76^{+40}_{-20}$, a factor of $2.4^{+1.4}_{-0.7}$ greater than previously estimated from ground-based data; the flux-weighted average magnification is $=92^{+37}_{-31}$ We update the current measurements of the stellar mass and star formation rate (SFR) of the source for the revised magnification, $\log(M_\star/M_{\odot})=9.7\pm0.3$ and ${\rm SFR} = 10.3^{+7.0}_{-4.4}$ $M_{\odot}$yr$^{-1}$. The powerful lensing magnification acting upon COOL J1241+2219 resolves the source and enables future studies of the properties of its star formation on a clump-by-clump basis. The lensing analysis presented here will support upcoming multiwavelength characterization with HST and JWST data of the stellar mass assembly and physical properties of this high-redshift lensed galaxy.Comment: Submitted to Ap

COOL-LAMPS. VI. Lens Model and New Constraints on the Properties of COOL J1241+2219, a Bright z = 5 Lyman Break Galaxy and its z = 1 Cluster Lens

We present a strong lensing analysis of COOL J1241+2219, the brightest known gravitationally lensed galaxy at z ≥ 5, based on new multiband Hubble Space Telescope (HST) imaging data. The lensed galaxy has a redshift of z = 5.043, placing it shortly after the end of the “Epoch of Reionization,” and an AB magnitude z AB = 20.47 mag (Khullar et al.). As such, it serves as a touchstone for future research of that epoch. The high spatial resolution of HST reveals internal structure in the giant arc, from which we identify 15 constraints and construct a robust lens model. We use the lens model to extract the cluster mass and lensing magnification. We find that the mass enclosed within the Einstein radius of the z = 1.001 cluster lens is M(<5.″77)=1.079−0.007+0.023×1013M☉ , significantly lower than other known strong lensing clusters at its redshift. The average magnification of the giant arc is 〈μ arc〉 = 76−20+40 , a factor of 2.4−0.7+1.4 greater than previously estimated from ground-based data; the flux-weighted average magnification is 〈μ arc〉 = 92−31+37 . We update the current measurements of the stellar mass and star formation rate (SFR) of the source for the revised magnification to log(M⋆/M⊙)= 9.7 ± 0.3 and SFR = 10.3−4.4+7.0 M ⊙ yr−1, respectively. The powerful lensing magnification acting upon COOL J1241+2219 resolves the source and enables future studies of the properties of its star formation on a clump-by-clump basis. The lensing analysis presented here will support upcoming multiwavelength characterization with HST and JWST data of the stellar mass assembly and physical properties of this high-redshift lensed galaxy

Empowering citizen-led adaptation to systemic climate change risks

The increasing impacts of climate change instigate the need for adaptation. However, most adaptation initiatives focus on actions by government or businesses, despite growing calls for communities on the frontline of climate risks to be involved in planning and selecting strategies. Here, we appraise a pilot process using participatory systems mapping with citizens to identify 1) diverse threat vectors for local climate impacts and 2) context-relevant interventions to protect households and communities while 3) considering synergies and tradeoffs with other socially desirable outcomes. We tested the pilot process in communities in the lower Volta Basin in Ghana, the Assam region in India, and Southern England. From participants' perspectives, the process increased awareness of- and preparedness for climate change impacts and raised essential learning points for upscaling citizen-led adaptation approaches. These include understanding multiple outcomes of interventions, barriers, and enablers to implementation, and sensitivity of co-design to regional geography and socio-cultural context