Small Category Research Articles

Village Potential Analysis Based on the Developing Village Index Using the Fuzzy Logic Method (Case Study: Village in Cikampek District, Karawang District)

Village Potential or abbreviated Podes are social, economic, and ecological resources found in the Village, which can be developed to improve the welfare of the Village community. However, sometimes Podes are not aware of their existence in several villages in one sub-district, this is usually because the village community does not understand or even know how to develop and utilize the natural resources in the village, as well as manage human resources that can improve the standard of living of their people. Based on the statement above, the researcher intends to analyze and explore how the actual problems experienced by the Village and how big or strong the Village Potential is owned by several Villages in Cikampek District by using the Fuzzy Logic Approach. The Fuzzy Logic method will be used to identify problems that often occur in village development and find out the potential of villages in Cikampek District according to data released by BPS for Cikampek District in Figures 2018 and several criteria for Villages issued by IDM (2015). The fuzzy set created consists of 4 input variables, namely Natural Resources (SDA), Human Resources (HR), Institutions (KL), and Infrastructure (PSR), and 1 output variable, namely Village Potential (PD). According to IDM data for 2018, there are 10 villages in Cikampek District, 1 village that has the Low Village category, 2 Highest Villages, and 7 Medium Villages. However, the results of the analysis are applied and implemented in a fuzzy form. The results in each villageare potential quite good. Where the 10 villages in Cikampek District have the potential to be developed. This is because based on the results of interviews and filling out questionnaires, shows that on average 10 villages in Cikampek District have potential in the small industry category. This category of small industry potential includes the community being able to develop work industries, food needs, and clothing in each of these villages.

Handling the Challenges of Small-Scale Labeled Data and Class Imbalances in Classifying the N and K Statuses of Rubber Leaves Using Hyperspectroscopy Techniques.

The nutritional status of rubber trees (Hevea brasiliensis) is inseparable from the production of natural rubber. Nitrogen (N) and potassium (K) levels in rubber leaves are 2 crucial criteria that reflect the nutritional status of the rubber tree. Advanced hyperspectral technology can evaluate N and K statuses in leaves rapidly. However, high bias and uncertain results will be generated when using a small size and imbalance dataset to train a spectral estimaion model. A typical solution of laborious long-term nutrient stress and high-intensive data collection deviates from rapid and flexible advantages of hyperspectral tech. Therefore, a less intensive and streamlined method, remining information from hyperspectral image data, was assessed. From this new perspective, a semisupervised learning (SSL) method and resampling techniques were employed for generating pseudo-labeling data and class rebalancing. Subsequently, a 5-classification spectral model of the N and K statuses of rubber leaves was established. The SSL model based on random forest classifiers and mean sampling techniques yielded optimal classification results both on imbalance/balance dataset (weighted average precision 67.8/78.6%, macro averaged precision 61.2/74.4%, and weighted recall 65.7/78.5% for the N status). All data and code could be viewed on the:Github https://github.com/WeehowTang/SSL-rebalancingtest. Ultimately, we proposed an efficient way to rapidly and accurately monitor the N and K levels in rubber leaves, especially in the scenario of small annotation and imbalance categories ratios.

Convergent and Discriminant Validity of the Blast Exposure Threshold Survey in United States Military Service Members and Veterans.

The Blast Exposure Threshold Survey (BETS) is a recently developed and promising new self-report measure of lifetime blast exposure (LBE). However, there are no studies that have examined the psychometric properties of the BETS, which currently limits its clinical utility. The purpose of this study was to examine the convergent and discriminant validity of the BETS by comparing the BETS Generalized Blast Exposure Value (GBEV) to six variables hypothesized to be associated with LBE (i.e., single-item LBE, combat exposure, years in the military, number of combat deployments, and military occupation specialty [MOS]) and three variables hypothesized not to be associated with LBE (i.e., age at the time of injury, estimated pre-morbid Full-Scale Intelligence Quotient [FSIQ], and resilience). Participants were 202 United States service members and veterans prospectively enrolled from three military medical treatment facilities (68.7%) and via community recruitment initiatives (31.3%). Participants completed the BETS, Combat Exposure Scale (CES), Deployment Risk and Resiliency Inventory-2 Combat Experiences (DRRI-2 CE), Traumatic Brain Injury-Quality of Life Resilience scale, and a brief structured interview. For some analyses, participants were classified into two blast risk MOS groups: high (n = 89) and low (n = 94). The BETS GBEV was not significantly correlated with all three non-blast related variables (rs = 0.01 to rs = -0.12). In contrast, GBEV was significantly (p < 0.001) associated with all blast-related variables; single-item LBE (rs = 0.76), CES (rs = 0.58), number of combat deployments (rs = 0.53), DRRI-2 CE (rs = 0.48), and high blast risk MOS (r = 0.36, medium effect size). However, a stronger relationship was found between the blast-related variables and three modified GBEV scores when excluding some small weapons categories; single-item LBE (rs = 0.80-0.82), CES (rs = 0.64-0.67), number of combat deployments (rs = 0.56), DRRI-2 CE (rs = 0.51-0.53), and high blast risk MOS (r = 0.42-0.49, medium-large effect size). This is the first study to examine the psychometric properties of the BETS. Overall, these results offer support for the convergent and discriminant validity of the BETS. In order to ensure that the BETS can be confidently used as a valid and reliable measure of LBE, more research is needed to further examine the psychometric properties of the test, particularly with regard to the establishment of test-retest reliability.

Comparative Analysis of Income of KTH Pattiro and KTH Lanniti on Trigona sp Honeybee Product in Rompegading Village, Cenrana District, in District Maros

The aim of the study was to find out how much the comparison and difference in income of KTH Pattiro and KTH Lanniti in the production of honey bee forest products Trigona sp in Rompegading Village, Cenrana District, Maros Regency. The data collection method was carried out through interviews with members of the Forest Farmer Group using a questionnaire. Respondents were determined by census as many as 30 people consisting of 15 members of the Pattiro Forest Farmers Group and 15 members of the Laniti Forest Farmers Group. The results showed that the comparison or comparative income of the Pattiro forest farmer group was Rp. 17,205,000/year, with an average forest farmer group income of Rp. 1,147,000/year. Meanwhile, the Lanniti forest farmer group's income from Trigona sp madi bees is Rp. 19,241,000/year, with an average income of Rp. 1,1281,733/year with a difference in income of Rp. 2,036,000/year. Compared to the district minimum wage (UMK) of Maros district, which is around 2,135,000/month, the contribution of Trigona sp honey bees is around 5% per person per month or its contribution to income is still in the very small category.

Pendampingan Penyusunan Laporan Keuangan Oleh PT Arrasyid Trio Konsultindo Menggunakan Software Accurate Pada Pelaku UMKM

Micro Small and Medium Enterprises (MSMEs) are economic activities whose business scope is still in the small category and is usually only managed by individuals. PT Arrasyid Trio Konsultindo is the subject of this activity which acts as a financial and management consultant. The location of the implementation of mentoring activities is in 2 (two) places, namely the client PT Arrasyid Trio Konsultindo's office in Madiun, East Java and at the official office which is located at Perum Zada Regency 1, Block 11, RT 03 / RW 09, Bulakan, Sukoharjo, Central Java. CV. Argo Mulyo Sejahtera is the client who uses financial statement preparation assistance services. There are the problem encountered by CV. Argo Mulyo Sejahtera is the unavailability of financial reports that are systematic and aligns with financial accounting standard MSMEs (SAK EMKM). The purpose of the mentoring activities carried out by PT Arrasyid to CV. Argo Mulyo Sejahtera is to present more valid, effective and efficient financial statements. The methods used are observation and preparation, providing workshops on the importance of financial reports and Accurate Software, as well as monitoring and mentoring MSMEs. The results of the Financial Report Preparation Assistance are that MSME actors can find out how to prepare financial reports using Accurate software easily and efficiently.

Effects of agricultural subsidies on farm household decisions: a separable household model approach

IntroductionThis study employs a separable household model to estimate the effect of agricultural subsidies on production and consumption decisions taken by farm households. The study used data from a household survey using a pre-tested schedule to develop and calibrate an agricultural household model.MethodFirst, we calculated a price index for the model. The index was higher for non-agricultural commodity groups in all the categories of farm households. Expenditure on non-agricultural commodity groups was more than agricultural commodity groups.Result and DiscussionResults indicated that for the agricultural commodity group, the estimated coefficients of linear expenditure system (LES) model were positive and less than one for all farm household categories except for the wage-price coefficient which was found to be negative. The estimates of profit function in the study area depict that the variable inputs were negatively related to the profit function and the fixed inputs were positively related to profit. Our study highlights a few crucial points – First, the removal of subsidies will decrease the demand for electricity, concentrate and irrigation by 80, 73 and 70 %, respectively. Second, removing subsidies will not only affect the demand for inputs but will also lead to a decline in the consumption demand for both agricultural and non-agricultural commodities. Third, this effect was found to be more prominent in the small and medium categories of farm households.

Optimal stock allocation for an automated portfolio recommender system in the perspective of maximum fund utilization

“Buying or selling” a favorable combination of stocks is always challenging for non-professional investors due to its inherent complex and dynamic nature. Creating an automated Portfolio Recommender System (RS) for investors, has been an active area of research. The reliable performance of a portfolio depends on several complex factors, namely market fluctuations, market, and investors’ behavioral patterns, customers’ demographic classification, etc. In addition, the inter-relationship between the stocks needs more investigation along with the return and associated risk for the proper selection of a portfolio. In this work, the daily closing prices and volume of 297 Indian stocks from Large, Mid, and Small Cap categories from different sectors in the National Stock Exchange (NSE) of India for the FY 2021–22 have been considered. The set of dissimilar stocks has been extracted through K-means clustering using several additional parameters, namely, beta factor and proportionate volume, along with the traditional concepts of expected return and associated risk to create sample portfolios. Subsequently, the standard portfolios from the samples have been constructed utilizing Markowitz’s Modern Portfolio Theory (MPT) with a trade-off between expected return and associated risk. Next, for the purpose of comparing the maximum utilization of the investment amount, the greedy algorithm, as well as the integer programming problem, have been applied to different investment options. The associated numbers of discrete stock allocations have been obtained accordingly. The comparison shows that the greedy algorithm performs better than integer programming problem from the perspective of maximum fund utilization. The performance validation confirms that the MPT model is better than the Hierarchical Risk Parity (HRP) model, even in a period of market crisis. Finally, on the basis of different portfolio indices, the standard portfolios and other similar portfolios using the cosine similarity approach are recommended in accordance with investors’ choice.

The Combination of Architectural Art and Humanization

Art is a broad term that encompasses various virtual and practical art disciplines, of which architecture is a major category. Within the broad category of art, it seems that every small category can react with each other, creating works of higher artistic quality for the world. It is precisely because art has always upheld this characteristic that it has been continuously upgraded by people in recent years. In the process of creation, many art scholars have found that both art and architecture need to be combined with people to be better accepted by society. Film art needs to be appreciated by audiences, music art needs to be listened to by people, painting art needs to be viewed by people, installation art needs to be photographed by people, and architectural art needs to be felt by users rather than a cold empty shell. Therefore, this article describes the connection between contemporary art and architecture, which can be related to human nature. Any kind of art returns to its essence in order to reflect a phenomenon that exists in mass society, and it is displayed to the public to trigger people’s resonance and reflection. Since ancient times, the relationship between architecture and people has been complementary. In the process of designing buildings, people integrate various artistic techniques to make them respond to the site and applicable people. The final design of the building also serves the users in the building, making them feel comfortable and more efficient in completing work and life. Therefore, the art of architecture is ultimately designed and thought around human nature. In recent years, tall buildings have sprung up in cities across China, and gradually every city has its own “CBD” and landmark buildings. However, what we see more often are some cold buildings, some buildings built for the purpose of volume rate and unique shape, which often only design the strange shape shell and then hand it over to the construction party, or low-level copies of master’s design works. These examples are often cold empty shells that cannot make the people living in them feel the warmth brought by the building. I think that there is a lack of artistic and user-oriented architecture in China, rather than focusing on mass production and copying. This may change the lifestyle and quality of life of the public, and realize the humanization of architecture from the perspective of architectural art.

An Assessment On The Knowledge Level Of Farmers Regarding Paddy Straw Management In Ludhiana, Punjab

Managing paddy straw in conservation agriculture is crucial for long term sustainability of agriculture. Rice straw, which is often scattered or burned in the fields, serves multiple purposes like mushroom production, fuel for cooking, ruminant fodder, stable bedding, and paper making. The study has put forth the knowledge level of farmers regarding paddy straw management. The present study was carried out in the Ludhiana district of Punjab purposively on the basis of availability of rice growers using multistage sampling technique with 100 respondents. The study revealed that 47 per cent belong to middle age group ranging from 35-50 years. Among all, 39 per cent of the farmers have completed senior secondary education. Agriculture was the major occupation of the respondents. It has been reported that more than half of the farmers belonged to nuclear families and majority of farmers had small sized family of 2 to 5 members. The operational land holding data of the respondents was categorized into marginal, small, semi-medium, medium and large categories and the majority of farmers have large land holdings of more than 25 acres. Notably, maximum respondents demonstrated a medium knowledge level regarding paddy straw management. The overall result regarding paddy straw management indicates a mixed level of awareness. While the majority of farmers were knowledgeable about certain aspects such as preferred rice variety for extending time period for straw management and the use of a baler. The study established a positive and highly significant relationship between knowledge level and and factors like education and training.

Pelatihan Dan Pendampingan Desain Kemasan untuk Meningkatkan Branding Produk UMKM Desa Manggihan Kecamatan Getasan Kabupaten Semarang

Manggihan Village, Getasan District, Semarang Regency, which is at the foot of Mount Merbabu, is close to the Kopeng tourist destination area. This village has a population that has professional business owners in the Micro, Small, and Medium Enterprises (MSME) category in the culinary sector which makes cracker rambak, processed dry food with various types of chips And processed catfish food. The problem faced in their business is that they do not yet have a product identity in the packaging such as sticker labels, packaging that attracts potential buyers, so the message of the product has not been conveyed. This community service activity aims to provide knowledge and awareness for MSMEs about the importance of product packaging that attracts potential buyers thereby providing added value and competitive advantage for the products produced. The method used in this service is holding socialization activities on the importance of product branding, training, and assistance in making sticker labels and food product packaging design. In the mentoring process, a needs analysis is first carried out including the type of packaging material, packaging shape, packaging identity color, and product logo. It is hoped that the output targets that will be achieved through this program will help partner MSMEs increase the amount of income from sales by using new packaging and product logos designed in such a way that they are attractive to buyers. The product packaging and labels produced as the output of this activity can become an identity. a typical Manggihan Village product that differentiates it from similar products in other areas

Meta Analisis Model Pembelajaran Kooperatif Tipe Group Investigation Terrhadap Hasil Belajar Fisika Siswa Di SMA

This research takes the form of a meta-analysis aiming to encompass findings regarding the influence of the cooperative learning model called Group Investigation (GI) on high school students' physics learning outcomes. It aims to identify the independent variable, which is cooperative learning, and the dependent variable, which is high school students' physics learning outcomes. The study includes 20 journal articles on the Group Investigation cooperative learning model that align with the research objectives. The average effect size calculation resulted in an average effect size of 0.86. The average effect size based on the learning outcomes of the Group Investigation type was 0.80. It was observed that the highest level based on the class level was achieved in Grade XI with an effect size of 0.97, while Grade X also attained a high effect size. This demonstrates the effectiveness of the Group Investigation cooperative learning model, especially in Grade XI of high school. The overall percentage of journal articles categorized by effect size is as follows: high impact category 20%, very high impact category 10%, high category 20%, moderate category 30%, and finally, a small impact category with 20%. From the analysis, it's evident that journals on the Group Investigation cooperative learning model are highly relevant for use in the learning process due to their influence on students' physics learning outcomes in high school.

Domestic Energy Consumption and Its Contribution to Greenhouse Gas Emissions: Insights from Koulikoro Urban Community, Sudano-Sahelian Zone of Mali in West Africa

The objective of this study is to estimate the carbon dioxide (CO2) released by domestic energy (firewood and charcoal) in the urban commune of Koulikoro, Mali. This study employed questionnaire survey to identify the type of energies used, their costs, the quantity consumed, and the difficulties of access to these energies and their impact on natural resources in Koulikoro. The consumption of each family per neighbourhood was extrapolated to its total population to determine the carbon emitted and the carbon dioxide released. Thus, the carbon dioxide emitted in tonnes per neighbourhood was determined. The findings revealed three types of energy in the urban commune of Koulikoro, mainly firewood 72%, charcoal 25% and Gas 3%. The use of these energy sources depends on accessibility and availability. The increase in consumption per district is a function of the number of people. Daily used charcoal was estimated at 2 kg day-1 and 7 kg day-1 for firewood. Overall, average firewood using was highest in largest household size and it was 62% higher than in small size category which recorded the lowest. Annual amount of charcoal used was 676 kg year-1 and 2294 kg year-1 for firewood. However, annual amount of fuelwood per person was higher in small size category and 178% greater than in largest household group than other household size. Carbon consumption per capita per year was greater in small household group estimate to be 477 kg pns-1 year-1. Thus, the urban commune of Koulikoro has a significant carbon dioxide emission and firewood emits more CO2 than charcoal.

Macroplastic deposition and flushing in the Meuse river following the July 2021 European floods

Rivers play an important role in the macroplastics transport and retention dynamics in the environment. Therefore, gaining an understanding of these processes is vital in order to help determine the fate of macroplastic in the environment. During flood events the transport of floating macroplastic is known to increase. We compared plastic accumulation and flushing on sixteen riverbanks along the Dutch Meuse river during the period that includes the July 2021 extreme flood to plastic accumulation on the same riverbanks as during normal discharge conditions between 2018 and 2021. Here we show that following the flood small macroplastic categories ( cm) were flushed from the riverbanks, while larger soft plastic fragments (2.5–50 cm) and wet tissues were deposited. We found that for all plastic categories and for all riverbanks averaged, the plastic accumulation rate during the July 2021 flood was higher than that which would be expected for that time of year. However, the average accumulation rate for all locations during the period that included the flood was lower than the average accumulation rate over the Dutch winter (Oct/Nov–Feb/Mar). Our results show that litter category composition following the July 2021 flood differed from normal conditions. This indicates that plastic deposition and remobilization processes on riverbanks differ between extreme flood and annually average conditions. These observations contribute to a better understanding of the fate of macroplastic in the environment in terms of the drivers of both its transport and deposition.

The enriched Thomason model structure on 2-categories

We prove that categories enriched in the Thomason model structure admit a model structure that is Quillen equivalent to the Bergner model structure on simplicial categories, providing a new model for (∞,1)-categories. Along the way, we construct model structures on modules and monoids in the Thomason model structure and prove that any model structure on the category of small categories that has the same weak equivalences as the Thomason model structure is not a cartesian model structure. This paper is also available as arXiv:2208.02954v4.

Algebras of reduced E-Fountain semigroups and the generalized ample identity II

We study the generalized right ample identity, introduced by the author in a previous paper. Let [Formula: see text] be a reduced [Formula: see text]-Fountain semigroup which satisfies the congruence condition. We can associate with [Formula: see text] a small category [Formula: see text] whose set of objects is identified with the set [Formula: see text] of idempotents and its morphisms correspond to elements of [Formula: see text]. We prove that [Formula: see text] satisfies the generalized right ample identity if and only if every element of [Formula: see text] induces a homomorphism of left [Formula: see text]-actions between certain classes of generalized Green’s relations. In this case, we interpret the associated category [Formula: see text] as a discrete form of a Peirce decomposition of the semigroup algebra. We also give some natural examples of semigroups satisfying this identity.

Evaluation of body weight and morphometric characteristics of the young queen of Apis cerana javana at different queen cup cell sizes

Abstract. Masyithoh D, Kentjonowaty I, Salleh SM, Ustadi, Agussalim, Nastain FS. 2023. Evaluation of body weight and morphometric characteristics of the young queen of Apis cerana javana at different queen cup cell sizes. Biodiversitas 24: 5626-5633. This study investigates body weight and morphometric characteristics of Apis cerana javana queen rearing based on differences in the queen cup sizes. The queen cell sizes were divided into three categories; the first group was a small category (T1) with a height of 0.75 cm, top diameter of 0.65 cm, and bottom diameter of 0.44 cm. The second treatment was medium category (T2) with a height of 0.85 cm, a top diameter of 0.71 cm, and a bottom diameter of 0.54 cm. The third treatment was a large category (T3) with a height of 1.00 cm, a top diameter of 0.71 cm, and a bottom diameter of 0.62 cm. The morphometrics investigated consisted of hatch weight, pupae length, body length, head, abdomen, wing, and hind leg morphometrics. The results showed that the differences in the queen cup size had no effect (P&gt;0.05) on the hatch weight, body length, width, and length of the head, thorax, fore and hind wing (length and width), and abdomen (length and height). The different queen cell sizes did not affect the wing morphometrics (P&gt;0.05). In addition, the leg morphometrics consisting of femur, tibia, tarsus, and metatarsus were also not affected (P&gt;0.05) by the different queen cup sizes. These results revealed that the different queen cup sizes did not negatively impact the morphometric characteristics of A. cerana javana queen’s.

SSLpheno: a self-supervised learning approach for gene-phenotype association prediction using protein-protein interactions and gene ontology data.

Medical genomics faces significant challenges in interpreting disease phenotype and genetic heterogeneity. Despite the establishment of standardized disease phenotype databases, computational methods for predicting gene-phenotype associations still suffer from imbalanced category distribution and a lack of labeled data in small categories. To address the problem of labeled-data scarcity, we propose a self-supervised learning strategy for gene-phenotype association prediction, called SSLpheno. Our approach utilizes an attributed network that integrates protein-protein interactions and gene ontology data. We apply a Laplacian-based filter to ensure feature smoothness and use self-supervised training to optimize node feature representation. Specifically, we calculate the cosine similarity of feature vectors and select positive and negative sample nodes for reconstruction training labels. We employ a deep neural network for multi-label classification of phenotypes in the downstream task. Our experimental results demonstrate that SSLpheno outperforms state-of-the-art methods, especially in categories with fewer annotations. Moreover, our case studies illustrate the potential of SSLpheno as an effective prescreening tool for gene-phenotype association identification. https://github.com/bixuehua/SSLpheno.

Analysis of the Marketing Status of Insecticide Brands and Buying Behavior of Chilli Growers in Rajkot District, Gujarat, India

The present study was undertaken in Gondal, Jamkandorna, Upleta and Dhoraji talukas of Rajkot district, as all four talukas have higher areas under chilli cultivation. A total of 120 chilli growers and 20 insecticide dealers were selected with the help of a multistage sampling method. The study was mainly based on primary data, which were collected through personal interviews with the help of a well-structured survey schedule. The results showed that the highest percentage of chilli growers belonged to middle age group and had higher secondary education. The majority of the chilli growers belonged to small and semi-medium land-holding categories and had annual incomes between ₹2,59,036 to ₹5,91,582. Near about two-thirds (66.67 %) of chilli growers belonged to the nuclear family. The majority (37.50%) of the chilli growers were found engaged in farming with business as their occupation and the majority of chilli growers had farming experience of more than 15 years. Bore wells (56.87%) were reported as the main source of irrigation in the study area. The study also revealed that the highest market share was captured by Nagarjuna Agrichem Limited company followed by Bayer Crop Science and United Insecticides Pvt. Ltd. company. With regard to the mode of purchase of insecticides most of 40.00 per cent of the chilli growers used to purchase insecticides on a credit basis. So, companies should define and ease the conditions for credit availability, to make it convenient and affordable for both farmers and dealers. Most of the chilli growers were buying insecticides from retailer’s shops. The majority (45.83%) of chilli growers preferred to use the same brand with the same quantity when prices of selected insecticides changed (increased) and in the absence of the required insecticide brand; most (85.83%) chilli growers shifted to other insecticide brands. The insecticide companies should make the product available in the market as per the season and demand because if the grower will not get the desired product at the right time, they may switch to an alternative product.

Surrounded by Giants: Habitable Zone Stability Within the HD 141399 System

The search for exoplanets has revealed a diversity of planetary system architectures, the vast majority of which diverge significantly from the template of the solar system. In particular, giant planets beyond the snow line are relatively rare, especially for low-mass stars, placing the solar system within a small category of systems with multiple giant planets at large separations. An exoplanetary system of note is that of HD 141399, consisting of a K-dwarf host star that harbors four giant planets with separations extending to ∼4.5 au. The architecture of the system creates a complex pattern of mean motion resonances and gravitationally perturbed regions that may exclude the presence of other planets, including within the habitable zone of the system. Here, we present the results of dynamical simulations that explore the interaction of the known planets of the system, their apsidal trajectories, resonance locations, and dynamical evolution. We further investigate the results of injecting Earth-mass planets and provide the regions of dynamical viability within the habitable zone where terrestrial planets may maintain long-term stability. We discuss these results in the context of the importance of giant planets for volatile delivery and planetary habitability considerations.

The twisted tensor product of dg categories and a contractible 2-operad

It is well-known that the “pre-2-category” Catdgcoh(k) of small dg categories over a field k, with 1-morphisms defined as dg functors, and 2-morphisms defined as the complexes of coherent natural transformations, fails to be a strict 2-category. The question “What do dg categories form?”, raised by V. Drinfeld in [14], is interpreted in this context as a question of finding a weak 2-category structure on Catdgcoh(k). In [32], D. Tamarkin proposed an answer to this question, by constructing a contractible 2-operad in the sense of M. Batanin [3], acting on Catdgcoh(k).In this paper, we construct another contractible 2-operad, acting on Catdgcoh(k). Our main tool is the twisted tensor product of small dg categories, introduced in [25]. We establish a one-side associativity for the twisted tensor product, making (Catdgcoh(k),⊗∼) a skew monoidal category in the sense of [30], and construct a twisted compositionCohdg(D,E)⊗∼Cohdg(C,D)→Cohdg(C,E), and prove some compatibility between these two structures. Taken together, the two structures give rise to a 2-operad O, acting on Catdgcoh(k). Its contractibility is a consequence of a general result of [25].