Consider a length-n sequence x over a q-ary alphabet. The fixed-length Levenshtein ball Lt(x) of radius t contains all length-n q-ary sequences that can be derived from x by performing t deletions followed by t insertions. Recent studies have successfully characterized fixed-length Levenshtein balls in the context of radius t = 1. These works have derived explicit formulas for various quantities, including the exact size of the balls, extremal bounds (minimum and maximum sizes), as well as expected sizes and their concentration properties. However, the general case involving an arbitrary number of t deletions and t insertions (t > 1) remains largely uninvestigated. This work systematically examines fixed-length Levenshtein balls with multiple deletions and insertions, focusing specifically on fixed-length burst Levenshtein balls, where deletions occur consecutively, as do insertions. We provide solutions for explicit cardinality formulas, extremal bounds (minimum and maximum sizes), expected size, and concentration properties surrounding the expected value.

Low-temperature is one of the main natural adversities in tobacco leaf planting. Tobacco is very sensitive to low-temperature. To understand the underlying the response mechanism of tobacco to low-temperature stress, the physiology, biochemistry, transcription and metabolism at the seedling stage under low-temperature stress were investigated. The results showed that compared with the control, the leaves were thinner, wilted and yellow, the chlorophyll content was reduced, and the chloroplasts were damaged to some extent by low-temperature stress. Compared with the control group, a total of 8262 differentially expressed genes (DEGs) were detected in the group under low-temperature stress, of which 4513 were up-regulated and 3749 were down-regulated. GO and KEGG enrichment analyses showed that low-temperature had significant effects on the antioxidant activity, hormone response and photosynthetic pathway of tobacco cells. Furthermore, 560 differentially expressed transcription factors were screened, including AP2/ERF-ERF (60), WRKY (36), bHLH (31), NAC (29), MYB (28), and C2H2 (26) families. There were 110 differentially abundant metabolites detected, of which 62 were up-regulated and 48 down-regulated. The differentially abundant metabolites were mainly concentrated in metabolism and synthesis related pathways, such as carbon metabolism, glucose metabolism, amino acid metabolism and flavonoid synthesis and metabolism. This combined omics analysis revealed that the plant hormone transduction pathway, starch and sucrose metabolism pathway, flavonoid synthesis pathway, photosynthetic pathway and related transcription factor regulatory genes played an important role in the response of tobacco seedlings to low-temperature stress.

Let 𝒜⊆[n] ()a and ℬ⊆[n] ()b be two families of subsets of [n], we say 𝒜 and ℬ are cross-intersecting if A∩ B∅ for all A∈𝒜 , B∈ℬ . In this paper, we study cross-intersecting families in the multi-part setting. By characterizing the independent sets of vertex-transitive graphs and their direct products, we determine the sizes and structures of maximum-sized multi-part cross-intersecting families. This generalizes the results of Hilton’s (J Lond Math Soc 15(2):369–376, 1977) and Frankl–Tohushige’s (J Comb Theory Ser A 61(1):87–97, 1992) on cross-intersecting families in the single-part setting.

Motivated by emerging applications in coding for molecular data storage, much attention has been paid to the intersecting set discrepancy problem, which aims to design a large family of subsets of a common labeled ground set with bounded pairwise intersection and bounded set discrepancy. In this paper, we study the maximum size of such families of $k$ -subsets with $v$ elements ground set, $t$ -bounded intersections, and zero or one discrepancy, called as balanced $(t,k,v)$ set codes. By turning this problem into a graph edge-labeling problem, we are able to determine the maximum size of codes when $k=3,4$ and $t=2,3$ for a given ground set. The constructions are based on combinatorial designs, matching decompositions and edge coloring schemes. Furthermore, we improve the upper bound for balanced $(t,k,v)$ set codes with all integers $2\leq t < k < v$ . By the powerful probabilistic argument–Kahn's Theorem, we show that the improved upper bound for any fixed integers $2 \leq t < k$ is asymptotically tight when $v$ goes to infinity.

Motivated by applications in modern storage devices such as DNA storage and racetrack memories, we study the sequence reconstruction problem which involves two important issues. One is determining the maximum intersection size between two error balls. The other is designing reconstruction codes in which each transmitted sequence can be reconstructed from a given number of noisy reads with redundancy as small as possible. In this paper, we focus on channels that introduce single-burst-insertion/deletion error. We fully determine the maximum intersection size between two burst-insertion/deletion balls for both fixed-length and variable-length models. Then we characterize a pair of sequences when their burst-insertion/deletion balls have intersection of a certain size. Using these characterizations, we design reconstruction codes for all values $N$ of the number of noisy reads and analyze their lower bounds. In addition, we extend our results to the burst-edit channel.

【Objective】Analyzing the key physical and chemical indexes that affects the sensory quality of middle tobacco leaves (C3F grade) in Weifang, which can provide a certain theoretical basis for further improving the sensory quality of tobacco leaves in Weifang tobacco area.【Method】The key phenotypic, sensory and chemical parameters of the middle tobacco leaves of Linqu and Zhucheng from 2019 to 2021 were determined by physical measurement, chemical detection and sensory evaluation.【Result】The sensory evaluation of tobacco in middle leaves of Weifang was good, compared with Linqu tobacco area, the leaf length, leaf width, leaf weight, leaf thickness and leaf surface density of middle leaves in Zhucheng tobacco area was increased by 5.45%, 7.31%, 25.42%, 15.36% and 12.46%, respectively, while the stem content was decreased by 11.32%. The content of reducing sugar, total sugar, starch, nitrogen and chlorine in Zhucheng tobacco was increased by 9.83%, 6.23%, 26.12%, 7.9% and 291% compared to Linqu tobacco area, but the ratio of potassium to potassium chloride was significantly lower than that in Linqu tobacco area. The canonical correlation analysis of sensory quality and chemical indexes of tobacco leaves respectively obtained 1 and 0 pair canonical variables in Linqu and Zhucheng respectively, the results showed that the indexes of sensory quality which have a great influence on the canonical variables in Linqu were impurity, aftertaste and combustibility, and the chemical indexes were two-sugar ratio, chlorine content, potassium-chlorine ratio and total nitrogen content in leaves. The canonical correlation analysis of sensory evaluation and physical indexes of tobacco leaves respectively obtained 1 and 2 pair canonical variables in Linqu and Zhucheng respectively, the results showed that the indexes of sensory quality which have a great influence on the canonical variables of Linqu were aroma amount, gray amount, aftertaste amount and impurity, and the physical index was leaf length. The sensory quality which had great influence on the canonical variables of Zhucheng were combustibility, fragrance and total score, and the physical indexes was single leaf weight, leaf length and leaf width. Further correlation analysis of the above representative indicators showed that the aftertaste of Linqu tobacco leaves was promoted by nicotine content, while was inhibited by sugar-base ratio, miscellaneous gas was inhibited by chlorine content and aroma quantity was inhibited by leaf thickness and leaf surface density. The aroma of Zhucheng tobacco leaves was promoted by leaf density, and the burning ability was inhibited by the increase of leaf length, leaf width and single leaf weight.【Conclusion】The changes of physicochemical indexes of middle tobacco leaves significantly affected its sensory quality in Weifang tobacco area, in which, the representative physical indexes were leaf length, leaf weight and leaf width, the representative chemical indexes were the ratio of two sugars, chlorine, potassium/chlorine ratio and total nitrogen content, and the representative sensory indexes were impurities, aftertaste, combustibility, aroma and gray. In addition, it is suggesting that further increasing the reducing sugar, potassium content and sugar-alkali ratio of middle tobacco leaves in Weifang, and reducing the chlorine content of middle tobacco leaf in Zhucheng.

Recent years, several new types of codes were introduced to provide fault-tolerance and guarantee system reliability in distributed storage systems, among which locally repairable codes (LRCs for short) have played an important role. A linear code is said to have locality r if each of its code symbols can be repaired by accessing at most r other code symbols. For an LRC with length n, dimension k and locality r, its minimum distance d was proved to satisfy the Singleton-like bound d≤ n-k-⌈ k/r⌉+2. Since then, many works have been done for constructing LRCs meeting the Singleton-like bound over small fields. In this paper, we study quaternary LRCs meeting Singleton-like bound through a parity-check matrix approach. Using tools from finite geometry, we provide some new necessary conditions for LRCs being optimal. From this, we prove that there are 27 different classes of parameters for optimal quaternary LRCs. Moreover, for each class, explicit constructions of corresponding optimal quaternary LRCs are presented.

In recent years, several new types of codes were introduced to provide fault-tolerance and guarantee system reliability in distributed storage systems, among which locally repairable codes (LRCs) have played an important role. A linear code is said to have locality $r$ if each of its code symbols can be repaired by accessing at most $r$ other code symbols. For an LRC with length $n$, dimension $k$, and locality $r$, its minimum distance $d$ was proved to satisfy the Singleton-like bound $d\leq~n-k-\lceil~k/r\rceil+2$. Since then, many studies have been done for constructing LRCs meeting the Singleton-like bound over small fields. In this paper, we study quaternary LRCs meeting Singleton-like bound through a parity-check matrix approach, using tools from combinatorial designs and finite geometry. From this, we prove that there are $27$ different classes of parameters for optimal quaternary LRCs. Moreover, for each class, explicit constructions of corresponding optimal quaternary LRCs are presented. In addition, using tools from finite geometry, this paper also introduces a new method to determine the existence of the optimal LRCs.

党的十九大报告指出，要加强和改进思想政治工作。基层烟站作为烟草行业服务烟农的窗口，做好思想政治工作，是推动基层烟站适应新时代发展的关键。文章阐述了基层烟站开展思想政治工作的必要性，分析了基层烟站开展思想政治工作存在的问题，并提出对策。

为提升烟叶种植效益和烟叶质量,本试验结合山东潍坊当地实际,通过烟蒜轮作种植模式与烟麦轮作、常规烟叶种植模式等轮作模式对比,探索烤烟-大蒜轮作在烟叶培育过程中对烟叶产质、整体种植效益的影响,并探索此种模式的运行机制,为烟农在烟田轮作中选择一种有益增收的轮作模式提供较为合理的数据支撑,试验结果表明,烤烟大蒜轮作使整体烟叶的种植效益得到较大提升,烤烟的产值相较常规烤烟种植要高于1.87％,轮作模式综合种植效益要高于烟麦轮作33.22％,对提高烤烟产量和综合种植效益具有明显优势.

Let {(Ai,Bi)}i=1m be a collection of pairs of sets with |Ai|=a and |Bi|=b for 1≤i≤m. Suppose that Ai∩Bj=0̸ if and only if i=j, then by the famous Two Families Theorem of Bollobás, we have the size of this collection m≤a+ba. In this paper, we consider a variant of this problem by requiring {Ai}i=1m to be intersecting additionally. Using exterior algebra method, we prove a weighted Bollobás-type theorem for finite dimensional real vector spaces under these constraints. As a consequence, we obtain a similar theorem for finite sets, which settles a recent conjecture of Gerbner et al. (2020). Moreover, we also determine the unique extremal structure of {(Ai,Bi)}i=1m for the primary case of the theorem for finite sets.

以中烟101为试验材料,在大田条件下,于2018年和2019年连续比较分析了不同蚯蚓肥施用量(750、1500、2250 kg·hm-2)与施肥方式(条施、穴施)对烤烟农艺性状和干物质积累的影响.结果表明,与常规施肥相比,增施蚯蚓肥可以增加烤烟旺长期、平顶期的最大叶面积,提高全株干重.但相同施肥量(1500 kg·hm-2)下,不同蚯蚓肥施用方式对烤烟农艺性状和全株干重无显著影响.

基层党支部是烟草行业党的建设的基本单元，是党全部工作和战斗力的根基，加强党支部标准化规范化建设，是基层党组织发挥政治引领作用的前提。本文阐述了基层党支部标准化规范化建设的重要意义，通过分析党支部建设中存在的问题，提出了党支部标准化规范化建设的创新路径，为更好地发挥党支部的战斗堡垒和党员的先锋模范作用提出了建议。

为明晰潍坊烟叶水溶性糖组成状况及其对烟叶感官品质的影响,本研究利用离子色谱法对潍坊烟叶水溶性糖进行检测.结果表明,烟叶水溶性糖中,葡萄糖含量最高,占总糖比例在30％以上;果糖含量次之;其次为蔗糖;麦芽糖、鼠李糖和木糖含量较低,三者合占1.00％左右.其中,木糖含量最低,平均为0.02％,而80％的样品中木糖无法准确定量.烟叶中水溶性糖与烟叶感官品质之间存在一定的相关性.葡萄糖、果糖、蔗糖、6种水溶性糖总量、还原糖以及葡萄糖、果糖、麦芽糖3种糖总量对烟叶感官品质有一定促进作用,达到显著甚至极显著水平,麦芽糖对烟叶感官品质不利.

Ever since the famous Erdős-Ko-Rado theorem initiated the study of intersecting families of subsets, extremal problems regarding intersecting properties of families of various combinatorial objects have been extensively investigated. Among them, studies about families of subsets, vector spaces and permutations are of particular concerns. Recently, the authors proposed a new quantitative intersection problem for families of subsets: For $\mathcal{F}\subseteq {[n]\choose k}$, define its \emph{total intersection number} as $\mathcal{I}(\mathcal{F})=\sum_{F_1,F_2\in \mathcal{F}}|F_1\cap F_2|$. Then, what is the structure of $\mathcal{F}$ when it has the maximal total intersection number among all families in ${[n]\choose k}$ with the same family size? In \cite{KG2020}, the authors studied this problem and characterized extremal structures of families maximizing the total intersection number of given sizes. In this paper, we consider the analogues of this problem for families of vector spaces and permutations. For certain ranges of family size, we provide structural characterizations for both families of subspaces and families of permutations having maximal total intersection numbers. To some extent, these results determine the unique structure of the optimal family for some certain values of $|\mathcal{F}|$ and characterize the relation between having maximal total intersection number and being intersecting. Besides, we also show several upper bounds on the total intersection numbers for both families of subspaces and families of permutations of given sizes.

研究烤烟幼苗移栽后不同揭膜时间对烤烟根系生长、 品质及土壤氯离子含量的影响.结果表明,30 d揭膜处理可获得更好的地上部分干物质重,根系活力增加,利于产量的形成,土壤氯离子含量更低,烤烟内在化学成分更协调,烤后烟叶钾离子含量增加,氯离子和烟碱含量减少.揭膜时间越延迟,上述效果表现的越不明显.

为了探究烟叶自然醇化过程中类胡萝卜素降解产物含量变化,科学指导烟叶醇化工作,本研究利用气质联用仪对醇化烟叶进行检测.结果表明,醇化过程中,不同部位烟叶类胡萝卜素降解产物含量变化趋势一致,在醇化0～12个月,总量呈上升趋势,期间上部叶极显著增加32.3％,中部叶显著增加25.6％;醇化12个月之后含量呈波动上升趋势,在36个月时含量达到最大值,上、中部叶含量分别为87.48、71.38μg·g-1.随着醇化进度的增加,巨豆三烯酮、氧化异佛尔酮-2等含量逐渐升高,β-紫罗兰酮、β-环柠檬醛等含量逐渐降低,β-大马酮、金合欢基丙酮A等含量无显著变化.类胡萝卜素降解产物中金合欢基丙酮A、β-大马酮对香气质有显著的有利影响,巨豆三烯酮类物质、香叶醇、二氢猕猴桃内酯对刺激性指标有显著的有利影响;β-环柠檬醛、β-二氢大马酮、香叶基丙酮对烟叶感官质量有着显著的不利作用.

烤后烟叶表面存在大量微生物,研究表明,微生物对烟叶品质的提升有着重要影响.本文分析了烟叶陈化期间品质变化及机理,综述了烟叶表面微生物种类及动态变化,并就微生物在改良烟叶品质方面的应用展开讨论,以期为烟草行业提质增效、降焦减害提供参考.

当前,随着烟草行业发展从高速增长阶段进入到高质量发展的新阶段,迫切需要通过科技创新推动企业高质量发展.本文从创新根基、创新机制、创新人才、创新供给、创新生态五个方面进行研究,就创新驱动烟草企业高质量发展提出几点策略,以期提供借鉴价值.

为进一步提高潍坊烤烟上部叶的工业可用性,研究了赤霉素不同施用浓度及不同施用时间对提高上部烟叶质量的试验研究.结果表明,赤霉素处理上部叶能明显提升其可用性,667 m2最佳施用量为200 mg,施用浓度为10 mg·L-1,于烟株打顶后当天对上部4～6片叶正面一次性喷施,施用10 mg·L-1赤霉素处理的上部叶化学质量得分为90.97,明显高于清水对照得分84.75.