Sexual Dimorphism in Physiological Reactions to Biotope Type (the Case Study in Ground Beetles)

*Eugeniy Khomitskiy, Tamara Avtaeva, Shapaat Kushalieva, Alexandr Zamotajlov, Rifgat Shagidullin and Raisa Sukhodolskaya*

## **Abstract**

Sexual size dimorphism (SSD) (the difference between males and females in size) is considered to be the physiological reaction to environmental conditions. We estimated body size variation and SSD in two populations of ground beetle *Carabus exaratus*. Beetles were sampled in Krasnodar Province (Russia) in the forb-cereal meadow and beech-hornbeam forest. We processed morphometric measurements in 521 specimen for six linear traits. Beetles from the meadow were slightly larger than from the forest. SSD was pronounced in a half of traits being the highest by elytra length. On a whole, SSD did not differ in the populations studied.

**Keywords:** sexual size dimorphism, ground beetles, body size variation, physiological reaction, stress

## **1. Introduction**

A lot of studies deal with the relationships between the sizes of different parts or entire bodies of organisms. They investigate how such body size variation affects different morphologies and important functions, that is, physical strength, metabolic rates, and transport of resources [1]. Such size patterns can be studied both within individuals and species and across species of plant or animal. Male and female insects often differ morphometrically, by size [2]. Females are usually larger than males, while males demonstrate lower phenotypic plasticity [3, 4]. Phenotypic plasticity is induced by ecological and environmental variables.

The aim of our study was to top up the knowledge in sexual size dimorphism (SSD) in insects, specifically in ground beetles. The former studies showed SSD variability in these beetles depending on environmental conditions. We chose Caucasian species 0 *Carabus exaratus* Quencel, which was not sufficiently investigated. So we hypothesized that: (i) SSD in it is female-biased; (ii) the beetles from different

biotopes will differ in body size; and (iii) SSD by different traits will vary and will be the highest by elytra width.


**4. Strategies for improving oil content by modifying triacylglycerol metabolism in oil seed crops**

Since plant oils are commercially important, improving oil seed crops has long been a focus of breeders. Such breeding efforts, which began in ancient times, have led to the improvement of oil contents in several crops. In addition, the oil contents of the seeds of modern cultivars are significantly higher than those of wild species [23, 24]. Currently, many plant breeders have undertaken the challenge of further increasing seed oil contents. However, recent studies using quantitative trait loci analyses revealed that seed oil contents are controlled by many genes with additive effects [25–28], suggesting that traditional breeding methods based on cross-fertilization may be inadequate for further increasing seed oil contents.

**Figure 4.** Seeds of *Arabidopsis thaliana*. (A) Microscopic image of Arabidopsis seeds. (B) Electron microscopic image of Arabidopsis seed cells. OB: oil body, an oil storage organelle in seeds. PB: protein body, an organelle that accumulates seed storage protein.

By contrast, genetic transformation may be an effective tool for increasing seed oil contents. The model plant *Arabidopsis thaliana*, a close relative of the major oil crop *Brassica napus*, produces typical oil seeds (**Figure 4A** and **B**). The use of Arabidopsis drastically simplifies both the processes of screening mutants with abnormal phenotypes and generating transformants, in which genes of interest are introduced. The use of Arabidopsis has accelerated the process of uncovering TAG metabolic pathways in plants. In fact, most genes encoding enzymes involved in TAG metabolism have been identified based on characterization of Arabidopsis mutants defective in TAG metabolism [29, 30]. Elucidating TAG metabolic pathways has revealed the limiting factors and key enzymes in this process and has led to the development of novel strategies for improving seed TAG contents. In this section, we review important strategies for improving TAG contents in seeds based on metabolic engineering approaches.

#### **4.1. Enhancement of TAG biosynthesis**

addition to the *de novo* synthesis pathway, TAG is produced via an alternative pathway through phosphatidylcholine (hereafter referred to as PC) [15, 16]. PC, one of the main components of membrane lipids, is present in pools in the ER [16]. PC pools affect *de novo* TAG synthesis and the acyl-CoA pool in the cytosol to supply DAG as a precursor for TAG [16].

142 New Challenges in Seed Biology - Basic and Translational Research Driving Seed Technology

**Figure 3.** Triacylglycerol formation in the ER: (1) acyl-CoA:G3P acyltransferase, (2) acyl-CoA:LPA acyltransferase, (3)

Synthesized TAGs accumulate in compartments in the ER (**Figure 1C**), which are converted to vesicles through budding. The vesicles then develop into oil-accumulating organelles, i.e., oil bodies [16–19]. Oil bodies are TAG storage organelles with a single layer membrane, whose major membrane protein is oleosin [18, 20, 21]. Oleosin blocks adhesion between neighboring oil bodies, which allows small oil bodies to be packed tightly together without adhesion in the

**4. Strategies for improving oil content by modifying triacylglycerol**

Since plant oils are commercially important, improving oil seed crops has long been a focus of breeders. Such breeding efforts, which began in ancient times, have led to the improvement of oil contents in several crops. In addition, the oil contents of the seeds of modern cultivars are significantly higher than those of wild species [23, 24]. Currently, many plant breeders have undertaken the challenge of further increasing seed oil contents. However, recent studies using quantitative trait loci analyses revealed that seed oil contents are controlled by many

PA phosphatase, and (4) acyl-CoA:DAG acyltransferase.

**3.4. Triacylglycerol accumulation**

**metabolism in oil seed crops**

cells of oil seeds [22].

The TAG biosynthetic pathway, which extends across plastids, the cytosol, and the ER, involves many enzymes [30]. Additionally, DAG biosynthetic pathways include the *de novo* synthetic pathway and the phosphatidylcholine-derived pathway (hereafter referred to as PCderived pathway), whose activities greatly differ among plant species [15, 16]. Thus, increasing the activity of enzymes in the *de novo* or PC-derived pathway does not always increase seed oil contents in every plant species. On the other hand, TAG production from DAG by acyl-CoA:DAG acyltransferase is a common pathway among plants. Overexpressing acyl-CoA:DAG acyltransferase significantly increases seed TAG contents in Arabidopsis [31] and in other plants species [32–37]. These findings indicate that the conversion of DAG to TAG is one of the rate-limiting steps in the production of TAG in seeds, and they suggest that the acyl-CoA:DAG acyltransferase gene would be a promising target gene for increasing TAG contents.

#### **4.2. Suppression of TAG degradation**

Synthesized TAG is stored in oil bodies and degraded during germinative growth [17, 38, 39]. The TAG degradation pathway has also been uncovered, and most genes encoding enzymes in this pathway have been identified [17, 39]. The expression of these genes is upregulated after seed imbibition, and TAG degradation activity rapidly increases in imbibed seeds [40– 42]. These genes are also expressed during seed development in several plants [43, 44]. In fact, TAG degradation occurs in developing seeds [45–47]. Therefore, the TAG degradation pathway is activated during seed development, and seeds lose some of the TAG synthesized during seed development. This finding suggests that suppressing TAG degradation would be a promising strategy for improving seed oil contents. Oil degradation begins with TAG hydrolysis via TAG lipase. TAG lipase was genetically identified as *SUGAR DEPENDENT 1* in Arabidopsis [48] and was subsequently identified in rapeseed and Jatropha [47, 49]. Suppressing *SUGAR DEPENDENT 1* expression significantly increases seed oil contents [47, 49]. These reports indicate that suppressing TAG degradation via suppressing *SUGAR DEPENDENT 1* expression may represent an effective strategy for increasing seed oil contents in oil seed crops.


**6.1 Key factors affecting induced seismicity**

As shown in **Figure 11** [54], the mechanism for inducing seismicity appears to be well known, that is, weakening pre-existing faults by increasing fluid pressure. The formation will release stored elastic strain energy when a fault slips, triggering seismicity. The fault will remain locked as long as the applied shear stress is less than the

**Figure 11.** *Schematic diagram of mechanisms for inducing seismicity [54].*

strength of the contact. The failure condition can be determined according to the effective stress principle and the Mohr-Coulomb criterion.

Theoretically, the increase of fluid pressure should be the direct reason for induced seismicity and it can be avoided by changing the injection rate and controlling the formation pressure to avoid induced seismicity. Based on the mechanism of induced seismicity, the possible reasons for seismic events caused by GCS are clarified [57–59].


**Author details**

Lucielen Oliveira Santos\*, Pedro Garcia Pereira Silva, Sharlene Silva Costa and Taiele Blumberg Machado Laboratory of Biotechnology, School of Chemistry and Food, Federal University of Rio Grande, Rio Grande, RS, Brazil

\*Address all correspondence to<EMAIL_ADDRESS>
© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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*Magnetic Field Application to Increase Yield of Microalgal Biomass in Biofuel Production DOI: http://dx.doi.org/10.5772/intechopen.94576*


**2. An overview of the global denim market**

Denim is a type of sturdy cotton twill woven fabric with a characteristically diagonal ribbing known for its use in the form of jeans and other clothing all across the world. Originally used for workers' clothes, denim has entered the world of high fashion for a long time, and this has urged the industry to produce innovative denim with different fibers including lyocell, bamboo, viscose, rayon, polyethylene terephthalate, and elastane. Also, several types of washes have been introduced, such as stonewash and stoneless wash, acid wash, moon wash, monkey wash, and enzymes which have been used because of their environmental-friendly nature in comparison with hypochlorite and pumice stones [2].

Rising casualization of clothing all over the world, together with the availability of high-quality, cost-effective denim products, has contributed to the growth of the market over the years. E-commerce is the other factor which has a positive influence on the denim market's growth. In addition, brands have started to reinforce their commitments to responsible production efforts and launched more sustainable collections to the market, which has dramatically increased new retail products described as "sustainable" since 2017. Orta Anadolu, for example, introduced its organic cotton production of denim fabrics in 2006 and a capsule collection without virgin cotton in 2018. Similarly, Diesel launched a sustainable capsule collection with Coca-Cola [3].

The global denim market is segmented into North America (NA), Europe (EU), Asia-Pacific (APAC), the Middle East and Africa (MEA), and South America (SA). The major companies operating in the global denim market are Levi Strauss & Co., VF Corporation (with renowned brand names of Lee and Wrangler), Diesel SpA, Gap Inc., Hennes & Mauritz AB, Inditex, and PVH Corp., and Tommy Hilfiger Licensing LLC. The jean market is a highly fragmented market, with a strong presence of local and global players operating all over the world. Thus, to sustain their positions in the market, the active players are bringing innovation in their product offering, in order to cater to changing consumers' fashion lifestyle [4].

Also, they have been focusing on social media platforms as well as online distribution channels for their marketing and branding activities so as to attract more customers. Denim manufacturers, however, appear to focus on acquisitions, expansions, and collaborations with mostly startup companies to gain a significant market share [2–3].

## *Understanding Denim Recycling: A Quantitative Study with Lifecycle Assessment Methodology DOI: http://dx.doi.org/10.5772/intechopen.92793*

In 2019, the global denim market was valued at approximately 90 billion US dollars and is expected to reach a value of around 107 billion US dollars by 2023 [5]. The global denim jean market size, on the other hand, was valued at USD 64.62 billion in 2018, and it is estimated to expand further at a compound annual growth rate (CAGR) of 6.81% from 2019 to 2025 [6]. The Asia-Pacific region led the market in 2019, which was followed by North America, Europe, South America, and the Middle East as a response to the introduction of global brands and an emphasis on premium denim. Japan, China and India are expected to lead the region through 2024 as a result of the countries' rise in promotional activities within the denim market [2, 4].

According to the World Denim Fabric Foreign Trade Report published by the Istanbul Textile and Raw Materials Exporters Association (ITHIB), global denim fabric exports increased by 5.1% in 2018 and reached approximately 5 billion US dollars. The top five countries performing most denim exports are China (42% share of total exports), Pakistan (11.7% share of total exports), India (8.2% share of total exports), Hong Kong (7.4% share of total exports), and Turkey (6.8% share of total exports). It is stated that there is a strong growth in the denim production in Bangladesh and Vietnam, although these countries are mostly importing denim fabric [7].

Europe, the United States, and Japan are the biggest consumers of denim, whereas China and India, being relatively younger economies, are witnessing a steady rise in demand for denim. In 2018, men's wear segment accounted for the largest market share of more than 55%. It is forecasted that the segment will retain its leading position over the upcoming years mainly because of the improved standards of living and demand for trendy fashion apparels. Women's wear segment is, on the other hand, expected to register the fastest compound annual growth rate (CAGR) of 7.25% from 2019 to 2025. This growth is attributed to the high product demand, especially in emerging countries. In addition to that, constant product innovation in this segment is also expected to drive the growth further [2, 6].

#### **2.1 Environmental impacts of denim processing**

It is estimated that producing a pair of jeans consumes around 2900 liters of water and large amounts of chemicals and energy. If this is multiplied by the number of jeans produced globally, one can get an idea of the enormous contribution of wastewater and harmful gases by denim industry to the environment [8, 9].

Indigo dye is one of the organic colorants used to color textiles, paper, leather, and plastic and for many applications such as cosmetic and photochemical production. Unfortunately, textile effluents containing indigo dye and other dye types make water toxic and harmful for human and animal consumption, which causes an imbalance in different aquatic ecosystem food chains [10]. The use of synthetic indigo and sulfur dyes also presents serious effluent problem. Bearing in mind that majority of warp dyeing for denim uses indigo and sulfur dyes, the environmental impacts of denim processing can be classified into three main categories:

As is well-known, denim washing is imparted to fabric to improve the softness, comfort, and most importantly achieving a variety of looks such as a faded or

designs are monomaterials, elimination of toxic substances, modular manufacturing for ease of removal or exchange, easily compatible materials, and labels or codes

The environmental impact of denim products, during manufacture, use, or disposal, can be evaluated by looking at the different phases of the product's life cycle and taking action at the phases where it will be most effective to reduce the impact. However, the lifecycle of a product is long and complicated, covering many areas with many people involved in each phase [1]. There is a variety of voluntary and mandatory tools which help achieve this objective. These include economic instruments, bans on certain substances, environmental labeling, voluntary agreements, product design guidelines, etc. Life cycle assessment (LCA) methodology is one of the aforementioned tools, and within the frame of this chapter, it is adopted to quantify and compare the environmental impact of recycled denim fabrics. But

before that, the global denim market, environmental impacts of denim

textiles and apparel today are also discussed in this chapter.

**2. An overview of the global denim market**

son with hypochlorite and pumice stones [2].

with Coca-Cola [3].

market share [2–3].

**60**

manufacturing, sources of denim waste, and recycling processes currently used in

Denim is a type of sturdy cotton twill woven fabric with a characteristically diagonal ribbing known for its use in the form of jeans and other clothing all across the world. Originally used for workers' clothes, denim has entered the world of high fashion for a long time, and this has urged the industry to produce innovative denim with different fibers including lyocell, bamboo, viscose, rayon, polyethylene terephthalate, and elastane. Also, several types of washes have been introduced, such as stonewash and stoneless wash, acid wash, moon wash, monkey wash, and enzymes which have been used because of their environmental-friendly nature in compari-

Rising casualization of clothing all over the world, together with the availability of high-quality, cost-effective denim products, has contributed to the growth of the market over the years. E-commerce is the other factor which has a positive influence on the denim market's growth. In addition, brands have started to reinforce their commitments to responsible production efforts and launched more sustainable collections to the market, which has dramatically increased new retail products described as "sustainable" since 2017. Orta Anadolu, for example, introduced its organic cotton production of denim fabrics in 2006 and a capsule collection without virgin cotton in 2018. Similarly, Diesel launched a sustainable capsule collection

The global denim market is segmented into North America (NA), Europe (EU), Asia-Pacific (APAC), the Middle East and Africa (MEA), and South America (SA). The major companies operating in the global denim market are Levi Strauss & Co., VF Corporation (with renowned brand names of Lee and Wrangler), Diesel SpA, Gap Inc., Hennes & Mauritz AB, Inditex, and PVH Corp., and Tommy Hilfiger Licensing LLC. The jean market is a highly fragmented market, with a strong presence of local and global players operating all over the world. Thus, to sustain their positions in the market, the active players are bringing innovation in their product offering, in order to cater to changing consumers' fashion lifestyle [4]. Also, they have been focusing on social media platforms as well as online distribution channels for their marketing and branding activities so as to attract more customers. Denim manufacturers, however, appear to focus on acquisitions, expansions, and collaborations with mostly startup companies to gain a significant

that can be recycled.

*Waste in Textile and Leather Sectors*

worn-out appearance. Pumice stone is used to stonewash denim garments. The stone gets abraded during the process and becomes powdered; part of it remains in the liquor, and part of it sticks to the garment. A sizeable amount of water is required for repeated washing cycles to remove the deposited pumice from the denim. The effluent and pumice dust lead to environmental pollution. Sandblasting is a mechanical finish which uses sand containing silica. The minute silica dust spreads in air, it poses serious respiratory disease such as silicosis [10].

material. The remaining 20% of the clothes are either sold on the second-hand

*Understanding Denim Recycling: A Quantitative Study with Lifecycle Assessment Methodology*

As one of the sources of solid waste, the cutting waste during denim jean production—which has relatively a homogeneous nature—is between 10% and 15%, and most of the waste is recycled by unraveling and reusing the fibers in the production of insert yarns (weft direction), which is a good example of "recycling

Another source of denim waste is the post-consumer denim jeans. Color, quality of fabric, and garment accessories like rivets, buttons, zippers, and labels are the main components of the heterogeneous nature of this very denim waste. The main problem is the collection of post-consumer jeans. Although in many countries collection systems are in place, many consumers discard their jeans as solid municipal waste. Jeans that are collected are mostly sold to textile sorting companies which manually/automatically sort the rewearable jeans for sale to second-hand shops and in Third World countries. Nonwearable jeans are, however, shredded and used for the development of various types of products such as thermal and acoustic insulators and/or textile-based composites for certain structural and other special-

Finally, as a different approach to decreasing the denim waste regarding postconsumer denim jeans, the leasing of jeans was introduced several years ago by MUD Jeans. In this concept, the producer or distributor of the jeans stays the owner. The user of the jeans only "buys" the right to the use the jeans for a period of 1 year. If the jeans need to be repaired, it is at the cost of the lease company [22]. The same company, together with several of others, has also focused on "design for recycling (D4R)" for facilitating the recycling of denim jeans, such that they do not use leather labels but printed ones at the waistband, employ rivets and buttons that are made from 100% stainless steel and no finishing (electroplating), and have utilized buttons made out of recycled jeans on their denim shirts and sweaters, etc.

An average person buys 60% more clothing items every year and keeps them for

half as long as they used to keep about 15 years ago. It is assumed that overall consumption of textiles will have reached to 102 million tons by 2030 and that the textile industry's waste will have increased by about 60% between 2015 and 2030. That means the total level of fashion waste will reach to 148 million tons in 2030. As is known, the majority of clothing waste ends up in landfills or is incinerated, and once in landfills, it takes hundreds of years for natural fibers to decompose and may release methane and CO2 into the atmosphere. Synthetic materials, on the other

**3. An overview of recycling in textiles and apparel**

in design (RiD)." Most jeans' producers recycle denim waste in their own manufacturing plants or have contracts with textile waste recyclers to reuse the waste material in the spinning of new yarns. There is also substantial trade of denim

Being the largest fraction of apparel, waste jeans (or waste denim fabric from tailoring operations) are composed mainly of "cotton" and "cotton/polyester" fabric with different weight ratios [19]. Although this may lead to the understanding that denim made with 100% cotton, in particular, will readily deteriorate in the environment, in practice a pair of such jeans can stay alive in the environment for a very long time, and therefore the negative environmental impact is very high. The literature reveals that the amount of waste jeans generated annually is estimated as 2.16 million tons and only 35–50% of this amount is collected in Western Europe in

market within the EU or is sent to landfill or incineration [18].

order to reuse or recycle it after sorting [13, 20–21].

 In the case of chemical washing involving the use of sodium hypochlorite or potassium permanganate, the effluent contains chlorinated organic substances which cause severe impacts to the environment, and the bleaching chemicals are harmful to human health. Acid wash uses both pumice stone and chemicals, namely, sodium hypochlorite or potassium permanganate, and it does not require water but leads to pollution through the effluent having pumice dust and residual manganese which are hazardous [11–12].

Despite all these setbacks of the denim processes summarized above, various suitable treatment processes have been developed and employed for the dyeing effluent on the basis of the nature and complexity of the dyes and chemicals present in denim. Fortunately, many denim companies and their suppliers have been striving hard to embrace greener methods such as laser processing and nano bubble ozone washing machines and are also making effort to develop new techniques of producing jeans, as a part of their business strategies to preserve the environment. They have also understood the importance and the need to build a sustainable business [12–14].

#### **2.2 Sources of denim waste**

It is considered that sustainable material management is a precursor of circular economy, which promotes recycling, reuse, and remanufacturing. It was estimated that around 65 billion tons of raw materials were processed by the industrial system at the end of the first decade of the twenty-first century, and this quantity is expected to reach about 82 billion tons by the end of 2020. Therefore, in the last two decades, circular economy (CE) is gaining growing global consideration as the new development model which is capable of influencing the existing production and consumption model [15]. Within that concept, waste is classified on the basis of generation as pre-consumer textile waste, post-consumer textile waste, and industrial textile waste. Pre-consumer waste is the remaining production processes in the industry which includes raw material to finished products ready for market. This may include offcuts, shearing, selvedges, b-grade garments, export surplus, etc. which are homogenous and clean in nature to be used for other purposes. The waste under this class has great potential for reuse and recycling. The post-consumer textile waste can include any product that has completed its life cycle and is no longer useful to the consumer in both function and esthetics. Industrial textile waste is, however, the result of the manufacturing processes and is termed as dirty waste [13, 16].

The textile and apparel industry, which generates a substantial environmental footprint from cultivation, fabric and garment manufacturing, to the landfill disposal of post-consumer items, faces tremendous environmental and resource challenges [17]. In order to tackle such challenges to some extent, several fashion companies offer their customers to take care of their worn-out clothes including denim jeans. However, studies have concluded that less than 1% of these collected clothes are being recycled while nearly 80% of them are mainly sold on the secondhand market in poor countries around the world or used as blankets or isolation

### *Understanding Denim Recycling: A Quantitative Study with Lifecycle Assessment Methodology DOI: http://dx.doi.org/10.5772/intechopen.92793*

material. The remaining 20% of the clothes are either sold on the second-hand market within the EU or is sent to landfill or incineration [18].

Being the largest fraction of apparel, waste jeans (or waste denim fabric from tailoring operations) are composed mainly of "cotton" and "cotton/polyester" fabric with different weight ratios [19]. Although this may lead to the understanding that denim made with 100% cotton, in particular, will readily deteriorate in the environment, in practice a pair of such jeans can stay alive in the environment for a very long time, and therefore the negative environmental impact is very high. The literature reveals that the amount of waste jeans generated annually is estimated as 2.16 million tons and only 35–50% of this amount is collected in Western Europe in order to reuse or recycle it after sorting [13, 20–21].

As one of the sources of solid waste, the cutting waste during denim jean production—which has relatively a homogeneous nature—is between 10% and 15%, and most of the waste is recycled by unraveling and reusing the fibers in the production of insert yarns (weft direction), which is a good example of "recycling in design (RiD)." Most jeans' producers recycle denim waste in their own manufacturing plants or have contracts with textile waste recyclers to reuse the waste material in the spinning of new yarns. There is also substantial trade of denim waste all over the world [13, 21–22].

Another source of denim waste is the post-consumer denim jeans. Color, quality of fabric, and garment accessories like rivets, buttons, zippers, and labels are the main components of the heterogeneous nature of this very denim waste. The main problem is the collection of post-consumer jeans. Although in many countries collection systems are in place, many consumers discard their jeans as solid municipal waste. Jeans that are collected are mostly sold to textile sorting companies which manually/automatically sort the rewearable jeans for sale to second-hand shops and in Third World countries. Nonwearable jeans are, however, shredded and used for the development of various types of products such as thermal and acoustic insulators and/or textile-based composites for certain structural and other specialized applications [13, 21, 23–28].

Finally, as a different approach to decreasing the denim waste regarding postconsumer denim jeans, the leasing of jeans was introduced several years ago by MUD Jeans. In this concept, the producer or distributor of the jeans stays the owner. The user of the jeans only "buys" the right to the use the jeans for a period of 1 year. If the jeans need to be repaired, it is at the cost of the lease company [22]. The same company, together with several of others, has also focused on "design for recycling (D4R)" for facilitating the recycling of denim jeans, such that they do not use leather labels but printed ones at the waistband, employ rivets and buttons that are made from 100% stainless steel and no finishing (electroplating), and have utilized buttons made out of recycled jeans on their denim shirts and sweaters, etc. [13, 29–30].