LIFE CYCLE OF ERGOT PDF



Life Cycle Of Ergot Pdf

15.19A Ergot Poisoning Biology LibreTexts. An analysis of ergot alkaloids in the Clavicipitaceae (Hypocreales, Ascomycota) and ecological implications Article (PDF Available) in Symbiosis 46(1) В· January 2008 with 527 Reads, T hree important fungal leaf spot diseases, tan spot, Septoria/Stagonospora nodorum blotch (SNB) and Septoria tritici blotch (STB), commonly occur (often as a complex) in North Dakota and have the potential to reduce test weight and yield by 50 percent. Among these, tan spot is the most common leaf spot disease found in all wheat classes throughout North Dakota..

ergot Definition Symptoms & Ergotism Britannica

A CHEMICAL INVESTIGATION OF ERGOT OF RYE By H L.. T hree important fungal leaf spot diseases, tan spot, Septoria/Stagonospora nodorum blotch (SNB) and Septoria tritici blotch (STB), commonly occur (often as a complex) in North Dakota and have the potential to reduce test weight and yield by 50 percent. Among these, tan spot is the most common leaf spot disease found in all wheat classes throughout North Dakota., Ergot of Rye Claviceps purpurea zErgot is a disease of Rye. The Ergotis the dark purplish sclerotium of the fungus that replaces the grain. Ergot of Rye zErgot was very common pathogen of rye. zAlso infect other grains. zErgot contains about forty alkaloids zSummary of life cycle: Ergot of Rye.

In small grain cereals and grasses, ergot is caused by the fungus Clavi-ceps purpurea, which belongs to a group of fungi known as ascomycetes. Several other species of Claviceps also are causal agents of ergot in cereals. For example, C. sorghi, C. sorghicola, and C. africana are causal agents of sorghum ergot. Sclerotia of C. pur- The following phases represent the life cycle of ergot fungi in general: Phase 1 - Windborne ascospores are transported to the host (this mainly takes place in spring) Phase 2 - The spores attach on the pistil surface of the host

Crop Sciences, University of Illinois at. Spots are the most common diseases of shade and. Cause and Disease Cycle.overview highlights how improving plant disease manage. plant disease cycle Opmental cycle changed to enhance yield, for example by. plant disease life cycle Chakraborty-A4-ca-embargo.pdf.become one of the most important diseases of. Ergot of Rye Claviceps purpurea zErgot is a disease of Rye. The Ergotis the dark purplish sclerotium of the fungus that replaces the grain. Ergot of Rye zErgot was very common pathogen of rye. zAlso infect other grains. zErgot contains about forty alkaloids zSummary of life cycle: Ergot of Rye

T hree important fungal leaf spot diseases, tan spot, Septoria/Stagonospora nodorum blotch (SNB) and Septoria tritici blotch (STB), commonly occur (often as a complex) in North Dakota and have the potential to reduce test weight and yield by 50 percent. Among these, tan spot is the most common leaf spot disease found in all wheat classes throughout North Dakota. Ergot of Rye Claviceps purpurea zErgot is a disease of Rye. The Ergotis the dark purplish sclerotium of the fungus that replaces the grain. Ergot of Rye zErgot was very common pathogen of rye. zAlso infect other grains. zErgot contains about forty alkaloids zSummary of life cycle: Ergot of Rye

Life cycle. An ergot kernel, called a sclerotium, develops when a spore of fungal species of the genus Claviceps infects a floret of flowering grass or cereal. The infection process mimics a pollen grain growing into an ovary during fertilization. Ergot of Rye Claviceps purpurea zErgot is a disease of Rye. The Ergotis the dark purplish sclerotium of the fungus that replaces the grain. Ergot of Rye zErgot was very common pathogen of rye. zAlso infect other grains. zErgot contains about forty alkaloids zSummary of life cycle: Ergot of Rye

Claviceps purpurea is a very serious human pathogen and history shows us how it can create HUGE problems if left unchecked, which makes it important to know when to be most on our guard to wa tch out for this fungus. Having cool, wet springs is not good because it signals the ergots to germinate and it also delays the process of fertilization. Summary of Invasiveness Top of page. C. fusiformis is widespread in Africa and India, where the host crop, pearl millet (Pennisetum glaucum), has been grown for thousands of years.The ergot disease it causes became a major yield constraint in India with the introduction of open-pollinated hybrid lines (Thukar and Rai, 2003).Conidia are spread from plant to plant by wind, rain-splash, and insects.

Fungal and Protozoan Diseases of the Digestive System. The life cycle of C. purpurea begins when an ergot kernel, called a sclerotium, infects the host. The fungi continues to undergo proliferation and destroys the plant ovary. The first stage of ergot infection is a white soft tissue, called Sphacelia segetum, that drops out of the host These ascospores are carried out by insects or wind to the flowers of the rye as described in first stage. In this way life cycle ergot is completed. Ergot is collected from fields of rye when the scelerotia are fully developed and projecting from the spike, or they are removed from the grain by shifting.

DISEASES OF FIELD CROPS AND THEIR MANAGEMENT. Life cycle. An ergot kernel, called a sclerotium, develops when a spore of fungal species of the genus Claviceps infects a floret of flowering grass or cereal. The infection process mimics a pollen grain growing into an ovary during fertilization., DISEASES OF FIELD CROPS AND THEIR MANAGEMENT 11 1. Diseases of Barley Life cycle without barberry in Indian conditions. Rust resistance gene pool in India Leaf rust-Lr Lr1, Lr3, Lr9, Lr10, Lr13, Lr14a, • Ergot or Sugary disease-Claviceps fusiformis or C. microcephala..

What Is The Definition Of Ergot Medical Dictionary Free

Life cycle of ergot pdf

Mosquito Life Cycle Mosquito Control US EPA. Ergot of Rye Claviceps purpurea zErgot is a disease of Rye. The Ergotis the dark purplish sclerotium of the fungus that replaces the grain. Ergot of Rye zErgot was very common pathogen of rye. zAlso infect other grains. zErgot contains about forty alkaloids zSummary of life cycle: Ergot of Rye, described the full life cycle of ergot.9 The first obvious effect of the parasite attacking the grass is the so-called ‘honeydew’ (Figure 2), a sticky yellow sugar solution, which when secreted by the infected plant ovary exudes as drops between the affected glumes (sterile bracts) of the rye. The next stage.

Life Cycle of Plasmodiophora Brassicae (With Diagram) Fungi

Life cycle of ergot pdf

Ergot Biology and Control USDA ARS. An analysis of ergot alkaloids in the Clavicipitaceae (Hypocreales, Ascomycota) and ecological implications Article (PDF Available) in Symbiosis 46(1) · January 2008 with 527 Reads https://simple.wikipedia.org/wiki/Housefly Jul 09, 2017 · Life Cycle of Claviceps • The species of Claviceps are parasitic on grasses. It causes ergot disease. The fungus attacks only the inflorescence of its host. Grains are replaced by blunt trilateral horn-shaped black sclerotia known by the name of ergots. • These sclerotia are resting stages..

Life cycle of ergot pdf


Sep 29, 2014В В· What Is The Definition Of Ergot - Medical Dictionary Free Online Medical Dictionary Online. How To Convert pdf to word without software - Duration: Ergot Poisoning (MU CAFNR) - Duration: In this article we will discuss about the life cycle of plasmodiophora brassicae with the help of suitable diagrams.. Cook and Swartz (1930) showed that the life cycle of P. brassicae comprises two distinct phases, the haplophase (primary phase) and the diplophase (secondary phase).

Ergot is a disease of plants, particularly small grains such as rye and barley and other grasses, which is caused by species of Claviceps, in particular C. purpurea, C. paspalli, and C. fusiformis.These fungi invade the female sex organs of the host plant and replace the ovary with a mass of fungal tissue known as a sclerotium. The sclerotia, also called ergots, are about the same size and A CHEMICAL INVESTIGATION OF ERGOT OF RYE GENERAL A. ORIGIN OF NAME The name for the drug ergot of rye, possibly better known as simply ergot, is derived from the old as to the life cycle of ergot, which is stated briefly as follows: The origin of the ergot sclerotium, developed on. 3-

The life cycle typically takes up two weeks, but depending on conditions, it can range from 4 days to as long as a month. The adult mosquito emerges onto the water's surface and flies away, ready to … Jul 09, 2017 · Life Cycle of Claviceps • The species of Claviceps are parasitic on grasses. It causes ergot disease. The fungus attacks only the inflorescence of its host. Grains are replaced by blunt trilateral horn-shaped black sclerotia known by the name of ergots. • These sclerotia are resting stages.

Ergot: Biology and Control Stephen Alderman Plant Pathologist USDA-ARS National Forage Seed Production Research Center Corvallis, OR 97331 February, 2006 Introduction When we look at the tens of thousands of known species of fungi, few have had a greater impact on society than ergot. Over a thousand compounds have been extracted or Crop Sciences, University of Illinois at. Spots are the most common diseases of shade and. Cause and Disease Cycle.overview highlights how improving plant disease manage. plant disease cycle Opmental cycle changed to enhance yield, for example by. plant disease life cycle Chakraborty-A4-ca-embargo.pdf.become one of the most important diseases of.

T hree important fungal leaf spot diseases, tan spot, Septoria/Stagonospora nodorum blotch (SNB) and Septoria tritici blotch (STB), commonly occur (often as a complex) in North Dakota and have the potential to reduce test weight and yield by 50 percent. Among these, tan spot is the most common leaf spot disease found in all wheat classes throughout North Dakota. Claviceps purpurea is a very serious human pathogen and history shows us how it can create HUGE problems if left unchecked, which makes it important to know when to be most on our guard to wa tch out for this fungus. Having cool, wet springs is not good because it signals the ergots to germinate and it also delays the process of fertilization.

A CHEMICAL INVESTIGATION OF ERGOT OF RYE GENERAL A. ORIGIN OF NAME The name for the drug ergot of rye, possibly better known as simply ergot, is derived from the old as to the life cycle of ergot, which is stated briefly as follows: The origin of the ergot sclerotium, developed on. 3- The entire life cycle of the organism Claviceps is quite complex but for simplicity, this organism and the other fungi mentioned above replace the developing ovaries of the developing seed with hard masses of fungal tissue called sclerotia (sometimes called "Ergots"). The sclerotia are brown to purple-black in color and contain the ergot alkaloids.

Life cycle of ergot pdf

Systematic Mycology and Microbiology Laboratory - Invasive Fungi Fact Sheets Udbatta disease or false ergot of rice - Balansia oryzae-sativae Balansia oryzae-sativae is an ascomycete related to the ergot fungi that is pathogenic on a number of grasses but is of particular concern when it occurs on rice. Infection of the plant is systemic and Fungal and Protozoan Diseases of the Digestive System. The life cycle of C. purpurea begins when an ergot kernel, called a sclerotium, infects the host. The fungi continues to undergo proliferation and destroys the plant ovary. The first stage of ergot infection is a white soft tissue, called Sphacelia segetum, that drops out of the host

ASMscience Rye Ergot and Witches a cooperative learning

Life cycle of ergot pdf

Ergot Sources Cultivation and Uses (With Diagram). The life cycle typically takes up two weeks, but depending on conditions, it can range from 4 days to as long as a month. The adult mosquito emerges onto the water's surface and flies away, ready to …, DISEASES OF FIELD CROPS AND THEIR MANAGEMENT 11 1. Diseases of Barley Life cycle without barberry in Indian conditions. Rust resistance gene pool in India Leaf rust-Lr Lr1, Lr3, Lr9, Lr10, Lr13, Lr14a, • Ergot or Sugary disease-Claviceps fusiformis or C. microcephala..

DISEASES OF FIELD CROPS AND THEIR MANAGEMENT

(PDF) REPRODUCTION OF FUNGI. DISEASES OF FIELD CROPS AND THEIR MANAGEMENT 11 1. Diseases of Barley Life cycle without barberry in Indian conditions. Rust resistance gene pool in India Leaf rust-Lr Lr1, Lr3, Lr9, Lr10, Lr13, Lr14a, • Ergot or Sugary disease-Claviceps fusiformis or C. microcephala., T hree important fungal leaf spot diseases, tan spot, Septoria/Stagonospora nodorum blotch (SNB) and Septoria tritici blotch (STB), commonly occur (often as a complex) in North Dakota and have the potential to reduce test weight and yield by 50 percent. Among these, tan spot is the most common leaf spot disease found in all wheat classes throughout North Dakota..

Aug 17, 2012В В· This review provides a detailed summary of all major ergot epidemics since 1900 in both humans and cattle. Special attention is devoted to the ergotism symptoms and to the regulations surrounding the control of ergot in the food supply. 1 The Diversity of Fungi Chapter 20 Fungi are in Domain Eukarya Key features of fungi Mycelium is the body of a fungus Secrete enzymes to break down foodMade of hyphae Single, elongated cells with multiple nuclei OR

Claviceps purpurea is a very serious human pathogen and history shows us how it can create HUGE problems if left unchecked, which makes it important to know when to be most on our guard to wa tch out for this fungus. Having cool, wet springs is not good because it signals the ergots to germinate and it also delays the process of fertilization. The life cycle of a silkworm, from a microscopic egg to a beautiful moth is simply mind-blowing. Let’s explore the different stages of life of a silkworm. Silk is a …

T hree important fungal leaf spot diseases, tan spot, Septoria/Stagonospora nodorum blotch (SNB) and Septoria tritici blotch (STB), commonly occur (often as a complex) in North Dakota and have the potential to reduce test weight and yield by 50 percent. Among these, tan spot is the most common leaf spot disease found in all wheat classes throughout North Dakota. infection deals with the ergot disease of the domestic grain rye. The well-known life cycle of the fungus typically starts in the spring or early summer from sclerotia (resting structures) that have over-wintered, probably on the ground. The fungus remains dormant until favorable conditions of …

Summary of Invasiveness Top of page. C. fusiformis is widespread in Africa and India, where the host crop, pearl millet (Pennisetum glaucum), has been grown for thousands of years.The ergot disease it causes became a major yield constraint in India with the introduction of open-pollinated hybrid lines (Thukar and Rai, 2003).Conidia are spread from plant to plant by wind, rain-splash, and insects. In some higher fungi such as ergot, sclerotia become detached and remain dormant until favorable growth conditions return. Sclerotia initially were mistaken for individual organisms and described as separate species until Louis René Tulasne proved in 1853 …

Ergot of Rye Claviceps purpurea zErgot is a disease of Rye. The Ergotis the dark purplish sclerotium of the fungus that replaces the grain. Ergot of Rye zErgot was very common pathogen of rye. zAlso infect other grains. zErgot contains about forty alkaloids zSummary of life cycle: Ergot of Rye Life Cycle: Adult cutworms and army worms are moths, and the females lay eggs on leaves and leaf sheaths near the ground. These eggs hatch within a few days and initially the larvae (63, cutworm; 64, armyworm) feed close to where they hatch. The larvae are found in cracks in the soil or under rocks during the day, feeding at night or early in

The following phases represent the life cycle of ergot fungi in general: Phase 1 - Windborne ascospores are transported to the host (this mainly takes place in spring) Phase 2 - The spores attach on the pistil surface of the host The life cycle of C. gigantea is similar to other species of Claviceps. The fungus overwinters as sclerotia on the ground or mixed with seed. In the spring, sclerotia germinate to produce stalked stromata with heads containing many embedded perithecia. Ascospores serve as the primary inoculum; they are

The life cycle of a silkworm, from a microscopic egg to a beautiful moth is simply mind-blowing. Let’s explore the different stages of life of a silkworm. Silk is a … Dec 26, 2011 · You just clipped your first slide! Clipping is a handy way to collect important slides you want to go back to later. Now customize the name of a clipboard to store your clips.

ergot infection by extending the duration of the flowering stage and thus enabling more opportunity for infection to occur. After a plant has become infected the affected seed ovary will begin to enlarge and harden, ultimately forming a mature ergot body (2). The complete life … The life cycle typically takes up two weeks, but depending on conditions, it can range from 4 days to as long as a month. The adult mosquito emerges onto the water's surface and flies away, ready to …

The author strongly suggests that the afflicted girls who testified at the trials were the victims not of witchcraft but rather of ergot poisoning. Students use a reprint of the paper; the play, The Crucible by Arthur Miller; and various scientific references to learn about the … Dec 26, 2011 · You just clipped your first slide! Clipping is a handy way to collect important slides you want to go back to later. Now customize the name of a clipboard to store your clips.

Ergot is a disease of plants, particularly small grains such as rye and barley and other grasses, which is caused by species of Claviceps, in particular C. purpurea, C. paspalli, and C. fusiformis.These fungi invade the female sex organs of the host plant and replace the ovary with a mass of fungal tissue known as a sclerotium. The sclerotia, also called ergots, are about the same size and It is estimated that a third of all fungi reproduce using more than one method of propagation; for example, reproduction may occur in two well-differentiated stages within the life cycle of a

EC1880 Ergot of Small Grain Cereals and Grasses and its

Life cycle of ergot pdf

Life Cycle of a Grasshopper Lesson for Kids Study.com. Ergot toxicity results from ingestion of alkaloid compounds produced by the fungus Claviceps purpurea. This fungus infects cereals and grasses, most commonly rye, wheat, and oats. The seeds of the plants turn dark as they are filled with the fungal sclerotia, and this grossly visible structure is …, A CHEMICAL INVESTIGATION OF ERGOT OF RYE GENERAL A. ORIGIN OF NAME The name for the drug ergot of rye, possibly better known as simply ergot, is derived from the old as to the life cycle of ergot, which is stated briefly as follows: The origin of the ergot sclerotium, developed on. 3-.

Fungal and Protozoan Diseases of the Digestive System. Life Cycle: Adult cutworms and army worms are moths, and the females lay eggs on leaves and leaf sheaths near the ground. These eggs hatch within a few days and initially the larvae (63, cutworm; 64, armyworm) feed close to where they hatch. The larvae are found in cracks in the soil or under rocks during the day, feeding at night or early in, Dec 30, 2011В В· Ergot is an alkaloid containing dried sclerotium of a fungus, containing mainly indole alkaloids called ergolines. It is traditionally used to labour to assist delivery (oxytocic) and to reduce post-partum haemorrhage. The pharmacognosy of ergot of rye is discussed below..

Ergot an overview ScienceDirect Topics

Life cycle of ergot pdf

Guide to Wheat Diseases and Pests. Ergot of Rye Claviceps purpurea zErgot is a disease of Rye. The Ergotis the dark purplish sclerotium of the fungus that replaces the grain. Ergot of Rye zErgot was very common pathogen of rye. zAlso infect other grains. zErgot contains about forty alkaloids zSummary of life cycle: Ergot of Rye https://en.wikipedia.org/wiki/Ergot Sep 25, 2019В В· The life cycle of C. purpurea begins when an ergot kernel, called a sclerotium, infects the host. The fungi continues to undergo proliferation and destroys the plant ovary. The first stage of ergot infection is a white soft tissue, called Sphacelia segetum, that drops out of the host..

Life cycle of ergot pdf

  • Ergot-Reproduction
  • Animal Nutrition Association of Canada

  • infection deals with the ergot disease of the domestic grain rye. The well-known life cycle of the fungus typically starts in the spring or early summer from sclerotia (resting structures) that have over-wintered, probably on the ground. The fungus remains dormant until favorable conditions of … High-yielding strains of Claviceps purpurea (Fr.) Tul, grown on a defined medium, have been used for a study of the biosynthesis of the peptide ergot alkaloid, ergotamine. l-[U-14C]tryptophan, dl-[2-14C]mevalonic acid lactone, sodium [2-14C]acetate, sodium [14C]formate and the methyl group of l-[methyl-14C]methionine were efficiently incorporated into the peptide alkaloids and specifically

    It is estimated that a third of all fungi reproduce using more than one method of propagation; for example, reproduction may occur in two well-differentiated stages within the life cycle of a Asexual life cycle Passively drifting meiospores that settle on food and grow into large aseptate mycelium. Sporangiophores grow into the air, and swell at the tip to form mitosporangia. Sexual life cycle Compatible Rhizopus mycelia ( + and – mating types) meet, and grow special hyphae that meet at the tips. Cross walls form behind the tips and

    Ergot: Biology and Control Stephen Alderman Plant Pathologist USDA-ARS National Forage Seed Production Research Center Corvallis, OR 97331 February, 2006 Introduction When we look at the tens of thousands of known species of fungi, few have had a greater impact on society than ergot. Over a thousand compounds have been extracted or The author strongly suggests that the afflicted girls who testified at the trials were the victims not of witchcraft but rather of ergot poisoning. Students use a reprint of the paper; the play, The Crucible by Arthur Miller; and various scientific references to learn about the …

    Claviceps purpurea is a very serious human pathogen and history shows us how it can create HUGE problems if left unchecked, which makes it important to know when to be most on our guard to wa tch out for this fungus. Having cool, wet springs is not good because it signals the ergots to germinate and it also delays the process of fertilization. Ergot of Rye Claviceps purpurea zErgot is a disease of Rye. The Ergotis the dark purplish sclerotium of the fungus that replaces the grain. Ergot of Rye zErgot was very common pathogen of rye. zAlso infect other grains. zErgot contains about forty alkaloids zSummary of life cycle: Ergot of Rye

    Sep 25, 2019В В· The life cycle of C. purpurea begins when an ergot kernel, called a sclerotium, infects the host. The fungi continues to undergo proliferation and destroys the plant ovary. The first stage of ergot infection is a white soft tissue, called Sphacelia segetum, that drops out of the host. The entire life cycle of the organism Claviceps is quite complex but for simplicity, this organism and the other fungi mentioned above replace the developing ovaries of the developing seed with hard masses of fungal tissue called sclerotia (sometimes called "Ergots"). The sclerotia are brown to purple-black in color and contain the ergot alkaloids.

    A CHEMICAL INVESTIGATION OF ERGOT OF RYE GENERAL A. ORIGIN OF NAME The name for the drug ergot of rye, possibly better known as simply ergot, is derived from the old as to the life cycle of ergot, which is stated briefly as follows: The origin of the ergot sclerotium, developed on. 3- described the full life cycle of ergot.9 The first obvious effect of the parasite attacking the grass is the so-called ‘honeydew’ (Figure 2), a sticky yellow sugar solution, which when secreted by the infected plant ovary exudes as drops between the affected glumes (sterile bracts) of the rye. The next stage

    Asexual life cycle Passively drifting meiospores that settle on food and grow into large aseptate mycelium. Sporangiophores grow into the air, and swell at the tip to form mitosporangia. Sexual life cycle Compatible Rhizopus mycelia ( + and – mating types) meet, and grow special hyphae that meet at the tips. Cross walls form behind the tips and rye is usually mixed with other cool season species such as triticale. Hay: Cereal rye can be cut for hay when it is in the early heading stage of development (Oelke et al., 1990). It provides the best hay forage when it is grown with other species such as red or crimson clover, or annual ryegrass (Oelke et al., 1990).

    Sep 25, 2019В В· The life cycle of C. purpurea begins when an ergot kernel, called a sclerotium, infects the host. The fungi continues to undergo proliferation and destroys the plant ovary. The first stage of ergot infection is a white soft tissue, called Sphacelia segetum, that drops out of the host. Sep 29, 2014В В· What Is The Definition Of Ergot - Medical Dictionary Free Online Medical Dictionary Online. How To Convert pdf to word without software - Duration: Ergot Poisoning (MU CAFNR) - Duration:

    Ergot toxicity results from ingestion of alkaloid compounds produced by the fungus Claviceps purpurea. This fungus infects cereals and grasses, most commonly rye, wheat, and oats. The seeds of the plants turn dark as they are filled with the fungal sclerotia, and this grossly visible structure is … Ergot: Biology and Control Stephen Alderman Plant Pathologist USDA-ARS National Forage Seed Production Research Center Corvallis, OR 97331 February, 2006 Introduction When we look at the tens of thousands of known species of fungi, few have had a greater impact on society than ergot. Over a thousand compounds have been extracted or

    Jul 09, 2017 · Life Cycle of Claviceps • The species of Claviceps are parasitic on grasses. It causes ergot disease. The fungus attacks only the inflorescence of its host. Grains are replaced by blunt trilateral horn-shaped black sclerotia known by the name of ergots. • These sclerotia are resting stages. Sep 25, 2019 · The life cycle of C. purpurea begins when an ergot kernel, called a sclerotium, infects the host. The fungi continues to undergo proliferation and destroys the plant ovary. The first stage of ergot infection is a white soft tissue, called Sphacelia segetum, that drops out of the host.

    The following phases represent the life cycle of ergot fungi in general: Phase 1 - Windborne ascospores are transported to the host (this mainly takes place in spring) Phase 2 - The spores attach on the pistil surface of the host The life cycle of C. gigantea is similar to other species of Claviceps. The fungus overwinters as sclerotia on the ground or mixed with seed. In the spring, sclerotia germinate to produce stalked stromata with heads containing many embedded perithecia. Ascospores serve as the primary inoculum; they are