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Medium 9781576337356

Organic Chemistry: CLEP Chemistry

Ace Academics Ace Academics ePub
Medium 9789351380528

Solid-Ch-10

Ajay Kumar Saxena Laxmi Publications PDF

10

Magnetic Properties

10.1 ORIGIN OF MAGNETIC PROPERTIES OF MATERIALS

We know that a small circular current-carrying loop has a magnetic moment associated with it. So motion of electrons in atoms is responsible for magnetism and quantised nature of electronic motion gives rise to the fundamental unit of magnetic dipole moment, the Bohr magneton mB.

For a circular loop of area A and carrying a current I, the dipole moment is IA. For an electron of charge e and mass m rotating in a circular orbit of radius r at an angular velocity w, the magnetic dipole moment is w

1 m = IA = - e p r2 = - ewr2

(10.1)

2p

2

F I

H K

The angular momentum

Æ

| J | = m | r × v | = mwr2

(10.2)

therefore,

Æ

m =−

FH e IK J

2m

(10.3)

The angular momentum is quantised in units of h/(2p) where h is Planck’s constant. Therefore, the

Æ

lowest non-zero value for | m | is mB = eh/4p m = 9.2741 ¥ 10–24 J T –1 (SI units) or 9.2741 ¥ 10–21 erg Oe–1 (CGS units).

No electron can have a magnetic moment below mB.

Thus, orbiting/spinning of electrons on the whole may impart a permanent magnetic moment to atoms.

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Medium 9780253352736

5 The Proterozoic Eon

Dale A. Russell Indiana University Press ePub

Fig 5.1. The Hoggar Mountains, near the hermitage of Charles de Foucault in southern Algeria, are representative of late Archean and early Proterozoic continental landscapes that hosted only microbial life. The local environment is too dry to support complex Phanerozoic-like ecosystems, such as the rain forests to the south in the Congo basin. Photograph courtesy of Harold Heatwole.

Spanning nearly two billion years, the Proterozoic is the longest division of geologic time. All of later time is less than the average span of its three subdivisions, the Paleo-, Meso- and Neoproterozoic (Amthor et al. 2003; Knoll 2003). The eon may be characterized as an age of microbial evolution. Most organisms, as individuals, remained microscopic during all but the last 3 percent of the eon. It has been necessary to rely on radiometric dates to calibrate its physical history, rather than fossils as is typical of post-Proterozoic divisions of geologic time. Severe glaciations and stepped increases in the oxygen content of the atmosphere occurred near the beginning and end of the eon. As presently understood, various interpretations of the physical and biological history of the Proterozoic are not entirely consistent with each other. The narrative presented here represents an approximation that in the future will be rendered more precise with the rapid accumulation of knowledge.

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Medium 9781780643083

1: Position

Crafer, K CABI PDF

1 

Position

1.1  The Evolution of the Garden Centre

Plants have been an essential component of life throughout human history,

­initially as a food source, but increasingly for their ornamental and aesthetic values. The development of home ownership and single household occupancy dwellings helped create the ornamental horticulture market that is seen today.

While plant nurseries are a long established concept, the use of the term

‘garden centre’ is far more recent and ill defined. Stewarts garden centres in

Dorset are amongst a number of businesses who claim to be the first in the UK, having seen the concept of growing hardy plants in containers for sale in Toronto,

Canada, in the mid-1950s (Stewarts Garden Centres, 2014). An embryonic industry using similar techniques was developing in the USA at this time. Regardless of the precise date, the sector has developed rapidly and has changed in all recognition from the earliest examples.

What have been these drivers for change?

1.1.1  Development of technologies for container plant production

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Medium 9781780644554

10: Business Continuity

Wapling, A. CABI PDF

10 

Business Continuity

J. Hebdon

Emergency Preparedness, Resilience and Response Senior Officer,

NHS England Central Team, UK

Key Questions 

Why is business continuity so important for all organizations?

What is the PDCA cycle?

How do you develop a business continuity system?

How do you assess the impact of an incident on your organization?

10.1  Introduction

Business continuity is important for all organizations, from single-handed general practitioner practices to multisite trusts. It is not only important to protect an organization’s reputation and the safety of staff, patients and customers, but it also gives the organization an underpinning understanding of its functions and processes and their importance. This understanding will enable easier creation of emergency plans, especially those that rely on the collapse of other functions to protect or provide a new service. It should not be underestimated how much business continuity planning will help other preparedness areas; for example, business continuity workforce planning gives a framework to support pandemic influenza planning, winter resilience plans and planning for industrial action. It is also important not to forget that the functions in the emergency plans will need to be protected by contingency arrangements of their own; for example, how decontamination will occur without a decontamination facility.

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Medium 9780253006028

3 Tracemaker Habitats and Substrates

Anthony J. Martin Indiana University Press PDF

3

T R ACEM A K ER H A BI TATS

A N D SU B ST R AT ES

CH A NGE I N A F EW EASY ST EPS

I nearly stepped on the snake, mistaking it for a stick on the trail leading into maritime forest. My oversight was understandable, as the trail was cluttered with branches, leaves, and pine needles, and the snake was relatively small, only about 50 cm (20 in) long. It was also stiff and torpid from the cool shade cast by the long shadows of late afternoon, helping it to blend in with other nearby twigs. Sensing a learning opportunity that could not be ignored, I reached down to pick it up, and it responded by writhing slowly and gently along my forearm. Nonetheless, a few students behind me screamed when they realized what I held. I was amused that my Moses impression had provoked such a response, and I waited a few seconds until their anxiety lessened before talking about snakes, their tracemaking, their habitats, and the substrates of those habitats.

The trail was well known to me because of many field trips led along it, and that day was another one. I was accompanied on this trip by a large group of students and my friend and colleague, Steve Henderson from

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Medium 9780253012821

14 Sunspots

John Sallis Indiana University Press ePub

 

Boston

September

They come and go with the clouds, fading into the surrounding shadows as the clouds come to block the direct sunlight, disappearing entirely whenever the clouds are sufficiently dense, then reappearing as if by magic. If they appear on the forest floor, then some of the growth that is sparsely spread across that expanse is also illuminated, its shiny leaves sparkling in the same light that casts the sunspots. If the clearing comes right after a severe thunderstorm, then the growth and the grassy areas adjacent to the forest glisten all the more radiantly, almost as the surface of the sea, in direct sunlight, sparkles so brightly that it itself becomes virtually invisible. For light not only illuminates things but also conceals them, shelters them with a glistening veil; the more intense the sunlight becomes, the more impenetrably the veil is spread before them, and the more insistently they refuse to yield to our vision. Yet they hide, not as in a darkness that would enshroud them, but rather in brightness so abundant that it glazes them with invisibility.

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Medium 9781780641478

4: Loop-mediated isothermal amplification (LAMP)

Boonham, N.; Tomlinson, J.; Mumford, R. CABI PDF

4

Loop-mediated isothermal amplification (LAMP)

Jenny Tomlinson*

Fera, Sand Hutton, York, UK

4.1  Introduction

Detection methods based on the polymerase chain reaction (PCR) are well established and allow sensitive and specific detection of pests and pathogens, typically within a few hours. However, PCR requires accurate thermal cycling, and the instrumentation required for this is relatively complex and expensive, and so its use is to a large extent limited in laboratory facilities. PCR amplification products are conventionally detected using methods such as gel electrophoresis. This approach is inexpensive and flexible, but is relatively time-consuming and not ideally suited to high-throughput applications. Amplification by PCR can be monitored in real time by using fluorescence; while this reduces the time required and enables a higher throughput, relatively sophisticated equipment is required to perform concurrent thermal cycling and fluorescence measurement. Amplification methods that work under isothermal conditions have been developed as alternatives to PCR. Because these methods do not require thermal cycling, they can be carried out using simpler equipment and, as a result, they are potentially more accessible for use in locations where complex and/or costly instrumentation is not available.

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Medium 9781576753705

5: More Powerful Than a Locomotive

Seidensticker, Bob Berrett-Koehler Publishers ePub

IN THE NEXT THREE CHAPTERS we will look carefully at nine “HighTech Myths,” each of which should sound familiar—perhaps even seductive. Each will be illustrated with claims from respected sources. Once we have this common understanding, the claims and the associated myths will be refuted.

In this chapter we look at the two most general myths that are “more powerful than a locomotive”: that technology change is exponential and that technology is inevitable. But like Superman, who was also supposed to be more powerful than a locomotive, these are fiction. Raising these myths out of unconscious acceptance and exposing their flaws should help you to recognize and reject them in the future.

In the three short decades between now and the turn of the millennium,
millions of ordinary, psychologically normal people
will face an abrupt collision with the future.

—ALVIN TOFFLER, Future Shock (1970)

The explosive and even startling change that Moore’s Law has accurately predicted for forty years directly applies only to the narrow field of semiconductors. However, many observers have seen this constantly increasing progress in other aspects of daily life. For example, economist Kenneth Boulding said in 1970, “The world of today … is as different from the world in which I was born as that world was from Julius Caesar’s. I was born [in 1910] in the middle of human history… . Almost as much has happened since I was born as happened before.” According to this observation, the carousel on which we are riding is spinning faster and faster. 64

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Medium 9780253006820

10. Intra-Urban Variations in Vulnerability Associated with Extreme Heat Events in Relationship to a Changing Climate

Sara C Pryor Indiana University Press ePub

D. P. JOHNSON, V. LULLA, AND A. C. STANFORTH

In the developing literature on the nature of climate change and its potential impact on society, vulnerability is an emerging pervasive theme. As can be seen in chapter 1 of this volume, vulnerability, by its very nature, is a multidisciplinary and multidimensional concept and thus requires multiple levels of definition and examination (Bankoff 2001, Bankoff 2003). Vulnerability is also a term that has been recently utilized as a “catch-all” phrase and thus is in danger of losing some of its descriptive effectiveness (Cutter et al. 2008). Vulnerability is so encompassing because it stems from multiple conditions that could represent the social, health, intelligence, or economic status of an individual or location (Wisner 2004). For the present discussion, we are concerned with the vulnerability of populations to a changing climate; our definitions will focus on health and social vulnerability to extreme events, such as those that will likely punctuate climate change globally, particularly heat waves. This chapter intends to introduce vulnerability in the context of extreme heat and to present a case study where such an analysis of vulnerability has taken place.

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Medium 9781780643137

1: The History of Animal Trade

Phillips, C.J.C. CABI PDF

The History of Animal Trade

1

1.1  Introduction

Our ancestors existed as hunter gatherers, and before that as anthropoid apes. The hunter gatherers had varied diets, which gave them security as a population against climatic extremes that favoured certain plant and animal types (Milton, 2000). The costs and risks of procuring meat and animal products were high and many were primarily gatherers. However, meat, once it was obtained, was a concentrated source of energy and protein, the most important nutrients that they required for survival. Not only did hunter gatherers in different parts of the world have quite varied diets, depending on availability, they were also free to migrate to utilize different fauna and flora sources, depending on the season and weather patterns.

Settled agriculture, adopted over a period of just a few thousand years beginning about 10,000 years ago, offered the opportunity for higher yields from plants and animals that were farmed in small areas. However, the static nature of this activity and the enhanced resource requirements of this form of food production, in the form of a regular water supply and a nutrient-rich soil, increased exposure to climatic and seasonal extremes. The inevitable variation in productivity could only be absorbed into a successful existence if humans cooperated with neighbouring groups, so that food surpluses in one region were transported to others where the need was greater. Thus our cognitive skills in organizing this trade, coupled with our highly social behaviour, combined to make plant and animal raising a viable alternative to hunter gathering when societies cooperated by trading in surplus goods.

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Medium 9781845939625

6. Making the Surface of Fleshy Fruit: Biosynthesis, Assembly and Role of the Cuticular Layer

P Nath;  M Bouzayen; A K Mattoo CAB International PDF

6

Making the Surface of Fleshy Fruit:

Biosynthesis, Assembly and Role of the

Cuticular Layer

Justin Lashbrooke,1,2,3 Fabrizio Costa2 and Asaph Aharoni1*

1Department of Plant Sciences, Weizmann Institute of Science,

Rehovot, Israel; 2Research and Innovation Centre, Fondazione Edmund

Mach, TN, Italy; 3Institute for Wine Biotechnology, Stellenbosch

University, Stellenbosch, South Africa

6.1 Introduction to the Plant Cuticle

The primary barrier between the atmosphere and the aerial parts of higher plants is the cuticular membrane or the cuticle.

The constituents of this hydrophobic extracellular membrane, typically comprised of soluble waxes and polymerized lipids, are produced and secreted by the plant’s epidermal cells (Kunst and

Samuels, 2003; Pollard et al., 2008).

Lipids consisting mostly of C16 to C20 fatty acids are polymerized to form a matrix known as cutin (Schreiber, 2010).

The cutin matrix is both embedded with waxes (intracuticular) and covered with a thin layer of surface (epicuticular) waxes

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Medium 9781576336366

Moles: GED Chemistry

Ace Academics Ace Academics ePub
Medium 9780253356024

3. Vascular Plants and Vertebrate Wildlife

Jr John O Whitaker Indiana University Press ePub

Because of the great diversity of natural communities and vegetation types found within the borders of Indiana, there is a corresponding diversity of vascular plant species. Floras published in 1881, 1900, and 1940 recorded native species in the state totaling 1,194, 1,400, and 1,838, respectively (Deam 1940). Charles C. Deam, Indiana’s preeminent botanist of the twentieth century, was exceptionally thorough in his efforts to document the state’s flora. He believed that the number of native species for Indiana would never surpass 1,900, yet the total now approaches 2,000 (K. Yatskievych, unpublished data). This has been the result of intensive and extensive fieldwork, so that the current list of all vascular plants in Indiana (Table P-1) now totals more than 2,900 species, subspecies, and varieties.

This total includes many introduced, alien, and adventive species that now reside in Indiana and are either reproducing or have sustaining populations in the state. Many, if not most, of these species introductions have occurred since Deam’s exhaustive survey (Deam 1940). Perhaps another factor contributing to the increase in species number is the natural range expansions of certain species that entered the state in the late twentieth century, particularly those with wind-dispersed seeds. These additions, offset by the probable extirpations of species before they were documented, make it safe to say that the number of native vascular plant species known to occur in Indiana in the past two centuries has been approximated at 2,000. Of this number, 55 species are thought to be extirpated from Indiana (Indiana Natural Heritage Data Center 2005).

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Medium 9781786390325

18 Role of Plant Growth-Promoting Rhizobacteria (PGPR) in Degradation of Xenobiotic Compounds and Allelochemicals

Singh, H.B.; Sarma, B.K.; Keswani, C. CABI PDF

18 

Role of Plant Growth-Promoting

Rhizobacteria (PGPR) in Degradation of

Xenobiotic Compounds and Allelochemicals

Deepika Goyal,1 Janmejay Pandey1* and Om Prakash2#

Department of Biotechnology, School of Life Sciences, Central University of Rajasthan,

Bandarsindri, NH-8, Kishangarh, Ajmer-305817, Rajasthan, India; 2Microbial Culture

Collection, National Centre for Cell Sciences, Pune-411007, Maharashtra, India

1

they are characterized by extreme chemical and thermodynamic stability. While this property makes them ideally suited for industrial application and enhances their commercial value, it also makes them extremely

18.1.1  Xenobiotic compounds as priority persistent in the environment. Furthermore, environmental pollutants many of the xenobiotic compounds, e.g. hexachlorocyclohexane (HCH), pentachloropheContamination of Earth’s environment with nol (PCP), polychlorinated biphenols (PCB), toxic xenobiotic pollutants has been a major etc., also exhibit a strong tendency to biocause of concern for several decades. This accumulation. Therefore, organisms posisituation has emerged largely due to non-­ tioned at higher levels in food chains and judicious production, usage and disposal of food webs (including human beings) will xenobiotic pollutants during urbanization tend to have greater accumulation of these and activities related to industrialization toxic compounds compared to those organand agriculture. Xenobiotic compounds are isms present at the lower levels. Noticeably, man-made chemicals (such as explosives, these bioaccumulating xenobiotic compounds pesticides, fungicides, synthesized azo dyes, can be passed from mothers to their children industrial solvents, alkanes, polycyclic aro- during embryonic development as well as matic hydrocarbons, dioxins and furans, through post-­natal breastfeeding. Apart from polychlorinated biphenyls, chlorinated the tendency to bioaccumulate, a large numaromatic compounds and nitro-aromatic ber of xenobiotic compounds can also impart compounds, petroleum products, and bromi- toxic effects to human beings, ranging from nated flame retardants, etc.) that are synthe- acute toxicity, mutagenicity, carcinogenicity, sized for industrial and agricultural application. teratogenicity, etc. In addition, they are harmA majority of the xenobiotic compounds ful due to their ability to poison animals and do not have any known natural source and plants and alter ecosystem functions.

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