bluuebunny/crossref_metadata_2025 huggingface dataset:
Watershed Hydrology and Chemistry in the Alaskan Boreal Forest: The Central Role of Permafrost
Authors: Hinzman Larry D. , Petrone Kevin C.
Published: November 2020

Hydrological processes exert strong control over biological and climatic processes in every ecosystem. They are particularly important in the boreal zone, where the average annual temperatures of the air and soil are relatively near the phase-change temperature of water (Chapter 4). Boreal hydrology is strongly controlled by processes related to freezing and thawing, particularly the presence or absence of permafrost. Flow in watersheds underlain by extensive permafrost is limited to the near-surface active layer and to small springs that connect the surface with the subpermafrost groundwater. Ice-rich permafrost, near the soil surface, impedes infiltration, resulting in soils that vary in moisture content from wet to saturated. Interior Alaska has a continental climate with relatively low precipitation (Chapter 4). Soils are typically aeolian or alluvial (Chapter 3). Consequently, in the absence of permafrost, infiltration is relatively high, yielding dry surface soils. In this way, discontinuous permafrost distribution magnifies the differences in soil moisture that might normally occur along topographic gradients. Hydrological processes in the boreal forest are unique due to highly organic soils with a porous organic mat on the surface, short thaw season, and warm summer and cold winter temperatures. The surface organic layer tends to be much thicker on north-facing slopes and in valley bottoms than on south-facing slopes and ridges, reflecting primarily the distribution of permafrost. Soils are cooler and wetter above permafrost, which retards decomposition, resulting in organic matter accumulation (Chapter 15). The markedly different material properties of the soil layers also influence hydrology. The highly porous near-surface soils allow rapid infiltration and, on hillsides, downslope drainage. The organic layer also has a relatively low thermal conductivity, resulting in slow thaw below thick organic layers. The thick organic layer limits the depth of thaw each summer to about 50–100 cm above permafrost (i.e., the active layer). As the active layer thaws, the hydraulic properties change. For example, the moisture-holding capacity increases, and additional subsurface layers become available for lateral flow. The mosaic of Alaskan vegetation depends not only on disturbance history (Chapter 7) but also on hydrology (Chapter 6).
Interfacial Phenomena with Carbon Dioxide Soluble Surfactants
Authors: Johnston Keith P. , Lee C. T.
Published: November 2020

A fundamental understanding of colloid and interface science for surfactant design in CO2-based systems is emerging on the basis of studies of interfacial tension and surfactant adsorption (da Rocha et al., 1999) along with complementary studies of colloid structure (Chillura-Martino et al., 1996; Meredith and Johnston, 1999; Wignall, 1999) and stability (Meredith and Johnston, 1999; O’Neill, 1997; Yates et al., 1997). The interfacial tension, γ, between a supercritical fluid (SCF) phase and a hydrophilic or lipophilic liquid or solid, along with surfactant adsorption, play a key role in a variety of processes including nucleation, coalescense and growth of dispersed phases, formation of microemulsions and emulsions (Johnston et al., 1999), particle and fiber formation, atomization, foaming (Goel and Beckman, 1995), wetting, adhesion, lubrication, and the morphology of blends and composites (Watkins et al., 1999). The first generation of research involving surfactants in SCFs addressed water/oil (w/o) microemulsions (Fulton and Smith, 1988; Johnston et al., 1989) and polymer latexes (Everett and Stageman, 1978) in ethane and propane (Bartscherer et al., 1995; Fulton, 1999; McFann and Johnston, 1999). This work provided a foundation for studies in CO2, which has modestly weaker van der Waals forces (polarizability per volume) than ethane. Consequently, polymers with low cohesive energy densities and thus low surface tensions are the most soluble in CO2: for example, fluoroacrylates (DeSimone et al., 1992), fluorocarbons, fluoroethers (Singley et al., 1997), siloxanes, and to a lesser extent propylene oxide. Since CO2 is nonpolar (unlike water) and has weak van der Waals forces (unlike lipophilic phases), it may be considered to be a third type of condensed phase. Surfactants with the above types of “CO2-philic” segments and a “CO2-phobic” segment have been used to form microemulsions (Harrison et al., 1994; Johnston et al., 1996), emulsions (da Rocha et al., 1999; Jacobson et al., 1999a; Lee et al., 1999b), and organic polymer latexes (DeSimone et al., 1994) in CO2. Microemulsion droplets are typically 2–10 nm in diameter, making them optically transparent and thermodynamically stable, whereas kinetically stable emulsion droplets and latexes in the range of 200 nm to 10 mm are opaque and thermodynamically unstable.
The Enterococcus faecalis Information Gate
Authors: Wakabayashi Kenichi , Yamamura Masayuki
Published: November 2020

Information exchange between cellular compartments allows us to engineer systems based around cooperative principles. In this chapter we consider a unique bacterial communication system, the conjugative plasmid transfer of Enterococcus faecalis. Using these bacteria, we describe how to engineer a logically controlled information gate and build a logical inverter based upon it. Cellular computing is an alternative computing paradigm based on living cells. Microscale organisms, especially bacteria, are well suited for computing for several reasons. A small culture provides an almost limitless supply of bacterial “hardware.” Bacteria can be stored and easily modified by gene recombination. In addition, and important for our purposes, bacteria can produce various signal molecules that are useful for computation. DNA-binding proteins recognize specific regulatory regions of DNA, bind them, and regulate their genetic expression. These proteins are available for use as computing signals inside the cell. Weiss et al. have shown, for example, how to construct logic circuits based on gene expression regulated by DNA-binding proteins. Some signal molecules are associated with intercellular communications between individuals. Intercellular communication is one of the fundamental characteristics of multicellular organisms, but it is also found in single-celled microorganisms, including bacteria. Communication mediated by homoserine lactones can widely be seen in various Gram-negative bacteria. The mechanism of this behavior was well characterized in Vibrio fischeri, due to their bioluminescent activity mediated by homoserine lactones. It has been shown that bacterial information transfer can be engineered as an extension of Escherichia coli into which the lux genes of Vibrio fischeri are transformed. The communication abilities of bacteria therefore allow us to build microbial information processors for cellular computing. Communication mechanisms in Gram-positive bacteria are not yet well understood. One of the exceptions to this is the conjugative plasmid transfer system in Enterococcus faecalis. E. faecalis conjugate in response to a pheromone is released by other cells. Pheromones are seven- or eight-residue amino peptides produced in E. faecalis. In the case of cPD1, the pheromone is produced by truncation of a 22-residue precursor that is the signal peptide of a lipoprotein.
Historical Perspectives in Hemostasis, Coagulation, and Fibrinolysis: A Foundation for Understanding Thrombotic Disorders and Developing Effective Treatment
Authors: Becker Richard C. , Spencer Frederick A.
Published: November 2020

Hemostasis, the prompt cessation of bleeding at a site of vascular injury, is among the most fundamental physiologic and teleologically vital defense mechanisms in nature. Without a functionally intact hemostatic mechanism, death could ensue rapidly even after minor traumas associated with everyday life. In mammalian blood coagulation, regulated by a complex network of integrated biochemical events, five protease factors (f ) (fIIa [thrombin], fVIIa, fIXa, fXa, and protein C) interact with five cofactors (tissue factor, f VIIIa, fVa, thrombomodulin, and protein S) to regulate the generation of fibrin (Davidson et al., 2003). Although each component of the mammalian coagulation network has unique functional properties, available data based on gene organizations, protein structure, and sequence analysis suggest that it may have resulted from the reduplication and diversification of two gene structures over 400 million years ago. A vitamin K–dependent serine protease is composed of a γ-carboxylated glutamic acid (GLA) epidermal growth factor-like (EGF) 1–EGF 2-serine protease domain structure common to fVII, fIX, fX, and protein C, and the A1-A2-B-AB-C1-C2 domain structure common to fV and fVIII. Prothrombin is also a vitamin K–dependent serine protease; however, it contains kringle domains rather than EGF domains (suggesting a replacement during gene duplication and shuffling). Analyses of active site function amino acid residues reveal distinguishing characteristics of thrombin from other serine proteases, supporting its position as the ancestral blood enzyme (Krem and Cera, 2002; McLysaght et al., 2002). The rapid transformation of fluid blood to a gel-like substance (clot) has been a topic of great interest to scientists, physicians, and philosophers since the days of Plato and Aristotle ( Jewett, 1892; Lee, 1952). However, it was not until the beginning of the 18th century that blood clotting (coagulation) was appreciated as a means to stem blood loss from wounds (hemostasis) (Petit, 1731). As with other areas of science, the microscope played a pivotal role in the understanding of coagulation. In the mid-17th century, Marcello Malpighi separated the individual components of a blood clot into fibers, cells, and serum (Forester, 1956).
Venous Thromboembolism
Authors: Becker Richard C. , Spencer Frederick A.
Published: November 2020

Blood clotting within the venous circulatory system, in contrast to arterial thrombosis, occurs at a relatively slow pace in response to stagnation of flow (stasis) and activation of coagulation. As with arterial thrombosis, vascular injury, either direct in the setting of trauma or indirect as a diffuse, systemic inflammatory response (that ultimately causes endothelial cell damage), represents an important stimulus. Venous thrombi are intravascular deposits composed predominantly of erythrocytes and fibrin, with a variable contribution of platelets and leukocytes. In a majority of cases, thrombosis begins in areas of slow flow within the venous sinuses of valve cusp pockets either in the deep veins of the calf or upper thigh or at sites of direct injury following trauma (Kakkar et al., 1969; Nicolaides et al., 1971). Stasis predisposes to thrombosis most profoundly in the setting of inflammatory states and activated coagulation factors. Slowed blood flow impairs the clearance of coagulation proteases, which through bioamplification increases the local concentration of thrombin substrate. If local thromboresistance is impaired, as may be the case with inherited or acquired thrombophilias (see Chapter 24), thrombosis occurs. Blood flow velocity is reduced by indwelling catheters, which also causes focal endothelial injury, peripheral edema, pregnancy, and valve cusp damage from prior venous thrombosis and/or chronic venous insufficiency (Trottier et al., 1995). Although venous thrombosis can occur in a variety of sites, the most common encountered in clinical practice is within the deep veins of the lower extremity. Thrombi developing within the veins of the calf or thigh can serve as a nidus for growth (propagation), which may cause complete venous obstruction, or embolize to the lungs (pulmonary embolism).
Novel Platelet Antagonists
Authors: Becker Richard C. , Spencer Frederick A.
Published: November 2020

The development of pharmacologic agents that inhibit platelet performance could not have proceeded without a fundamental knowledge of normal biology and a clear understanding of the laws that govern cellular events in the circulatory system. The adhesion of platelets to a site of vessel wall injury is mediated by von Willebrand factor (vWF), which binds to the platelet glycoprotein (GP) Ib/IX-V complex receptor (and the GPIIb/IIIa receptor under high shear stress conditions). Monoclonal antibodies to vWF have been developed and tested in animal models, as has aurintricarboxylic acid (Strony et al., 1990), a triphenylmethyl compound that inhibits vWF binding. To date, investigation in humans has not taken place, perhaps because of concerns regarding the potential risk for hemorrhagic complications. Nevertheless, the scientific community remains interested in vWF and its platelet surface receptor as potential pharmacology-directed targets. Although the GPIIb/IIIa receptor antagonists are best known for their ability to inhibit platelet aggregation, under high shear stress conditions vWF can also bind the GPIIb/IIIa receptor, facilitating adhesion. As a result, GPIIb/IIIa antagonists may have an impact on both platelet adhesion and aggregation. As previously discussed, platelet activation is followed by a series of intracellular events that culminate in the release of calcium and substances that augment platelet aggregation and support coagulation protease binding. Thus, pharmacologic agents that inhibit initial surface receptor–mediated activation may also impair platelet aggregation. Several natural prostanoids (prostaglandin [PG] E1 and PGI2) can inhibit platelet activation and aggregation by elevating cyclic adenosine monophosphate (cAMP) levels. Although the mechanism is complex, the primary mode of inhibition is through the activation of adenylate cyclase (with a subsequent rise in cAMP concentrations), which in turn prevents calcium mobilization. The clinical application of PGE1 and PGI2 has been limited by their effect on vascular tone, producing substantial systemic hypotension (Emmons et al., 1967; Terres et al., 1989), and by extensive first-pass metabolism in the lungs (70% of the active compound is rapidly cleared) (Kleiman et al., 1994).
Combination Pharmacotherapy
Authors: Becker Richard C. , Spencer Frederick A.
Published: November 2020

The goal of improving coronary arterial patency, microcirculatory blood flow, and myocardial perfusion represents the essence of fibrinolytic–adjunctive therapy combinations. Because fibrinolytic resistance, patency without perfusion, and reocclusion are platelet-mediated phenomena, considerable emphasis has been placed on the development of platelet antagonists. Coronary arterial thrombi consist of platelets and fibrin bound in a tightly packed meshwork. Platelets modify the intrinsic properties of the fibrin network, causing changes in permeability and vasoelasticity, which decrease fibrinolysis rates. The addition of aspirin and the glycoprotein (GP) IIb/IIIa receptor antagonist abciximab modulates the interaction of platelets and fibrin, improving both accessibility to fibrinolytics and the overall rates of fibrinolysis (Collet et al., 2001). The Thrombolysis in Myocardial Infarction (TIMI) 14 trial (Antman et al., 1999) randomized 888 patients with ST-segment elevation myocardial infarction (MI) to receive (1) accelerated tissue plasminogen activator (tPA; ≤100 mg) plus standard dose of unfractionated heparin (UFH); (2) tPA (920 mg bolus) plus abciximab (0.25 mg/kg bolus, 7 μg/min); (3) streptokinase (800,000 to 1.5 million units) and low-dose UFH; or (4) abciximab plus low-dose UFH. TIMI 3 flow rates 90 minutes from treatment initiation were 52%, 53%, 42%, and 32%, respectively. In subsequent dose/strategy studies, a combination of tPA (35 mg) plus abciximab and tPA (15 mg bolus, 31 mg over 60 minutes) plus abciximab revealed 63% and 73% TIMI 3 flow rates, respectively. Rates of major hemorrhage were similar in all tPA treatment groups. The Strategies for Patency Enhancement in the Emergency Department (SPEED) trial (SPEED Group, 2000) included two phases. Phase A (n = 241) randomized patients to receive either abciximab (bolus plus infusion) alone or combined with 5 U, 7.5 U, 10 U, 5 U + 2.5 U, or 5U + 5 U of reteplase. Phase B tested the best strategy from phase A (abciximab plus 5 U + 5 U of reteplase) against 10 U + 10 U of reteplase. In phase A, 62% of the abciximab–reteplase 5 U + 5 U patient group had TIMI 3 flow rates at 60 to 90 minutes vs. 27% of those given abciximab alone (p = .001).
Thrombin-Directed Therapy
Authors: Becker Richard C. , Spencer Frederick A.
Published: November 2020

Anticoagulant therapy in general is designed to prevent either the generation or activity of thrombin; however, a cell-based model of coagulation provides a physiologic view of individual phases of the process, allowing more specific targets for attenuating the initiation, priming, or propagation of thrombus formation. Future categorization schemes will consider individual coagulation factors, individual sites on a given coagulation factor, and specific phases of coagulation to better identify an agent’s biochemical and physiologic activity. Unfractionated heparin (UFH) is a heterogeneous, negatively charged mucopolysaccharide consisting of approximately 18 to 50 saccharide units (molecular weight 5000–30,000 Da). Antithrombin (AT), required for the interaction (and subsequent neutralization) of UFH with thrombin and coagulation proteases including factors Xa, IXa, XIa, and XIIa, is bound by one third of administered drug (only molecules containing the critical pentasaccharide sequence can bind AT). Following IV administration, UFH binds to a variety of plasma proteins, endothelial cells, and macrophages, explaining, in part, the wide variability in anticoagulant effects for a given dose. It is cleared from the circulation through both a rapid saturable mechanism and a slower first-order mechanism. As a result, there is a dose-dependent half-life ranging from 60 minutes after a dose of 100 U/kg to 180 minutes for a dose of 400 U/kg (Beguin et al., 1988; Lam et al., 1976). Heparin-induced thrombocytopenia and hemorrhage are the most feared complications of UFH administration (see Chapter 29). Other adverse effects include osteopenia (with long-term administration). Low-molecular-weight heparin (LMWH) is prepared by the depolymerization of porcine UFH. A variety of processes are used, giving distinctive products whose molecular weights range from 4,000 to 6,500 Da (Hirsh and Levine, 1992). Like UFH, approximately one third of LMWH polysaccharide chains contain the pentasaccharide binding site for antithrombin. The LMWH–antithrombin complex (consisting of a predominance of shorter chain polysaccharides) has relatively weak antithrombin activity but retains the ability to inactivate factor Xa. The ratio of anti-Xa activity to anti-IIa (antithrombin) activity varies from 2:1 to 4:1. Similar to UFH, LMWH is not able to inhibit thrombin bound to fibrin (Weitz, 1997).
Novel Anticoagulants
Authors: Becker Richard C. , Spencer Frederick A.
Published: November 2020

While all anticoagulants have, to a certain extent, novel properties, the development of agents that inhibit specific coagulation proteases through structural affinity and can be inhibited themselves by the concomitant production of antidotes (drug–antidote pair construct) has the potential to revolutionize the field. With the evolution of our thinking toward hemostasis and thrombosis has come new pharmacologic constructs for safe and effective treatment. Aptamers are single-stranded nucleic acids that inhibit a protein’s function by folding into a specific three-dimensional structure that defines high-affinity binding to the target protein (White et al., 2000). The term aptamer (from the Latin aptus, “to fit”) was coined by Ellington and Szostak (1990) following their pioneering work published originally in Nature. Based on iterative selection techniques, aptamers that bind essentially any protein or small molecule can be generated. A high-affinity, specific inhibitor that interacts with functional groups (on both the nucleic acid and the protein) can be constructed if a small amount of pure target is available. The initiation point for aptamer development is a combinatorial library composed of single-stranded nucleic acids (RNA, DNA, or modified RNA), typically containing 20 to 40 randomized positions (1024 different sequences). Isolation of high-affinity nucleic acid ligands involves a process known as SELEX (systemic evolution of ligands by exponential enrichment). The starting library is incubated with the protein of interest. Nucleic acid molecules that adopt conformations that allow target protein binding are subsequently partitioned from other sequences (that do not bind the protein). The bound sequences are removed and amplified by reverse transcription and polymerase chain reaction (PCR) (for RNA-based libraries) or PCR alone (for DNA-based libraries). After repeating the process several times, the selected ligands are secured and evaluated for binding affinity and ability to inhibit activity (of the target protein). Postselection optimization steps typically include (1) reduction in aptamer length (from a starting molecule of 80–100 nucleotides to 40 nucleotides); (2) enhanced stability in biologic systems (achieved by substitution of ribonucleotides with 2-amino, 2´-fluoro, or 2´-0-alkyl nucleotides and protection from exonuclease digestion by 3´ end capping); and (3) reduced renal clearance (achieved by increasing the molecules’ mo lecular weight through site-specific addition of polyethylene glycol moieties or other hydrophobic groups.
Venous Thromboembolism Prophylaxis
Authors: Becker Richard C. , Spencer Frederick A.
Published: November 2020

Venous thromboembolism represents a true worldwide medical problem that is encountered within all realms of practice. Venous thromboembolism (VTE) occurs in approximately 100 patients per 100,000 population yearly in the United States and increases exponentially with each decade of life (White, 2003). Approximately one-third of patients with symptomatic deep vein thrombosis (DVT) experience a pulmonary embolism (PE). Death occurs within 1 month in 6% of patients with DVT and 12% of those with PE. Early mortality is associated strongly with presentation as PE, advanced age, malignancy, and underlying cardiovascular disease. An experience dating back several decades has provided a better understanding of disease states and conditions associated with VTE (Anderson and Spencer, 2003). Given the potential morbidity and mortality associated with VTE, it is apparent that prophylaxis represents an important goal in clinical practice. A variety of anticoagulants including unfractionated heparin, low-molecular-weight heparin (LMWH), and warfarin have been studied. More recently, two new agents have been developed that warrant discussion. Fondaparinux underwent a worldwide development program in orthopedic surgery for the prophylaxis of VTE. The program consisted mainly of four large, randomized, double-blind phase II studies comparing fondaparinux (SC), at a dose of 2.5 mg starting 6 hours postoperatively, with the two enoxaparin regimens approved for VTE prophylaxis—40 mg qd or 30 mg twice daily beginning 12 hours postoperatively. The results support a greater protective effect with fondaparinux, yielding a 55.2% relative risk reduction of VTE (Bauer et al., 2001; Eriksson et al., 2001; Lassen et al., 2002; Turpie et al., 2001, 2002; ). A European program of three large-scale clinical trials (MElagatran for THRombin inhibition in Orthopedic surgery [METHRO] I, II, and III, and EXpanded PRophylaxis Evaluation Surgery Study [EXPRESS]) (Eriksson et al., 2002a, b, 2003a, b) evaluated the safety and efficacy of subcutaneous melagatran followed by oral ximelagatran compared with LMWH for thromboprophylaxis following total hip replacement (THR) and total knee replacement (TKR) surgery.
Platelet Antagonists
Authors: Becker Richard C. , Spencer Frederick A.
Published: November 2020

Platelet antagonists play an important role in both primary and secondary prevention of atherothrombotic events. Despite their proven benefit, individual response (and protection) varies considerably, emphasizing the importance of developing monitoring tools (tested prospectively in clinical trials) that can better determine the degree of platelet inhibition that is both safe and effective. Platelet function studies were developed originally for the evaluation of patients with unexplained bleeding and have contributed greatly to the understanding, diagnosis, and management of hereditary abnormalities such as von Willebrand disease and Glanzmann’s thrombasthenia (platelet glycoprotein [GP] IIb/IIIa receptor deficiency). Although conventional platelet function studies (turbidimetric aggregometry) have technical limitations that preclude their routine use for gauging antithrombotic therapy, they may provide guidance when hemorrhagic complications arise and in determining pretreatment risk in individuals suspected of having an intrinsic platelet abnormality. The bleeding time, considered an indicator of primary hemostasis (platelet plug formation), is defined as the time between making a small standardized skin incision and the precise moment when bleeding stops. The test is performed with a template, through which the medial surface of the forearm is incised under 40 mmHg standard pressure. A normal bleeding time is between 6 and 10 minutes. Although considered a “standardized” test of platelet function, the bleeding time can be influenced by a variety of factors, including platelet count, qualitative abnormalities, and features intrinsic to the blood vessel wall (George and Shattil, 1991). Platelet adhesion is the initiating step in primary hemostasis. Although platelet binding is an important component of this process, there are many others, including blood flow rate, endothelial cell function, adhesive proteins, and the subendothelial matrix. The original test used for assessing adhesion, platelet retention, was based on adherence to glass bead columns. The current laboratory evaluation of platelet function is based predominantly on turbidimetric platelet aggregometry (also known as light transmission aggregometry). This test is performed by preparing platelet-rich plasma (with platelet-poor plasma as a control) and eliciting an aggregation response with adenosine diphosphate, epinephrine, collagen, arachidonic acid, and ristocetin (Born, 1962).
Development of Prosocial Behavior
Authors: Hamburg David A. , Hamburg Beatrix A.
Published: November 2020

The next several chapters follow a developmental sequence of examining opportunities for learning peaceful human relationships in programs appropriate for children at different stages of growth and development. The focus on prosocial behavior is broadly applicable to the basic orientation of this book. The primary focus of this chapter is on the role of prosocial behavior in the earliest years of life. Nancy Eisenberg and Paul Mussen of the University of California at Berkeley provide a major analytical examination of what is known about prosocial behavior—its development and the underlying mechanisms at work. This body of research examines how children are socialized to behave prosocially—what are the personal attributes and capabilities involved, and what are the impacts of the social environment that inhibit or facilitate expressions of generosity, helping, and comforting? There are fundamental questions on this topic; much has been learned, but many questions await future research to clarify significant issues. Why are some individuals predisposed toward prosocial conduct, whereas others are not? How does genetic makeup predispose one to behave compassionately? What are the specific interactions of children of differing ages, gender, and past experiences with major socialization agents such as parents, teachers, schools, siblings, peers, cultural and religious institutions, and the mass media? What are the cultural values that foster or reduce prosocial behavior? The other major variability has to do with differences within an individual’s responses to the current context—the fact that everyone’s behavior varies from time to time, according to the situation. The research evidence confirms the malleability of behavior across all ages and indicates ample opportunity for the learning of prosocial behavior and its modifiability over the course of development. So, ways can be found for teachers, parents, and others to contribute toward shaping individual prosocial behavior and thereby, in the aggregate, to promote and sustain a more constructive society. Eisenberg and Mussen distinguish between prosocial behavior and altruism:… • Prosocial behavior is defined as voluntary action that is intended to help another individual or a group. Although voluntary in nature, prosocial actions may be performed for a variety of reasons—for reward, approval, sense of duty, or because of genuine sympathy. • Altruism is one particular type of prosocial behavior stemming from intrinsic motivation (i.e., concern, sympathy, values, self-rewards), not from personal gain. In practice, these two forms of behavior are often considered together as prosocial.
Education for Peace: Concepts and Institutions
Authors: Hamburg David A. , Hamburg Beatrix A.
Published: November 2020

What is distinctive about education for peace? It subsumes much else that precedes it in this book, drawing especially on the basic concepts and educational processes for conflict resolution. But it goes beyond education for conflict resolution in that it addresses the crossing of adversarial large-scale intergroup boundaries. This includes hostility across national boundaries and hostility across ethnic, religious, or political boundaries within a nation. The first condition is conducive to international war; the second condition is conducive to civil war. The large-scale hostilities have not been so much the focus of attention in recent education as interpersonal and community education for conflict resolution. Education for peace is more complex and daunting than education for conflict resolution. But the stakes are so high, and likely to get so exceedingly dangerous in the twenty-first century, that education for peace must be addressed in serious and sustained ways—the sooner the better. In this and the next two chapters, we try to clarify the following:… 1. The essential content of education for peace, or at least the critical issues that need to be addressed 2. How to upgrade such information and concepts on a continuing, longterm basis so that education for peace can grow in strength over the decades ahead 3. How to make such content personally meaningful and widely available throughout the world… What evocative and thoughtful efforts have addressed the preceding three points? Peace education works toward giving children, adolescents, and young adults clear ideas about how to contribute to the creation of peaceful communities on both local and global scales. Starting from a low baseline, this century has seen an increased interest in peace education, but still it has not entered mainstream education. Although many schools have adopted conflict-resolution programs, they usually stop short of addressing the larger issues of war and peace. Yet there is a connection between the two. The challenge is to move beyond a narrow arena (for example, the school) to a broader view—indeed a worldwide outlook. The worldwide predilection to violence is both a serious constraint and profound challenge to peace education. So, too, is the paucity of research in this field.
Estimation by Associations and Trends
Authors: Wei James
Published: November 2020

Product engineers are often challenged to estimate: 1. the properties of new or obscure classes of material that have not been extensively studied before, or have never been made before; 2. the property changes on a material due to physical and chemical modifications; 3. the properties under a variety of ambient conditions, such as temperatures, pressures, electromagnetic fields, and prolonged environmental exposures and weathering. When theoretical understanding is insufficient and quantitative correlations are not available, we can often make useful qualitative estimations by using fragmentary empirical structure–property relations. The principal tools are observations of associations and trends, which are often the only methods available in biological, health, safety, and environmental properties. Association is based on analogy, or the probabilistic assumption that “similar substances have similar properties.” Does x◦, the material in question, resemble a known substance x1 or a class of substances {x1, x2, . . ., xi , . . .} that have known properties and structure? If we can find such a match, then we can use it to make qualitative property estimates for x◦.We know that metals are nearly always solids at room temperature, but mercury is an exception. Trend is based on the study of the variation of properties among the substances {x1, x2, . . ., xi, . . .} and how they depend on structure variations, which amounts to qualitative and empirical structure–property relations. For example, we know that a larger molecule tends to have higher melting and boiling points, but chlorobenzene has lower melting point than benzene. Thomas Midgley used qualitative trend analysis to help him to discover the chlorofluorocarbons as refrigerants. He did not have a well-organized database, nor did he have an established method of analysis and prediction, and his method was ad hoc and empirical. What he did know was that sulfur dioxide and ammonia were in use as refrigerants. He looked at the periodic table of nonmetallic elements and observed the trend that small compounds of these elements tend to become less flammable when we move from the left to the right of the table, which is certainly true in the sequence CH4, NH3, H2O, and HF.
Research Frontiers
Authors: Wei James
Published: November 2020

There are many challenging intellectual opportunities for the research community to create new knowledge in molecular structure–property relations, and to enlarge the toolbox of product engineering, that promise to inspire and accelerate new product innovations. There is a suspicion that there are inexhaustible families of material structures waiting to be discovered and to be used. Periodically, this suspicion is confirmed by the announcement of yet another family of interesting materials. In the 1970s, the synthetic zeolites were heralded as a new class of compounds with a microstructure of pores with molecular sizes. These became very useful in making adsorbents and catalysts. This discovery also led to the invention of many other families of microporous materials. Then came the broader concept of self-assembly of material, namely of organic and inorganic compounds that organize themselves into intricate patterns, now counted within the umbrella of nanotechnology. Two of the recent Nobel Prizes in chemistry offer proof that this field of new synthesis is full of possibilities and honor. We once thought that carbon existed only in the graphite, diamond, and amorphous forms. Now we know that not only can it exist in the buckminsterfullerene form of C60, but also in many other related forms that are spherical and cylindrical tubules. The notion of an electrically conducting polymer was not seriously considered until the invention of the electrically conducting polyacetylenes by Heeger, McDiarmid, and Shirakawa. The synthesis of new material can also be divided into the twin paths of incremental synthesis of the derivatives of known structures and the wildcat synthesis of totally unrelated structures. The incremental approach is used when a material with interesting properties is discovered, and research chemists will swarm around it to make every conceivable derivative to see whether they can enlarge the menu to choose from, and to ensure that the new province is well explored. The opposite wildcat approach seeks new and exciting families of material that would not be found by adhering exclusively to known provinces. The discovery of interesting natural materials not recognized before is a continuing theme of romance.
Informal Networks : The Company behind the Chart
Authors: Krackhardt David , Hanson Jeffrey R.
Published: November 2020

Many executives invest considerable resources in restructuring their companies, drawing and redrawing organizational charts only to be disappointed by the results. That’s because much of the real work of companies happens despite the formal organization. Often what needs attention is the informal organization, the networks of relationships that employees form across functions and divisions to accomplish tasks fast. These informal networks can cut through formal reporting procedures to jump start stalled initiatives and meet extraordinary deadlines. But informal networks can just as easily sabotage companies’ best laid plans by blocking communication and fomenting opposition to change unless managers know how to identify and direct them. Learning how to map these social links can help managers harness the real power in their companies and revamp their formal organizations to let the informal ones thrive. If the formal organization is the skeleton of a company, the informal is the central nervous system driving the collective thought processes, actions, and reactions of its business units. Designed to facilitate standard modes of production, the formal organization is set up to handle easily anticipated problems. But when unexpected problems arise, the informal organization kicks in. Its complex webs of social ties form every time colleagues communicate and solidify over time into surprisingly stable networks. Highly adaptive, informal networks move diagonally and elliptically, skipping entire functions to get work done. Managers often pride themselves on understanding how these networks operate. They will readily tell you who confers on technical matters and who discusses office politics over lunch. What’s startling is how often they are wrong. Although they may be able to diagram accurately the social links of the five or six people closest to them, their assumptions about employees outside their immediate circle are usually off the mark. Even the most psychologically shrewd managers lack critical information about how employees spend their days and how they feel about their peers. Managers simply can’t be everywhere at once, nor can they read people’s minds. So they’re left to draw conclusions based on superficial observations, without the tools to test their perceptions.
Making Invisible Work Visible : Using Social Network Analysis to Support Strategic Collaboration
Authors: Cross Rob , Borgatti, Stephen P.
Published: November 2020

Over the past decade, significant restructuring efforts have resulted in organizations with fewer hierarchical levels and more permeable internal and external boundaries. A byproduct of these restructuring efforts is that coordination and work increasingly occur through informal networks of relationships rather than through channels tightly prescribed by formal reporting structures or detailed work processes. For example, informal networks cutting across core work processes or holding together new product development initiatives are not found on formal organizational charts. Rather, these networks often promote organizational flexibility, innovation, and efficiency, as well as quality of products or services, by virtue of effectively pooling unique expertise. Supporting collaboration and work in these informal networks is increasingly important for organizations competing on knowledge and an ability to innovate and adapt. Unfortunately, critical informal networks often compete with and are fragmented by such aspects of organizations as formal structure, work processes, geographic dispersion, human resource practices, leadership style, and culture. This is particularly problematic in knowledge-intensive settings where management is counting on collaboration among employees with different types of expertise. People rely very heavily on their network of relationships to find information and solve problems—one of the most consistent findings in the social science literature is that who you know often has a great deal to do with what you come to know. Yet both practical experience and scholarly research indicate significant difficulty in getting people with different expertise, backgrounds, and problemsolving styles to effectively integrate their unique perspectives. Simply moving boxes on an organizational chart is not sufficient to ensure effective collaboration among high-end knowledge workers. Movement toward de-layered, flexible organizations and emphasis on supporting collaboration in knowledge-intensive work has made it increasingly important for executives and managers to attend to informal networks within their organizations. Performance implications of effective informal networks can be significant as the rapidly growing social capital tradition has indicated at the individual, team, and organizational levels. Yet while research indicates ways managers can influence informal networks at both the individual and whole network levels, executives seem to do relatively little to assess and support critical, but often invisible, informal networks in organizations.
Unifying Laws in Multidisciplinary Power-Law Phenomena: Fixed-Point Universality and Nonextensive Entropy
Authors: Robledo Alberto
Published: November 2020

Critical, power-law behavior in space and/or time manifests in a large variety of complex systems [12] within physics and, nowadays, more conspicuously in other fields, such as biology, ecology, geophysics, and economics. Universality, the same power law holding for completely different systems, is a consequence of the characteristic self-similar, scale-invariant property of criticality, and can be understood in terms of basins of attraction of the renormalization-group (RG) fixed points. However, the guiding quality of a variatkmal approach has been seemingly lacking in the theoretical studies of critical phenomena. Here we give an account of entropy extrema associated with fixed points of RG transformations. As illustrations, we consider simple one-dimensional models of random walks and nonlinear dynamical systems. In describing these systems we consider distribution and/or time relaxation functions with power-law decay that may have infinite first- or second- and higher-order moments. When these moments diverge, we observe the emergence of nonexponential or non-Gaussian fractal properties that can be measured by the nonextensive Tsallis entropy index q. We note that the presence of nonextensive properties may signal situations of hindered movement among the system's possible configurations. Some representative applications within physics, but with suggested or recognized connections to other fields, are critical behavior in fluids and magnets, anomalous diffusion processes, transitions to chaos in nonlinear systems, and relaxation properties of supercooled liquids near the glass formation. Two prototypical model systems serve to illustrate the development of critical states characterized by power laws from generic states described by exponential behavior. These are random walks and nonlinear iterated maps that we discuss below in some detail. Random walks [18] are suitable, for example, for representing Brownian motion (molecular thermal motion under the microscope), but also for many types of data originating from diverse disciplines. One type is that which comes in the form of a "time series," a temporal sequence of measured values, for instance, stock market prices in economics or electroencephalographic potentials in medicine.
Nonextensive Effects in Hamiltonian Systems
Authors: Rapisarda Andrea , Latora Vito
Published: November 2020

The Boltzmann-Gibbs formulation of equilibrium statistical mechanics depends crucially on the nature of the Hamiltonian of the JV-body system under study, but this fact is clearly stated only in the introductions of textbooks and, in general, it is very soon neglected. In particular, the very same basic postulate of equilibrium statistical mechanics, the famous Boltzmann principle S = k log W of the microcanonical ensemble, assumes that dynamics can be automatically an easily taken into account, although this is not always justified, as Einstein himself realized [20]. On the other hand, the Boltzmann-Gibbs canonical ensemble is valid only for sufficiently short-range interactions and does not necessarily apply, for example, to gravitational or unscreened Colombian fields for which the usually assumed entropy extensivity postulate is not valid [5]. In 1988, Constantino Tsallis proposed a generalized thermostatistics formalism based on a nonextensive entropic form [24]. Since then, this new theory has been encountering an increasing number of successful applications in different fields (for some recent examples see Abe and Suzuki [1], Baldovin and Robledo [4], Beck et al. [8], Kaniadakis et al. [12], Latora et al. [16], and Tsallis et al. [25]) and seems to be the best candidate for a generalized thermodynamic formalism which should be valid when nonextensivity, long-range correlations, and fractal structures in phase space cannot be neglected: in other words, when the dynamics play a nontrivial role [11] and fluctuations are quite large and non-Gaussian [6, 7, 8, 24, 26]. In this contribution we consider a nonextensive JV-body classical Hamiltonian system, with infinite range interaction, the so-called Hamiltonian mean field (HMF) model, which has been intensively studied in the last several years [3, 13, 14, 15, 17, 18, 19]. The out-of-equilibrium dynamics of the model exhibits a series of anomalies like negative specific heat, metastable states, vanishing Lyapunov exponents, and non-Gaussian velocity distributions. After a brief overview of these anomalies, we show how they can be interpreted in terms of nonextensive thermodynamics according to the present understanding.