Design Patterns: Elements of Reusable Object-Oriented Software is a software engineering book describing software design patterns. The book was written by Erich Gamma, Richard Helm, Ralph Johnson, John Vlissides, with a foreword by Grady Booch; the book is divided into two parts, with the first two chapters exploring the capabilities and pitfalls of object-oriented programming, the remaining chapters describing 23 classic software design patterns. The book includes examples in Smalltalk, it has been influential to the field of software engineering and is regarded as an important source for object-oriented design theory and practice. More than 500,000 copies have been sold in 13 other languages; the authors are referred to as the Gang of Four. The book started at a birds of a feather session at OOPSLA'90, "Towards an Architecture Handbook", run by Bruce Anderson, where Erich Gamma and Richard Helm met and discovered their common interest, they were joined by Ralph Johnson and John Vlissides. The original publication date of the book was October 21, 1994 with a 1995 copyright, hence it is cited with a 1995-year, despite being published in 1994.
The book was first made available to the public at the OOPSLA meeting held in Portland, Oregon, in October 1994. In 2005 the ACM SIGPLAN awarded that year's Programming Languages Achievement Award to the authors, in recognition of the impact of their work "on programming practice and programming language design"; as of March 2012, the book was in its 40th printing. Chapter 1 is a discussion of object-oriented design techniques, based on the authors' experience, which they believe would lead to good object-oriented software design, including: "Program to an'interface', not an'implementation'." Composition over inheritance: "Favor'object composition' over'class inheritance'." The authors claim the following as advantages of interfaces over implementation: clients remain unaware of the specific types of objects they use, as long as the object adheres to the interface clients remain unaware of the classes that implement these objects. The authors refer to inheritance as white-box reuse, with white-box referring to visibility, because the internals of parent classes are visible to subclasses.
In contrast, the authors refer to object composition as black-box reuse because no internal details of composed objects need be visible in the code using them. The authors discuss the tension between inheritance and encapsulation at length and state that in their experience, designers overuse inheritance; the danger is stated as follows: "Because inheritance exposes a subclass to details of its parent's implementation, it's said that'inheritance breaks encapsulation'". They warn that the implementation of a subclass can become so bound up with the implementation of its parent class that any change in the parent's implementation will force the subclass to change. Furthermore, they claim that a way to avoid this is to inherit only from abstract classes—but they point out that there is minimal code reuse. Using inheritance is recommended when adding to the functionality of existing components, reusing most of the old code and adding small amounts of new code. To the authors,'delegation' is an extreme form of object composition that can always be used to replace inheritance.
Delegation involves two objects: a'sender' passes itself to a'delegate' to let the delegate refer to the sender. Thus the link between two parts of a system are established only at runtime, not at compile-time; the Callback article has more information about delegation. The authors discuss so-called parameterized types, which are known as generics or templates; these allow any type to be defined without specifying all the other types it uses—the unspecified types are supplied as'parameters' at the point of use. The authors admit that delegation and parameterization are powerful but add a warning: "Dynamic parameterized software is harder to understand and build than more static software." The authors further distinguish between'Aggregation', where one object'has' or'is part of' another object and acquaintance, where one object merely'knows of' another object. Sometimes acquaintance is called'association' or the'using' relationship. Acquaintance objects may request operations of each other, but they aren't responsible for each other.
Acquaintance is a weaker relationship than aggregation and suggests much looser coupling between objects, which can be desirable for maximum maintainability in a design. The authors employ the term ` toolkit' where others might today use ` class library', as in Java. In their parlance, toolkits are the object-oriented equivalent of subroutine libraries, whereas a'framework' is a set of cooperating classes that make up a reusable design for a specific class of software, they state that applications are hard to design, toolkits are harder, frameworks are the hardest to design. Chapter 2 is a step-by-step case study on "the design of a'What-You-See-Is-What-You-Get' document editor called Lexi." The chapter goes through seven problems that must be addressed in order to properly design Lexi, including any constraints that must be follow
The honesty or integrity of individuals can be tested via pre-employment screening from employers. Employers may administer personnel selection tests within the scope of background checks that are used to assess the likelihood that behavior. Integrity tests are administered to assess whether the honesty of the potential candidate is acceptable in respect to theft and counterproductive work behavior; these tests may weigh in on the final personnel decisions. Integrity testing for employment selection became popular during the 1980s. Human Resources personnel found. Polygraph tests were no longer able to be used for screening of most future employees in the United States due to the Employee Polygraph Protection Act of 1988; the two types of tests related to integrity testing are called personality-based measures. The overt test asks about past behavior and attitudes about counterproductive behavior; the personality-based measures of personality traits that are associated with theft and counterproductive behavior.
Integrity tests in the past used self-report pencil formats. Modern tests include at least 1 measurement of psychophysiological parameter like voice analysis, to ensure higher reliability. Integrity tests are designed to assess honesty, trustworthiness, conscientiousness, reliability. Integrity tests were created to foresee counterproductive work behavior while on the job and employee theft. An overt integrity test is a self-report paper and pencil test that asks a subject directly about their honesty, criminal history, attitudes towards drug use, thefts by other people, general questions that show integrity, it is designed to find "undesirable" traits in a person's behavior, past crimes, dishonesty, in order to sort out potential candidates. Overt tests are split into two sections; the first being a series of questions evaluating the subject's attitude towards theft, their beliefs on the frequency of theft, punishment of theft and the assessment of the subject's own honesty. The attitude section assess their own trustworthiness in the workforce.
Typical questions might ask if people believe that everyone can be dishonest or the question might as how honest the test taker is. The second section asks the subject what type and amount of theft and/or counter-productive behavior they have been a part of with past employers or any other illegal behaviors. Typical questions for this section might ask if someone has thought about stealing something or what amount the test taker has stolen from past employers. Examples of overt integrity test are: London House Personnel Selection, the Reid Report, the Stanton Survey, the Phase II Profile; the Reid Report evaluates social behavior, substance use, work background, persistence, valuing of interpersonal relationships, self-restraint, willingness to help others with tasks. The Stanton Survey helps identify if a person will steal merchandise, misuse sick days, break company policy, give unauthorized discounts, counterproductive behaviors. Personality-oriented tests include items that assess personality characteristics that have been shown to relate to counterproductive work behavior.
The test items assess dependability, social conformity, thrill seeking, conscientiousness. Conscientiousness seems to be the biggest personality predictor from the Big Five personality traits that help to predict personality with relation to employment. An example of typical questions might ask if you are more adventurous. Examples of personality-oriented integrity test are the Personnel reaction blank, employment inventory from personnel decisions Inc. and the Hogan personality inventory. The personnel reaction blank is based on California psychological inventory, it tests for sociability, conscientiousness, interval values, self-restraint, acceptance of convention. Employment inventory from personnel decisions Inc. was designed to measure employee deviance. Measure for trouble with authority, thrill seeking, hostility and socialization; the Hogan personality inventory evaluates hostility towards authority, thrill seeking, conscientiousness, confused vocational identity, social insensitivity.
Integrity tests aim to identify prospective employees who are to engage in theft or counterproductive work behavior. Identifying unsuitable candidates can save the employer from problems that might otherwise arise during their term of employment. Integrity tests make certain assumptions, specifically: that persons who have "low integrity" report more dishonest behavior that persons who have "low integrity" try to find reasons in order to justify such behavior that persons who have "low integrity" think others more to commit crimes — like theft, for example; that persons who have "low integrity" exhibit impulsive behavior that persons who have "low integrity" tend to think that society should punish deviant behavior The claim of such tests to be able to detect "fake" answers plays a crucial role in detecting people who have low integrity. Naive respondents believe this pretense and behave accordingly, reporting some of their past deviance and their thoughts about the deviance of others, fearing that if t
Absalón Vásquez Villanueva is an agricultural engineer, university professor and Peruvian politician. He has served as Vice-Minister of Natural Resources and Rural Development and as Vice-Minister of Agriculture. Additionally, he was Minister of Agriculture from 1992 to 1996, the longest term in Peru’s history, during the government of Alberto Fujimori, he was elected as a Congressman of the Republic. In 2014 he ran for the Governorship of the Department of Cajamarca under the Cajamarca Siempre Verde movement, coming in third place with 12.6% of the votes. He was born in Jesús District, Cajamarca Province, Cajamarca Department, he studied agricultural engineering in the National Agrarian University, where he completed a master’s degree in Water and Land Resources Engineering. In 2012 he finished a doctorate in Water Resources with the highest grade in the entire university.. He took up the role of Vice-Minister of Natural Resources and Rural Development in 1988, a post from which he resigned in 1989.
In 1991 he was named Vice-Minister of Agriculture and assumed the role of Minister of Agriculture between the years 1992 and 1996, becoming the longest-serving person to hold this position, with a total of 4 years. From 1996 to 1999 he served as a presidential advisor in agricultural topics. In 2000 he was elected to Congress with more than 700,000 votes. Absalón Vásquez has been accused of various crimes of corruption rooted in his involvement with the Fujimorist government of the 1990s. In 2008, he was sentenced to seven years in prison when he was found responsible for massive forgery of signatures for the Vamos Vecinos party, a group that supported the reelection of Alberto Fujimori, for which he would receive a habeas corpus. After a short time he was acquitted by the Supreme Court with a favorable opinion from the Supreme Attorney. In 2013, he was absolved in a courtroom presided by judge Villa Stein for the case of the “Vladipoles”, in which he was accused of misusing funds for the purchase of propaganda materials supporting Fujimori’s reelection Vásquez began his political career in 1988, when he was named a Vice-Minister in the first government of Alan García, a role from which he resigned in 1989.
He was again elected Vice-Minister in the first government of Alberto Fujimori and fulfilled this role from 1991 to 1992. At that time, he was elected Minister of Agriculture and occupied this position until 1996. After 1996, he served as a presidential advisor in agricultural issues until 2000. In 2000, he was elected to Congress, he ran in 2010 for the role of regional governor of Cajamarca under the Cajamarca Siempre Verde movement. In 2014, he again ran for regional governor of Cajamarca under the Cajamarca Siempre Verde movement, this time achieving third place with more than 12% of valid votes. In 2018, he ran for the third time for regional governor of Cajamarca with the Podemos Perú party, taking fourth place with 11% of votes, he established a system of tariff surcharge for food imports coming from countries that subsidize their producers, with the goal of protecting national producers from unfair competition. He corrected the collectivism of in the property held by Peruvian sugar-producing companies, through Legislative Decree 802 called the Sugar Cooperative Economic & Financial Restructuring Law.
He was an integral part of the team that created the National Program of Soil and Water Conservation called PRONAMACHS. This was a project supporting rural development in the high Andes zones of Perú. 2011, First in Class, Doctorate Degree in Water Resource Engineering 1997, Honorary Doctorate at the Universidad de San Martín de Porres 1977, First in Class, Master’s Degree in Water and Land Resource Engineering Cosecha de Agua de Lluvia en Laderas Semiáridas de la Sierra y su Impacto en el Proceso de Desertificación y Cambio Climático. UNALM “La Molina”. 2012. Cuantificación de la Erosión Hídrica en la Sierra Peruana. UNALM “La Molina”. 2012 Principios Básicos del Riego. UNALM “La Molina”. 2012. Manejo de Cuencas Altoandinas Tomo I y II. UNALM “La Molina”. II Edición. 2000. Manejo de Cuencas Hidrográficas Altoandinas. UNALM “La Molina”. I Edición. 1998. Desarrollo Agrario: Antecedentes y Propuesta de Política para el Siglo XXI. UNALM “La Molina”. 1999. Industria Azucarera Peruana. Balance y Perspectivas. UNALM “La Molina”.
1997. Política Agraria para un Desarrollo Sostenido del Agro Peruano. MINAG. 1994. Modelo de Programación de Riegos en el Cultivo de la Caña de Azúcar en el Perú. ICIA – Trujillo. 1978. Investigación de Operaciones y aplicación de la Ingeniería de Sistemas en el aprovechamiento de los Recursos Hídricos. ICIA – Trujillo. 1979. Modelo de Pronóstico de Riegos en el cultivo de la Caña de Azúcar, ICIA- Trujillo. 1979. Manual del Riego del Cultivo de la Caña de Azúcar en el Perú, ICIA – Trujillo. 1980. Manual de Conservación de Suelos. Convenio Perú – AID, MINAG-AID. 1983. Manual de Rehabilitación de Andenes Incaicos UNALM “La Molina”. 1984. Evolución del Impacto Socio Económico de la Conservación de Suelos y Aguas en la Sierra Peruana, MINAG – AID. 1985. Publicación de Varios trabajos de Investigación en el ISSCT. 1976 – 1981
Adoram Keisi is a retired Israeli professional football player. Keisi played most of his career as a left back in Maccabi Haifa F. C. in which he won 4 championship, one state cup and 2 Toto cups. Keisi is known as a winner who scores crucial goals when needed, he joined his current club Maccabi Haifa from Hapoel Petah Tikva in 1995. After suffering a serious leg injury he recovered to become one of the best left backs in Israel, he has 51 caps and 4 goals for the national team and appeared for Maccabi Haifa in the UEFA Champions League group stage. Keisi is an excellent header who comes forward and has scored many goals while assisting many from the wing. In 2004, financial differences with the club's management led him to leave for his former club. However, in 2005 he returned to Haifa where he has won three league championships and a State Cup title. In 2007, he retired. After Levi left the club, Keisi was appointed as squad director and assistant to the manager Elisha Levi. Haberman, Itzhak. אדורם קייסי.
Maccabi Haifa. Archived from the original on August 18, 2007
Constructivist teaching is based on constructivist learning theory. Constructivist teaching is based on the belief that learning occurs as learners are involved in a process of meaning and knowledge construction as opposed to passively receiving information. Constructivist approach teaching methods are based on constructivist learning theory. John Dewey and Jean Piaget researched childhood education. Dewey's idea of influential education suggests that education must engage with and enlarge exploration of thinking and reflection associated with the role of educators. Contrary to this, Piaget argued that we learn by expanding our knowledge by experiences which are generated through play from infancy to adulthood which are necessary for learning. Both theories are now encompassed by the broader movement of progressive education. Constructivist learning theory states that all knowledge is constructed from a base of prior knowledge; as such, children are not to be treated as a blank slate, make sense of classroom material in the context of his or her current knowledge.
In the constructivist classroom, students work in groups to engage with daily activities. Constructivist teaching methods emphasize communication and social skills, as well as intellectual collaboration; this is different from a traditional classroom where students work alone, learning through repetition and lecture. Activities encouraged in constructivist classrooms include: Experimentation: Students individually perform an experiment and come together as a class to discuss the results. Research can present their findings to the class. Field trips: This allows students to put the concepts and ideas discussed in class in a real-world context. Field trips would be followed by class discussions. Films: These provide visual context and thus bring another sense into the learning experience. Class discussions: This technique is used in all of the methods described above, it is one of the most important distinctions of constructivist teaching methods. Campus wikis: These provide learners with a platform for curating helpful learning resources.
Constructivist approaches can be used in online learning. Tools such as discussion forums and blogs can enable learners to construct knowledge; because existing knowledge schemata are explicitly acknowledged as a starting point for new learning, constructivist approaches tend to validate individual and cultural differences and diversity. Traditional testing is only one facet of constructivist assessment of student success. Assessment consists of personal, thorough interpretation of students' performance in the context of what their out-of-school life. Non-traditional constructivist assessment strategies include: Oral discussions; the teacher allows an open discussion on the topic. KWL Chart; this technique can be used throughout the course of study for a particular topic, but is a good assessment technique as it shows the teacher the progress of the student throughout the course of study. Mind Mapping. In this activity, students categorize the concepts and ideas relating to a topic. Hands-on activities.
These encourage students to manipulate a particular learning tool. Teachers can use a observation to assess student success with the particular material. Pre-testing; this allows a teacher to determine what knowledge students bring to a new topic and thus will be helpful in directing the course of study. Critics have voiced the following arguments against constructivist based teaching instruction: A group of cognitive scientists has questioned the central claims of constructivism, saying that they are either misleading or contradict known findings. One possible deterrent for this teaching method is that, due to the emphasis on group work, the ideas of the more active students may dominate the group's conclusions. While proponents of constructivism argue that constructivist students perform better than their peers when tested on higher-order reasoning, the critics of constructivism argue that this teaching technique forces students to "reinvent the wheel". Supporters counter that "Students do not reinvent the wheel but, attempt to understand how it turns, how it functions."
Proponents argue that students—especially elementary school-aged children—are curious about the world, giving them the tools to explore it in a guided manner will serve to give them a stronger understanding of it. Mayer developed a literature review spanning fifty years and concluded "The research in this brief review shows that the formula constructivism = hands-on activity is a formula for educational disaster." His argument is that active learning is suggested by those subscribing to this philosophy. In developing this instruction these educators produce materials that require learning to be behaviorally active and not be "cognitively active"; that is, although they are engaged in activity, they may not be learning. Mayer recommends using guided discovery, a mix of direct instruction and hands-on activity, rather than pure discovery: "In many ways, guided discovery appears to offer the best method for promoting constructivist learning."Kirchner et al. agree with the basic premise of constructivism, that learners construct knowledge, but are concerned with the instructional design recommendations of this theoretical framework.
"The constructivist description of learning is accurate, but the instructional consequences suggested by constructivists do not follow." (Kirschner, Swel
Microfold cells are found in the gut-associated lymphoid tissue of the Peyer's patches in the small intestine, in the mucosa-associated lymphoid tissue of other parts of the gastrointestinal tract. These cells are known to initiate mucosal immunity responses on the apical membrane of the M cells and allow for transport of microbes and particles across the epithelial cell layer from the gut lumen to the lamina propria where interactions with immune cells can take place. Unlike their neighbor cells, M cells have the unique ability to take up antigen from the lumen of the small intestine via endocytosis, phagocytosis, or transcytosis. Antigens are delivered to antigen-presenting cells, such as dendritic cells, B lymphocytes. M cells express the protease cathepsin E, similar to other antigen-presenting cells; this process takes place in a unique pocket-like structure on their basolateral side. Antigens are recognized via expression of cell surface receptors such as glycoprotein-2 that detect and bind to bacteria.
Cellular prion protein is another example of a cell surface receptor on M cells. M cells lack microvilli but, like other epithelial cells, they are characterized by strong cell junctions; this provides a physical barrier that constitutes an important line of defense between the gut contents and the immune system of the host. Despite the epithelial barrier, some antigens are able to infiltrate the M cell barrier and infect the nearby epithelial cells or enter the gut. M cells are distinguished from other intestinal epithelial cells by their morphological differences, they are characterized by their short lack of these protrusions on the cell surface. When they present microvilli, they are short and present on the apical surface or pocket-like invagination on the basolateral surface of these cells; when they lack microvilli, they are characterized by their microfolds, hence receive their known name. These cells are far less abundant than enterocytes; these cells can be identified by cytoskeletal and extracellular matrix components expressed at the edge of cells or on their cell surfaces, such as actin, villin and vimentin.
Factors promoting the differentiation of M cells have yet to be elucidated, but they are thought to develop in response to signals from immune cells found in developing Peyer's patches. B cells have been implicated in the developmental of M cells, since they are localized in high numbers in the follicular-associated epithelium. FAE lacking B cell populations results in a decrease in the number of M cell lining the Peyer's patches. A human lymphoma cell line is known to undergo transition from adenocarcinoma cells to M cells. Though many studies have shown various cell types directing the differentiation of M cells, new research characterizes the molecular pathways that guide M cell differentiation. More through loss-of-function and rescue-phenotype studies, RANKL is shown to be a receptor activator of NF-κB ligand and play a role in differentiation of M cells. RANKL is expressed throughout the small intestine, facilitates uptake of pathogens such as Salmonella, is the most critical factor M cell differentiation.
Microbes found on intestinal epithelium are known to direct M cell development. For example, the type III secretion system effector protein SopB activates the transition of M cells from enterocytes. M cells undergo the differentiation process for up to four days before reaching full maturation. Recent studies have suggested they arise distinctly from the myeloid lineages. Pathogens can take advantage of cell differentiation pathways; this is done by inducing differentiation of enterocytes into M cell type in gut epithelium. In one case, the SopB effector protein mentioned above is secreted to trigger fast differentiation of enterocytes localized in the FAE by initiation of epithelial to mesenchymal transition in these cells; when SopB activates differentiation of enterocytes, it acts via the activation of the Wnt/b-catenin signaling pathway and triggers the RANKL and its receptor, implicated in regulating cell apoptosis. M cells do not secrete mucus or digestive enzymes, have a thinner glycocalyx, which allows them to have easy access to the intestinal lumen for endocytosis of antigens.
The main function of M cells is the selective endocytosis of antigens, transporting them to intraepithelial macrophages and lymphocytes, which migrate to lymph nodes where an immune response can be initiated. M cells play a role in passive immunity, or the transfer of active humoral immunity during and post pregnancy. Infants rely on antibodies specific to their mother's intestinal antigens, which move from the mother's gut and enter the breast milk; these antibodies are able to move into the milk supply through the lymphatic system. Though the mechanism of this transport is not understood, it is hypothesized that dendritic cells and macrophages play the role of transport vehicles. In females that are not lactating, when M cells recognize antigen in the gut, they stimulate production of many Immunoglobulin A antibodies; these antibodies are released into the gut mucosa, salivary glands, lymph nodes. However, in females that are lactating, M cells recognize antigen and IgA is directed from the gut to the mammary gland.
IgA traveling from the gut to breast milk supply is controlled by hormones and cytokines. Thus, the mammary gland and breast milk have critical roles alongside M cells in mucosal immune system. M cells are exploited by several pathogenic gram-negative bacteria including Shigella flexneri, Salmonella typhimurium, Yersinia pseudotuberculosis, as well as infectious prions, such as in bovine spongiform encephalitis (Mad