Health policy

Health policy can be defined as the "decisions, plans, and actions that are undertaken to achieve specific health care goals within a society." According to the World Health Organization, an explicit health policy can achieve several things: it defines a vision for the future; it outlines priorities and the expected roles of different groups; and it builds consensus and informs people.



There are many categories of health policies, including personal health care policy, pharmaceutical policy, and policies related to public health such as vaccination policy, tobacco control policy or breastfeeding promotion policy. They may cover topics of financing and delivery of health care, access to care, quality of care, and health equity.

There are also many topics in the politics and evidence that can influence the decision of a government, private sector business or other group to adopt a specific policy. Evidence-based policy relies on the use of science and rigorous studies such as randomized controlled trials to identify programs and practices capable of improving policy relevant outcomes. Most political debates surround personal health care policies, especially those that seek to reform health care delivery, and can typically be categorized as either philosophical or economic. Philosophical debates center around questions about individual rights, ethics and government authority, while economic topics include how to maximize the efficiency of health care delivery and minimize costs.

Illness

Illness (sometimes referred to as ill-health or ailment) is a state of poor health. Illness is sometimes considered another word for disease. Others maintain that fine distinctions exist. Some have described illness as the subjective perception by a patient of an objectively defined disease.

The mode of being healthy includes, as defined by the World Health Organization, " [...] a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity". When these conditions are not fulfilled, then one can be considered to have an illness or be ill. Medication and the science of pharmacology is used to cure or reduce symptoms of an illness or medical conditions. Developmental disability is a term used to describe severe, life-long disabilities attributable to mental and/or physical impairments.

Physical

Conditions of the body or mind that cause pain, dysfunction, or distress to the person afflicted or those in contact with the person can be deemed an illness. Sometimes the term is used broadly to include injuries, disabilities, syndromes, infections, symptoms, deviant behaviors, and atypical variations of structure and function, while in other contexts these may be considered distinguishable categories. A pathogen or infectious agent is a biological agent that causes disease or illness to its host. A passenger virus is a virus that simply hitchhikes in the body of a person or infects the body without causing symptoms, illness or disease. Foodborne illness or food poisoning is any illness resulting from the consumption of food contaminated with pathogenic bacteria, toxins, viruses, prions or parasites.

Adaptive response

According to evolutionary medicine, much illness is not directly caused by an infection or body dysfunction but is instead a response created by the body. Fever, for example, is not caused directly by bacteria or viruses but by the body raising its normal human body temperature, which some people believe inhibits the growth of the infectious organism. Evolutionary medicine calls this set of responses sickness behavior. These include such illness defining health changes as lethargy, depression, anorexia, sleepiness, hyperalgesia, and the inability to concentrate. These together with fever are caused by the brain through its top down control upon the body. They are, therefore, not necessary, and often do not accompany an infection (such as the lack of fever during malnutrition or late pregnancy) when they have a cost that outweighs their benefit. In humans, an important factor are beliefs that influence whether the health management system in the brain that evaluates costs and benefits deploys them or not. The health management system, when it factors in false information, has been suggested to underlie the placebo reduction of illness.[8]

Mental

Mental illness (or Emotional disability, Cognitive dysfunction) is a broad generic label for a category of illnesses that may include affective or emotional instability, behavioral dysregulation, and/or cognitive dysfunction or impairment. Specific illnesses known as mental illnesses include major depression, generalized anxiety disorder, schizophrenia, and attention deficit hyperactivity disorder, to name a few. Mental illness can be of biological (e.g., anatomical, chemical, or genetic) or psychological (e.g., trauma or conflict) origin. It can impact one’s ability to work or go to school and contribute to problems in relationships. Other generic names for mental illness include “mental disorder”, “psychiatric disorder”, “psychological disorder”,“abnormal psychology”, “emotional disability”, “emotional problems”, or “behavior problem”. The term insanity is used technically as a legal term. Brain damage may result in impairment of mental function.
[edit] Study of illness

Epidemiology is the scientific study of factors affecting the health and illness of individuals and populations, and serves as the foundation and logic of interventions made in the interest of public health and preventive medicine.

Behavioral medicine is an interdisciplinary field of medicine concerned with the development and integration of psychosocial, behavioral and biomedical knowledge relevant to health and illness. Clinical Global Impression scale to assess treatment response in patients with mental disorders. It's " Improvement scale" requires the clinician to rate how much the patient's illness has improved or worsened relative to a baseline state. Mental confusion and decreased alertness may indicate that a chronic illness has gotten worse.

Disease

A disease is an abnormal condition affecting the body of an organism. It is often construed to be a medical condition associated with specific symptoms and signs.[1] It may be caused by external factors, such as infectious disease, or it may be caused by internal dysfunctions, such as autoimmune diseases. In humans, "disease" is often used more broadly to refer to any condition that causes pain, dysfunction, distress, social problems, and/or death to the person afflicted, or similar problems for those in contact with the person. In this broader sense, it sometimes includes injuries, disabilities, disorders, syndromes, infections, isolated symptoms, deviant behaviors, and atypical variations of structure and function, while in other contexts and for other purposes these may be considered distinguishable categories. Diseases usually affect people not only physically, but also emotionally, as contracting and living with many diseases can alter one's perspective on life, and their personality.

Death due to disease is called death by natural causes. There are four main types of disease: pathogenic disease, deficiency disease, hereditary disease, and physiological disease.

Diseases can also be classified as communicable and non-communicable disease.

Health Care

Health care (or healthcare) is the diagnosis, treatment, and prevention of disease, illness, injury, and other physical and mental impairments in humans. Health care is delivered by practitioners in medicine, chiropractic, dentistry, nursing, pharmacy, allied health, and other care providers. It refers to the work done in providing primary care, secondary care and tertiary care, as well as in public health.

Access to health care varies across countries, groups and individuals, largely influenced by social and economic conditions as well as the health policies in place. Countries and jurisdictions have different policies and plans in relation to the personal and population-based health care goals within their societies. Health care systems are organizations established to meet the health needs of target populations. Their exact configuration varies from country to country. In some countries and jurisdictions, health care planning is distributed among market participants, whereas in others planning is made more centrally among governments or other coordinating bodies. In all cases, according to the World Health Organization (WHO), a well-functioning health care system requires a robust financing mechanism; a well-trained and adequately-paid workforce; reliable information on which to base decisions and policies; and well maintained facilities and logistics to deliver quality medicines and technologies.

Health care can form a significant part of a country's economy. In 2008, the health care industry consumed an average of 9.0 percent of the gross domestic product (GDP) across the most developed OECD countries. The United States (16.0%), France (11.2%), and Switzerland (10.7%) were the top three spenders.

Health care is conventionally regarded as an important determinant in promoting the general health and wellbeing of peoples around the world. An example of this is the worldwide eradication of smallpox in 1980—declared by the WHO as the first disease in human history to be completely eliminated by deliberate health care interventions.

Chapter 1. Computer System Overview

Chapter 1. Computer System Overview

Intruction Execution

A program to be execute by a processor consists of a set of instruction stored in memory. In its simplest form, instruction processing of two: the processor reads (fetches) intructions from memory one at a time and executes each instruction. Program execution consists of repeating the process of instruction fetch and instruction execution. The instruction execution may involve several opeartions and depend s on the nature of the instruction.

The processing requered for a single instruction is colled an instruction cycle. Using the simplified two-step description, the instruction cycle is depicted in Figure 1.2. the two steps are referred to as the fetch stage and the execute stage. Program execution halts only if the machine is turned off, some sort of unrecoverable error occurs, or a program instruction that halts the processor is encountered.


Figure 1.2. Basic Instructino Cycle

Instruction Computer

Instruction fetch: take instruction from program storage
Instruction decode: determining the required actions and instruction size
Operand fetch: get and put operand
Execute: Obtain and put operand
Result store: calculate the value of the outcome or status
Next instruction: determining the next instruction

The processor interprets the instruction and performs the required action. In general, these actions fall into your categories.

1. Processor memory : data may be transferred from processor to memory or from memory to processor.
2. Processor I/O : Data may be transferred to or from a peripheral device by transferring between the processor and an I/O module.
3. Data processing : the processor may perform some arithmetic or logic operation on data.
4. Control : An instruction may specify that the sequence of execution be altered.

Source :
William Stallings, “Operating Systems “Internals and Design Principles”, Fifth Edition, Pearson Education Internationl
Related Post :
Basic Elements
Processor Register
Intruction Execution
Interupts
The Memory Hierarchycal
Cace Memory
I/O Communication
Recommended Reading and Web Sites

Chapter 1. Computer System Overview

Chapter 1. Computer System Overview

Processor Register
A processor includes a set of register that provides a type of memory that is faster and smaller than main memory. The register in the processor serve two functions:
1. User Visible Registers
A user visible register may be referenced by means of the machine language that the processor executes and is generally available to all programs, including application programs as well as system program. Types of register that are typically available are data, address, and condition code registers.

Data Registers
Can be assigned to a variety of functions by the programmer. In come case, they are general purpose in nature and can be used with any machine instruction that performs operations on data. Often, however, there are restrictions. For example, there may be dedicated registers for floating-point operations and others for integer operations.

Address Registers
Contain main memory addresses of data and instructions, or they contain a partion of the address that is used in the calculation of the complete or effective address. These register may themselves be general purpose, or may be devoted to a particular way, or mode, of addressing memory. Examples include the following :

Index register
Index addressing is a common mode of addressing that involves adding an index to a base value to get the effective address.

Segment register
With semented addressing, memory is divided into segments, wicht are variable-length block of words.

Stack pointer
If there is user-visible stack addressing, then there is a dedicated register that points to the top of the stack.
2. Control and status register
A variety of processor registers are employed to control the operation of the processor. On most machines, most of these are not visible to the user. Some of the may be accesible by machine instructions executed in what is referred to as a control or operating system modes.

Of course,, different will have different register organizations and use different terminology. We provide here a reasonably complete list of register types, with a brief description.

1. Program Counter (PC) : Contains the address of the next to be fetched.
2. Instruction register (IR) : Contains the instruction most recently fetched.

Source :
William Stallings, “Operating Systems “Internals and Design Principles”, Fifth Edition, Pearson Education Internationl
Related Post :
Basic Elements
Processor Register
Intruction Execution
Interupts
The Memory Hierarchycal
Cace Memory
I/O Communication
Recommended Reading and Web Sites

Chapter 1. Computer System Overview

Chapter 1. Computer System Overview

An Operating system exploits the hardware resources of one or more processor to provide a set of services to system users. The operating system also manages secondary memory and I/O (input/output) devices on behalf of its users. Accordingly, it is important to have some understanding of the undelying computer system hardware we begin our examination of operating system.

Basic Elements

At top level, a computer consists of processor, memory, and I/O component with one or more modules of each type. These components are interconnected in some fashion to achieve the main function of the computer, which is to execute programs. Thus there are four main structural elements:

1. Processor : Controls the operating of the computer and performs its data processing function. When there is only one processor, it is often referred to as the central processing unit (CPU).
2. Main Memory: Stores data and programs. This memory is typically volatile; that is, when the computer is shut down, the contenst of the memory are lost. In contrast, the contents of disk memory are reatined even when the computer system is shutdown. Main memory is also referred to as real memory or primary memory.
3. I/O Moduls : Move data between the computer and its external environment. The external environtment consists of a variety of devices, including secondary memory devices, communications equipment, and terminals.
4. System bus L Provides for communication among processor, main memory, and I/O Modules.



Figure 1.1. Computer Components

One of the processor’s function is to exchange data with memory. For this purpose, it typically makes use of two internal (to the processor) register: a memory addres register (MAR(, whitch specifies the address in memory for the next read or write; and a memory buffer register (MBR), which contains the data to be written into memory or which receives the data read from memory. Similarly, an I/O address register (I/OAR) specifies a particular I/O device. An I/O buffer register (I/OBR) is used for the exchange of data between an I/O module and the Processor.

A memory module consists of a set of locations, defined by sequentially numbered addresses. Each location contains a bit pattern that can be interpreted as either an instruction or data. An I/O module transfers data from external devices to processor and memory, and vice versa. It contains internal buffers for temporrarily holding data until can be sent on.

Source :
William Stallings, “Operating Systems “Internals and Design Principles”, Fifth Edition, Pearson Education Internationl
Related Post :
Basic Elements
Processor Register
Intruction Execution
Interupts
The Memory Hierarchycal
Cace Memory
I/O Communication
Recommended Reading and Web Sites