#topic6

[fath-k]

Topic 6: Servers (CN)

List all the different types of specialist server you can think of or find via the Internet and books (e.g. mail server). Briefly describe each one.

Application Servers - An application server is a program that handles all application operations between users. It is a server program in a computer in a distributed network that provides the business logic for an application program.

Communication Server – It is a dedicated system that provides communication services for users on a network who need to transfer files or access information on systems or networks at remote locations over telecommunication links.

Domain Controllers/Directory Servers – It is a server that responds to security authentication requests within a Windows Server domain. 

Fax Servers – It is a system installed in a local area network (LAN) server that allows computer users who are attached to the LAN to send and receive fax messages. 

File Servers – It is a computer responsible for the central storage and management of data files so that other computers on the same network can access the files.

Print Servers – It is a software application, network device or computer that manages print requests and makes printer queue status information available to end users and network administrators.

Mail Servers – It is an application that receives incoming e-mail from local users (people within the same domain) and remote senders and forwards outgoing e-mail for delivery.

Web Servers – It is a program that uses HTTP (Hypertext Transfer Protocol) to serve the files that form Web pages to users, in response to their requests, which are forwarded by their computers' HTTP clients.

References

Webopedia.com. (2017). What is Application Server? Webopedia Definition. [online] Available at: http://www.webopedia.com/TERM/A/application_server.html [Accessed 23 May 2017].

Linktionary.com. (2017). Communication Server (Linktionary term) . [online] Available at: http://www.linktionary.com/c/comm_server.html [Accessed 23 May 2017].

Techopedia.com. (2017). What is a Domain Controller? - Definition from Techopedia. [online] Available at: https://www.techopedia.com/definition/4193/domain-controller [Accessed 23 May 2017].

WhatIs.com. (2017). What is fax server? - Definition from WhatIs.com. [online] Available at: http://whatis.techtarget.com/definition/fax-server [Accessed 23 May 2017].

SearchNetworking. (2017). What is file server? - Definition from WhatIs.com. [online] Available at: http://searchnetworking.techtarget.com/definition/file-server [Accessed 23 May 2017].

WhatIs.com. (2017). What is print server? - Definition from WhatIs.com. [online] Available at: http://whatis.techtarget.com/definition/print-server [Accessed 23 May 2017].

SearchMicroservices. (2017). What is mail server (mail transfer/transport agent, MTA, mail router, Internet mailer)? - Definition from WhatIs.com. [online] Available at: http://searchmicroservices.techtarget.com/definition/mail-server-mail-transfer-transport-agent-MTA-mail-router-Internet-mailer [Accessed 23 May 2017].

WhatIs.com. (2017). What is Web server? - Definition from WhatIs.com. [online] Available at: http://whatis.techtarget.com/definition/Web-server [Accessed 23 May 2017].

[msagostino]

How does the digestive system work?

In this activity students created a working model of the digestive system using various household items like sponges, cups, pantyhose etc...The students were given a bin full of items and had to justify why each item represented a different organ based on its structure and function. They then created a video to explain how the model worked and posted it on Vialogues. They then commented on each other’s videos and posted questions to continue the discussion.

[hellenicroundtable]

RoundTable Topic 6

Sorry for being a day late again this month guys! The days got messed up in my head. ANYWAY the topic for this month is

Everyone has dry spells in their religious practices. How do you handle the fallow times in your religious practice?

As always please tag this blog in your posts and I’m tracking hellenicroundtable, hellenicrt, hellenic round table and topic6 as tags!

[bitalks]

Hey folks!

Just a reminder that we're currently talking about bisexuality & asexuality. We love reading all of your experiences and thoughts about the intersection of these two identities. I hope those of you who haven't posted yet, will have time to do so soon!

Also, note that this topic will be closing this weekend, Saturday, Nov 8 (instead of Nov 15 as previously announced).

- Noodle

[ib-biology-optione]

Neuro in Topic 6

This is a summary of the neuro content in Topic 6: Human health and physiology "6.5.1 State that the nervous system consists of the central nervous system (CNS) and peripheral nerves, and is composed of cells called neurons that can carry rapid electrical impulses. The nervous system consists of the central nervous system (CNS) and peripheral nerves, and is composed of cells called neurons which carry rapid electrical impulses. 6.5.2 Draw and label a diagram of the structure of a motor neuron.

6.5.3 State that nerve impulses are conducted from receptors to the CNS by sensory neurons, within the CNS by relay neurons, and from the CNS to effectors by motor neurons. Nerve impulses are conducted from receptors to the CNS by sensory neurons, within the CNS by relay neurons, and from the CNS to effectors by motor neurons. 6.5.4 Define resting potential and action potential (depolarization and repolarization). Resting potential: the electrical potential across the plasma membrane of a cell that is not conducting an impulse. Action potential: the reversal and restoration of the electrical potential across the plasma membrane of a cell, as an electrical impulse passes along it (depolarization and repolarization). 6.5.5 Explain how a nerve impulse passes along a non-myelinated neuron. Sodium is found in greater concentrations outside of the cell while potassium is found in greater concentrations inside the cell. Sodium-potassium pumps exist in the plasma membrane to maintain the the concentration gradients and the membrane potential. Nerve impulses have a domino effect. An action potential in one part of the neuron causes another action potential in the adjacent part and so on. This is due to the diffusion of sodium ions between the region of the action potential and the resting potential. It is the movement of sodium and potassium that reduce the resting potential. If the resting potential rises above the threshold level, voltage gated channels open. Voltage gated sodium channels open very fast so that sodium can diffuse into the cell down its concentration gradient. This reduces the membrane potential and results in more sodium channels opening. Sodium ions are positively charged and so the inside of the cell develops a net positive charge compared to the outside of the cell. This results in depolarization as the potential across the membrane is reversed. A short while after this, voltage gated potassium channels open and potassium ions flow out of the cell down the concentration gradient. Since potassium ions are positively charged, their diffusion out of the cell causes a net negative charge to develop again inside the cell compared to the outside. The potential across the membrane is restored. This is called repolarization. Finally, the concentration gradients of both ions are restored by the sodium-potassium pump. Sodium is pumped out of the cell while potassium is pumped in. The resting potential is restored and the neuron is ready to conduct another nerve impulse. Summary: 1.Resting potential rises above threshold level. 2.Voltage gated sodium channels open. 3.Sodium ions flow into the cell, more sodium channels open. 4.Inside of cell develops a net positive charge compared to the outside and results in depolarization. 5.Voltage gated potassium channels open. 6.Potassium ions flow out of the cell. 7.Cell develops a net negative charge compared to the outside and results in repolarization. 8.Concentration gradients restored by sodium-potassium pumps. 9.Resting potential is restored. 6.5.6 Explain the principles of synaptic transmission. A synapse is a junction that permits a neuron to pass an electrical or chemical signal to another cell. At a synapse, the plasma membrane of the signal passing neuron (presynaptic neuron) is closely related to the plasma membrane of the target cell (postsynaptic neuron). Between the two there is a narrow fluid filled space called the synaptic cleft. Chemical signals called neurotransmitters pass from the presynaptic neuron to the post synaptic neuron. This is how a synaptic transmission occurs: An action potential travels along the neuron and reaches the end of the pre-synaptic neuron. The depolarization of the pre-synaptic membrane results in the opening of voltage gated calcium channels. Calcium ions flow into the presynaptic neuron and cause vesicles with neurotransmitters inside the neuron to fuse with the plasma membrane and release the neurotransmitters into the synaptic cleft via exocytosis. These neurotransmitters then diffuse within the synaptic cleft and some will bind to specific receptors located on the postsynaptic plasma membrane. The receptors are transmitted-gated ion channels which open and let sodium and other positively charged ions into the postsynaptic neuron when the neurotransmitters bind. As these positively charged ions enter the postsynaptic neuron they cause its membrane to depolarize. This depolarization results in an action potential which passes down the postsynaptic neuron. The neurotransmitters in the synaptic cleft are then quickly degraded and the calcium ions are pumped back into the synaptic cleft from inside the presynaptic neuron.

Summary: 1.Action potential reaches the end of a presynaptic neuron. 2.Voltage gated calcium channels open. 3.Calcium ions flow into the presynaptic neuron. 4.Vesicles with neurotransmitters inside the presynaptic neuron fuse with the plasma membrane. 5.Neurotransmitters diffuse in the synaptic cleft and bind to receptors on the postsynaptic neuron. 6.The receptors are channels which open and let sodium ions into the postsynaptic neuron. 7.The sodium ions cause the postsynaptic membrane to depolarize. 8.This causes an action potential which passes down the postsynaptic neuron. 9.Neurotransmitters in the synaptic cleft are degraded and the calcium ions are pumped back into the synaptic cleft." From source # 1

[msagostino]

How are nerve impulses transmitted?

Students used whiteboards and beads to model the movement of ions across the membrane of an axon. This activity was done after students had already explored the nerve impulse through an interactive MOODLE lesson that included quizzes, screencasts and animations. It was used to formatively assess the students' understanding and their ability to communicate that understanding.

[msagostino]

How do we breathe?

Students created a working ventilation system out of a plastic bottle, balloons, straws and tape. This activity helped debunk a misconception that air is "sucked in" through the nose and helped explain the mechanics of breathing via volume and pressure changes in the thorax.