Is the swine flu scare worth complete isolation if possible?
Right now it's not that big of a deal, but it very well could turn into one. I think your husband is smart to go out and get a food storage supply. We just went out yesterday and stocked up on canned goods, pastas, meats for the freezer, etc. so that if necessary we could eat comfortably for a few months. It may not be because we want to isolate ourselves, but if the country gets into a state of panic there might be a lot of things that are not even available! Stock up on masks and hand sanitizer, those will be the first to go. I do not plan to isolate our family, but if that became necessary I would rather be prepared than not. Things can get out of hand quickly because of panic even if the panic is not necessary.
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Question Regarding Isolation and Limit Points
No. Or, more accurately, yes, but the thing you wrote after "my question is" is not the same as the definition: for a point $p$ to be a limit point of a set $S$, every neighbourhood of $p$ must contain some element of $S setminus p$. It is then easy to see that not all points have this property: for example, for any $p in mathbbZ$, there is no point of $mathbbZ$ in the neighbourhood $(p - 1, p 1)$ of $p$
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What should I do? I have a 4 year old and a 3 month old. I am feeling lost regarding my parenting. I feel I have made a mistake by having a second child.
Speak to a counsellor; speak to other mothers; speak to your partner, your family, your friends. Do not worry in isolation. Remember the kids are relying on you. Get help, stay strong. Good luck
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Is isolating myself the best thing to do?
Do what you want. You will NOT make it through any hardcore training without a buddy
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Electronic equipment and signal and power transmission lines can be subjected to voltage surges induced by lightning, electrostatic discharge, radio frequency transmissions, switching pulses (spikes) and perturbations in power supply. Remote lightning strikes can induce surges up to 10 kV, one thousand times more than the voltage limits of many electronic components. A circuit can also incorporate high voltages by design, in which case it needs safe, reliable means of interfacing its high-voltage components with low-voltage ones. The main function of an opto-isolator is to block such high voltages and voltage transients, so that a surge in one part of the system will not disrupt or destroy the other parts. Historically, this function was delegated to isolation transformers, which use inductive coupling between galvanically isolated input and output sides. Transformers and opto-isolators are the only two classes of electronic devices that offer reinforced protection - they protect both the equipment and the human user operating this equipment. They contain a single physical isolation barrier, but provide protection equivalent to double isolation. Safety, testing and approval of opto-couplers are regulated by national and international standards: IEC 60747-5-2, EN (CENELEC) 60747-5-2, UL 1577, CSA Component Acceptance Notice #5, etc. Opto-isolator specifications published by manufacturers always follow at least one of these regulatory frameworks. An opto-isolator connects input and output sides with a beam of light modulated by input current. It transforms useful input signal into light, sends it across the dielectric channel, captures light on the output side and transforms it back into electric signal. Unlike transformers, which pass energy in both directions[note with very low losses, opto-isolators are unidirectional (see exceptions) and they cannot transmit power. Typical opto-isolators can only modulate the flow of energy already present on the output side. Unlike transformers, opto-isolators can pass DC or slow-moving signals and do not require matching impedances between input and output sides.[note Both transformers and opto-isolators are effective in breaking ground loops, common in industrial and stage equipment, caused by high or noisy return currents in ground wires. The physical layout of an opto-isolator depends primarily on the desired isolation voltage. Devices rated for less than a few kV have planar (or sandwich) construction. The sensor die is mounted directly on the lead frame of its package (usually, a six-pin or a four-pin dual in-line package). The sensor is covered with a sheet of glass or clear plastic, which is topped with the LED die. The LED beam fires downward. To minimize losses of light, the useful absorption spectrum of the sensor must match the output spectrum of the LED, which almost invariably lies in the near infrared. The optical channel is made as thin as possible for a desired breakdown voltage. For example, to be rated for short-term voltages of 3.75 kV and transients of 1 kV/s, the clear polyimide sheet in the Avago ASSR-300 series is only 0.08 mm thick. Breakdown voltages of planar assemblies depend on the thickness of the transparent sheet and the configuration of bonding wires that connect the dies with external pins. Real in-circuit isolation voltage is further reduced by creepage over the PCB and the surface of the package. Safe design rules require a minimal clearance of 25 mm/kV for bare metal conductors or 8.3 mm/kV for coated conductors. Opto-isolators rated for 2.5 to 6 kV employ a different layout called silicone dome. Here, the LED and sensor dies are placed on the opposite sides of the package; the LED fires into the sensor horizontally. The LED, the sensor and the gap between them are encapsulated in a blob, or dome, of transparent silicone. The dome acts as a reflector, retaining all stray light and reflecting it onto the surface of the sensor, minimizing losses in a relatively long optical channel. In double mold designs the space between the silicone blob ("inner mold") and the outer shell ("outer mold") is filled with dark dielectric compound with a matched coefficient of thermal expansion.