The Social Construction of Technology (SCOT) is a theory within the field of Science and Technology Studies (STS) that emphasizes the role of social factors in shaping technological development and use. This perspective posits that technology is not an independent force that shapes society, but rather that its development is influenced by social groups, cultural norms, economic interests, power dynamics, and political contexts.

AX.25 is a data link layer protocol widely used in amateur radio for packet radio communications. Developed in the 1970s by the American Radio Relay League (ARRL), AX.25 is designed for use over radio frequencies and provides a way for users to exchange data packets in a robust and efficient manner. Key features of AX.25 include: 1. **Packet Switching**: AX.

Michael Slote is an American philosopher known for his contributions to moral philosophy, particularly in the area of ethical theory. He has worked extensively on topics such as virtue ethics, sentimentalism, and the philosophy of emotions. Slote is also recognized for advocating a form of altruism that emphasizes empathic concern and emotional engagement in moral decision-making. He is associated with a contemporary approach to ethics that contrasts with more traditional, deontological and consequentialist theories.

2026-02-07: might have lost a the left North Face etip recycled gloves black with white signs, rebuying without too much thinking, redundancy is fine now that I'm old and don't have time: www.amazon.co.uk/dp/B08BDPDNH7

2025-12-28: after losing the Karrimor X Lite Run Black Headband for good going to try a few ones online:

2024-11: OK, I give up, going to try and find the Extremities XDRY again, as these are the perfect gloves for the UK. Buying www.amazon.co.uk/dp/B00OISFUQ4. Their marketing is very confusing and there are several different names for the product, but the label reads "extremities insulated waterpoof sticky power liner glove", black, large. This is the official page: www.terra-nova.co.uk/products/insulated-waterproof-sticky-power-liner-gloves X-Dry Stretch, 100% polyester.

2024-10: going to try Endura Men's Strike Glove - Hi-Viz Yellow, Large www.endurasport.com/strike-glove-hi-viz-yellow/12929542.html | www.wiggle.com/endura-strike-gloves-930526#colcode=93052613. These gloves are high quality, but they are too hot and fleecy for the UK, unless it is an exceptionally cold winter day around 0. This means that they get quite wet from sweat, and they are not that breathable. Also they are very hard to take off and put on, which is painful if you are like me who uses your cell phone for navigation, and while it works with touchscreens, sometimes it's just too annoying and you have to take them off.

2024-05: going to try www.sealskinz.com/products/water-repellent-all-weather-glove Sealskinz Tasburgh Water Repellent All Weather love black large because Extremities XDRY has a hole on right thumb due to gear shifting. This glove is very similar to the Nike academy hyperwam, not really a winter glove feels like. Weird branding...

2023-11: Endura Windchill Bibtights XL - Black: www.endurasport.com/windchill-bibtights-black/12926004.html because knees of dhb one open. I'm an idiot for getting XL... it's just that L felt too short on the top. But ultimately XL was too baggy, this became quite apparent on first usage, L would likely have been better, just would have needed to pull it a bit more. Quality is very good, very water repellent, kept me warm on 2C under very light rain. Also tried www.endurasport.com/xtract-bibtight-black/12926142.html but the sizing was completely different. L on that one as obviously too large, M felt correct.

2023-07: lost my waterproof cap, not cycling specialized, but was useful. Was by itself in crappy backpocket of cheap muddy fox jersey, lots of wind, some fence jumping... Hadn't noted know the brand/model... sad. Let's try Castelli A/C 2 Cycling Cap? www.castelli-cycling.com/US/en/Men/Collection/Hot-Weather-Kit/A-C-2-CYCLING-CAP/p/4523032_008 Single size. Slightly small, but hard to be sure.

2023-07: www.dhbsport.com/products/aeron-short-sleeve-jersey-2-0 dhb Aeron Short Sleeve Jersey 2.0 Colour Ink Blue Size (Standard) L. To prevent crap from falling again hopefully. Felt too small. Material: 100% polyester, inserts, 64% polyester, 6% elastane. Compared to the non 2.0 which I have, the material feels more glossy/slippery. Slightly weird.

2023-05: www.wiggle.com/p/dhb-classic-shorts?color=black&sizeStandard=M dhb Classic Shorts, medium.

2022-05: buying another "dhb Lightweight Mesh Long Sleeve Base Layer", small www.wiggle.com/p/dhb-lightweight-mesh-long-sleeve-base-layer. I notice that it is actually a bit not long enough. Doesn't make a huge difference, but maybe medium or large next time.

2022-12 Rohan Polar Gloves, black, large, 45 pounds. Shell: 85% polyamide, 15% elastane. Insulation: 100% polyester. 100g insulation on back of the hand. www.rohan.co.uk/mens/accessories-polar-gloves Let's see how they perform after hands were very cold on a bike ride with the Extremities XDRY.

2022-08 dhb Aeron Short Finger Gel Gloves 2.0 medium white www.wiggle.co.uk/dhb-aeron-short-finger-gel-gloves-20. For sun/fall protection. In theory should be small according to size guide, but small was over, and I have my doubts it is correct.

2021-12: bought a North Face etip recycled gloves black with white signs, large about 40 dollars: www.thenorthface.co.uk/shop/en-gb/tnf-gb/mens-etip-gloves-4sha?variationId=KY4 let's see how that goes. These ended up being very good. They are not very warm, good for 10-15 C maybe, which is a important range. Water performance is very good

2021-12:

2021-06: Castelli UPF 50+ Light Arm Sleeves (Skins) Large White, 29 pounds www.castelli-cycling.com/bg/upf-50-+-light-arm-sleeves/p/451603621P-001. Felt really good. Really does not trap much heat, and completely blocks off sun. It makes you develop a small layer of sweat that keeps you cool, cooler than without the sleeves.

2021-02 Castelli PRO THERMAL SKULLY red www.wiggle.co.uk/castelli-pro-thermal-skully www.castelli-cycling.com/gb/pro-thermal-skully/p/452054220A to help with cold, the X Lite Run Black Headband is just not made for winter.

2021-01: Madison Cycle Everywear Sportive Toe covers. L/XL. www.madison.cc/shop/sportive-thermal-toe-covers/VARCLA121/CLA12104

2021-01: "Endura FS260-NEMO Glove II" Neoprene Winter Handwarmer Large. www.endurasport.com/Gants-Nemo-FS260-Pro-II/p/E1216-Black Let's see how neoprene feels like. Basically it becomes wet with your transpiration, but is still relatively warm, would take it well down to 5C. Likely would work well with heavy rain. Not bad. But does feel a bit cooler than the Extremities XDRY, especially after you walk for a bit, and your hand becomes cold, and it is very hard to warm it because it is also wet.

2020-12-21: "dhb Neoprene Nylon Overshoes" www.wiggle.co.uk/dhb-neoprene-nylon-overshoes large black. After 2 rides, noticed that the front lower part of left foot (the one I put on and off the most) had a hole in it, not sure where it was made. Edit: I later noticed that it is because I have the reflex of braking slightly with my shoes in certain conditions, e.g. at lower speeds in close proximity to pedestrians, the sounds of which also serve as a way to alert them without the need for a loud bell. But it destroys the overshoe, so I have to undo that reflex.

2020-11-06 www.alpinetrek.co.uk/castelli-perfetto-ros-long-sleeve-cycling-jersey/ "Castelli Perfetto RoS Long Sleeve - Cycling jersey" size L Large. On Wiggle: www.wiggle.co.uk/castelli-perfetto-ros-long-sleeve-jersey Feels great. Together with the dhb Merino Long Sleeve Base Layer, I can gown down to 0 Celcius, no problem, and up to 14 with the "Mesh Long Sleeve Base Layer". Breathes great, blocks wind and rain reasonably, and can holds mild rain out on a short 1.5h ride without problem. I used this so much it is unbelievable.

2020-10-17:

For sizing see also: Ciro Santilli's body.

2020-11: Castelli Thermoflex 2 Arm Warmers, Large, 28 pounds: www.wiggle.co.uk/castelli-thermoflex-2-arm-warmers | www.castelli-cycling.com/gb/men/accessories/cycling-leg-and-arm-warmers/p/451953020A-010 advertized 8°-20°C. Was going to buy the DHB ones for 10 pounds less, but always out of so Castelli it is.

2020-08: started getting getting cold, so let's do it:

2020-05 www.wiggle.co.uk/dhb-aeron-short-sleeve-jersey-4/ dhb Aeron Short Sleeve Jersey 100% polyester, Red Large. This one fit OK. Length feels right. When on cycling position, a bit baggy under arms though, but guessing M would be too short? Still already feels less baggy than the cheap muddy fox jersey. Aeron is the second lowest level of DHB top, after the super basic 25 pound one. Material is thin polyester, could be better, but OK.

2020-05 www.wiggle.co.uk/castelli-perfetto-light-2-short-sleeve-jersey/ Castelli Perfetto Light 2 Short Sleeve Jersey 84% Nylon, 16% Lycra. When it arrived, was WAY too small, so returned. Material looked and felt amazing.

2019-12 www.wiggle.co.uk/dhb-merino-long-sleeve-base-layer-1/?sku=5360752872 "dhb Merino Long Sleeve Base Layer", black, small, was right size, wool is a bit itchy, but does feel like it dries off more quickly on long rides than the cheap Muddy Fox polyester cycling Jersey. Pretty warm, too much for 15C.

2019-12 www.wiggle.co.uk/dhb-aeron-winter-weight-merino-sock/?sku=100335580 dhb Aeron Winter Weight Merino Sock, blue, UK 9.5-12. Did not seem to make much of a difference, feet still cold, not wet.

2019-11 Nike academy hyperwarm gloves: www.nike.com/gb/t/hyperwarm-academy-football-gloves-s9Dd8D/GS0373-013 (archive) for 17.99 Pounds from physical retailer. Good intermediate between the Extremities gloves when it gets a bit warmer. 60% polyester/27% nylon/5% rubber/4% elastane.

2019-10 XGC Men's Cycling Shorts/Bike Shorts And Cycling Underwear With High-Density High-Elasticity And Highly Breathable 4D Sponge Padded www.amazon.co.uk/dp/B07BDJP64W (archive). Grey color, red inner butt padding. 2020-08: after using it a lot, noticed that the padding stiches started to come off a bit.

2018 (?) Extremities XDRY gloves Looks like: www.sportsdirect.com/extremities-wp-p/line-glove-91-907293 (archive) Gets wet after a few minutes of medium rain. But does dry quickly. Baggy, multilayer. Says 40 pounds, but always at 20 pound discount, so it is just a marketing trick. On website: Outershell 96% Polyester/4% Lycra (Spandex)Palm 45% Polyester/55% PolyurethaneLining 100% Polyester

2017-09 Trespass Cruzado Male Gloves size S. www.trespass.com/cruzado-unisex-gloves (archive) Markings: crossover gloves. Technical Performance TP75: www.trespass.com/advice/trespass-tp-ratings-guide/ Lost right hand around 2018/2019.

2017 Muddy fox cycling Jersey, orange, polyester, Large, cheap. Works well enough I guess. Could be a bit more tight fitting.

2017 www.amazon.co.uk/Nevica-Unisex-Reversible-Skuff/dp/B07GSD4R7Y Nevica Skuff black

2017 www.ebay.co.uk/itm/254646634761 Karrimor X Lite Run Black Headband. Had a hole in the ear for a long time. Miraculously surived being almost lost on several occasions, including once it fell off from bike and a dude coming behind pointed it to me. But then alas on 2025-12-28 I lost it, noticed next day wasn't there, by chance found it on neighboring park, but it had been torn very badly, a dog must have done that, so I had to throw it away!

2015 UNIQLO tights 53% cotton, 32% polyester, 15% elastane. 2020-08: after riding it a lot, it ripped a bit near upper inner tights.

2015 Odlo top and tights, polyester. Not sure exact model, not necessarily meant for cycling. Top does not fit tightly, did not feel like it was removing sweat effectively.

As per en.wikipedia.org/w/index.php?title=Semidirect_product&oldid=1040813965#Properties, unlike the Direct product, the semidirect product of two goups is neither unique, nor does it always exist, and there is no known algorithmic way way to tell if one exists or not.

This is because reaching the "output" of the semidirect produt of two groups requires extra non-obvious information that might not exist. This is because the semi-direct product is based on the product of group subsets. So you start with two small and completely independent groups, and it is not obvious how to join them up, i.e. how to define the group operation of the product group that is compatible with that of the two smaller input groups. Contrast this with the Direct product, where the composition is simple: just use the group operation of each group on either side.

Product of group subsets

So in other words, it is not a function like the Direct product. The semidiret product is therefore more like a property of three groups.

The semidirect product is more general than the direct product of groups when thinking about the group extension problem, because with the direct product of groups, both subgroups of the larger group are necessarily also normal (trivial projection group homomorphism on either side), while for the semidirect product, only one of them does.

Conversely, en.wikipedia.org/w/index.php?title=Semidirect_product&oldid=1040813965 explains that if $G=N⋊H$, and besides the implied requirement that N is normal, H is also normal, then $G=N\times H$.

Smallest example: $D_6=C_3⋊C_2$ where $D$ is a dihedral group and $C$ are cyclic groups. $C_3$ (the rotation) is a normal subgroup of $D_6$, but $C_2$ (the flip) is not.

Note that with the Direct product instead we get $C_6$ and not $D_6$, i.e. $C_3\times C_2=C_6$ as per the direct product of two cyclic groups of coprime order is another cyclic group.

TODO:

Bibliography: math.stackexchange.com/questions/1726939/is-this-intuition-for-the-semidirect-product-of-groups-correct

Often just called collimated light due to the collimator being the main procedure to obtain it.

However, you move very far away from the source, e.g. the Sun, you also get essentially parallel light.

Bibliography:

Given the view of the Standard Model where the electron and quarks are just completely separate matter fields, there is at first sight no clear theoretical requirement for that.

As mentioned e.g. at QED and the men who made it: Dyson, Feynman, Schwinger, and Tomonaga by Silvan Schweber (1994) chapter 1.6 "Hole theory", Dirac initially wanted to think of the holes in his hole theory as the protons, as a way to not have to postulate a new particle, the positron, and as a way to "explain" the proton in similar terms. Others however soon proposed arguments why the positron would need to have the same mass, and this idea had to be discarded.

The Dirac equation can be derived basically "directly" from the Representation theory of the Lorentz group for the spin half representation, this is shown for example at Physics from Symmetry by Jakob Schwichtenberg (2015) 6.3 "Dirac Equation".

The Diract equation is the spacetime symmetry part of the quantum electrodynamics Lagrangian, i.e. is describes how spin half particles behave without interactions. The full quantum electrodynamics Lagrangian can then be reached by adding the $U(1)$ internal symmetry.

As mentioned at spin comes naturally when adding relativity to quantum mechanics, this same method allows us to analogously derive the equations for other spin numbers.

Bibliography:

Allows you to connect two adjacent pins of a pin header. Sometimes used as a hardware configuration interface!