GPS location Date/Time:12/30/2012 20:03:26 GST
Climbing in Spain!
Escalando en España!
GPS location Date/Time:12/30/2012 20:03:26 GST
Climbing in Spain!
Escalando en España!
GPS location Date/Time:12/27/2012 20:29:29 GST
Paragliding in Spain!
Parapente en España!
We can discuss for hours how to prevent of sickness from appearing during our expeditions. From allergic reactions, to gastric infections and diarrhea, constipation, cold, Khumbu cough, blocked nose, eye dryness and infections, ear infections, gynecological problems, insect bites, blisters, cuts and small traumas. These are the most common heath issues you are most likely to experience during the course of any expedition, but on high altitude climbing the real challenge is how to prevent and fight altitude related illnesses, such as Acute Mountain Sickness (AMS).
There is a long list of places in the Internet where to find information on how to build a first aid kit, but I found quite difficult to find a comprehensive list of what to include in the kit for high altitude expeditions. During most of the big climbs I’ve done, I relied on my basic first aid kit for generic health issues such as most of the things mentioned in my previous line. For my biggest challenge ever, Khan Tengri 2012 Expedition, I had the same kit with extra medicines, and for high altitude sickness I relied on the big medical kit we carried as a team during the expedition. This, when I see it retrospectively, is a mistake for two reasons. A communal medical kit might not have enough supplies for several climbers falling ill during the course of the same expedition. And secondly, you might have unexpected reaction to some of the drugs included in the kit. During that expedition we were lucky to have two doctors in the climbing team, but most of the times you have to rely in your or someone else’s knowledge when fighting sickness. In big and complex commercial expeditions, such as the ones carried out to the eight thousanders, medical consultancy is included or available as basecamp service. However you should not expect the yaks to carry up a whole pharmacy. In places like the Khumbu Valley in Nepal is not difficult to find doctors climbing or working in some of the most transited villages. However they are not always are fully stocked with drugs and they must charge you accordingly. Bring your own kit and you’ll be better prepared to fight illness and make it to the summit and back home safe and happy.
This post contains a list of things to include in your personal medical kit / first aid kit. It is highly advisable to go through the list with your doctor and make sure none of the medicines are contraindicated considering your medical history and current condition. You should get guidance on how to administer each medicine and carry instruction written in a piece of paper stored in the kit. In certain circumstances you might be unable to think clearly, and these instructions should be easy to read and understand by you or your climbing partners. Some directions on the dose are included here, but all this information is to be carefully reviewed and discussed with your doctor. This list is designed for someone very healthy like me (thanks god!), and it does not consider certain pre-existing conditions such as diabetes, asthma, epilepsy, allergies, high blood pressure, etc.
For certain destinations some of the medicines can get you into legal issues, so it worth investigating that in advance, and carrying a letter from the doctor if necessary.
I have divided the list in two sections. The first one contains things that must be included in the kit as bare minimum, it’s the kit you must carry with you at all times to cope with emergencies. The second contains a list of extra things that will help you fighting other common illnesses and will make your trip more pleasant by helping with minor issues.
Other important things to bring and make sure we are protected against external factors that produce health issues are
You can also purchase one First Aid Kit designed for outdoor activities, such us the Lifesystems Mountain First Aid Kit and complement it with some of the things listed in this post.
Basic Lifesystems First Aid Kit with some additions and the extra kit with essential things such as the emergency condom.
Lifesystems products are distributed in UAE by Global Climbing, the main distributor of outdoor adventure brands in the Middle East. Global Climbing is also the regional representative of Walltopia climbing walls and HRT, two of the worlds largest and most innovative companies working with artificial climbing structures.
All products distributed by Global Climbing can be found in many places in Dubai, but the one shop stop for outdoor enthusiast is Adventure HQ. Located at Dubai’s Times Square Centre, it is the ultimate destination for outdoor adventure gear.
Visit your doctor at least six months before you leave for your expedition, get a blood test done to make sure you are doing fine with things like glucose and iron levels, which can seriously affect hemoglobin saturation and oxygen delivery at high altitude. Have a full dental check and cleaning done before departure, a minor dental problem at sea level can become a serious issue in a long high altitude expedition. If you suffer from eye dryness like I do, I recommend you to visit your ophthalmologist one week before departure to have you eye lids and tear ducts cleaned. That prevents the awkward dryness and ophthalmological issues from appearing. I did that before my last expedition and I climbed with fresh eyes and no bothering during the whole trip.
Make everybody aware of your medical conditions, the symptom and treatment. Your illness could become a risk for everyone in your group. If you need especial medication make clear labels and instructions, have spare supplies and split the kit to lower the chance of losing it all. Ask your doctor to prepare an official letter, explaining your condition, treatment and contact details.
Get first aid training for you and your climbing partners. Make sure they know about AMS and how to treat it. Think about what you will do if things go wrong
Consult with you travel nurse about vaccinations and make sure these are not contraindicated for high altitude climbing.
BE HONEST WITH EVERYONE ABOUT CHANGES IN YOUR MEDICAL CONDITION.
If you get sick, make an effort not to spread viruses and bacteria among all expedition members. You should observe strict hygiene using sop and hand disinfectors regularly, especially when entering in mess tents and other communal areas, and when leaving the toilet.
If you take medicines, write down everything and changes in you condition.
Our mess tent in Khan Tengri basecamp, a festival for viruses and bacteria. Entry was prohibited without washing hands.
Acetazolamide (Diamox®) is a medication that forces the kidneys to excrete bicarbonate, this re-acidifies the blood, balancing the effects of the hyperventilation that occurs at altitude in an attempt to get oxygen. This re-acidification acts as a respiratory stimulant, particularly at night, reducing or eliminating the periodic breathing pattern common at altitude. Its net effect is to accelerate acclimatization, it makes a process that might normally take about 24-48 hours speed up to about 12-24 hours.
Common side effects include numbness, tingling, or vibrating sensations in hands, feet, and lips. Also, taste alterations, and ringing in the ears. These go away when the medicine is stopped. Since acetazolamide works by forcing a bicarbonate diuresis, you will urinate more on this medication. Uncommon side effects include nausea and headache. A few climbers have had extreme visual blurring after taking only one or two doses of acetazolamide.
It is highly advisable to consult with your doctor and test the medication if possible.
For treatment of AMS:The recommend a dosage is 250 mg every 12 hours. The medicine can be discontinued once symptoms resolve
For Periodic Breathing: 125 mg about an hour before bedtime. The medicine should be continued until you are below the altitude where symptoms became bothersome
If acetazolamide is stopped, symptoms will worsen: There is no rebound effect. If acetazolamide is stopped, acclimatization slows down to your own intrinsic rate. If AMS is still present, it will take somewhat longer to resolve; if not – well, you don’t need to accelerate acclimatization if you ARE acclimatized. You won’t become ill simply by stopping acetazolamide
Acetazolamide hides symptoms: Acetazolamide accelerates acclimatization. As acclimatization occurs, symptoms resolve, directly reflecting improving health. Acetazolamide does not cover up anything – if you are still sick, you will still have symptoms. If you feel well, you are well.
Acetazolamide will prevent AMS from worsening during ascent: Acetazolamide DOES NOT PROTECT AGAINST WORSENING AMS WITH CONTINUED ASCENT. Plenty of people have developed HAPE and HACE who believed this myth.
Acetazolamide will prevent AMS during rapid ascent: This is actually not a myth, but rather a misused partial truth. Acetazolamide does lessen the risk of AMS, that’s why we recommend it for people on forced ascents. This protection is not absolute, however, and it is foolish to believe that a rapid ascent on acetazolamide is without serious risk. Even on acetazolamide, it is still possible to ascend so rapidly that when illness strikes, it may be sudden, severe, and possibly fatal.
The mainstay of treatment of AMS is rest, fluids, and mild analgesics: paracetamol, aspirin, or ibuprofen. These medications will not cover up worsening symptoms. The natural progression for AMS is to get better, and often simply resting at the altitude at which you became ill is adequate treatment. Improvement usually occurs in one or two days, but may take as long as three or four days. Descent is also an option, and recovery will be quite rapid.
A frequent question is how to tell if a headache is due to altitude. Altitude headaches are usually nasty, persistent, and frequently there are other symptoms of AMS; they tend to be frontal (but may be anywhere), and may worsen with bending over. However, there are other causes of headaches, and you can try a simple diagnostic/therapeutic test. Dehydration is a common cause of headache at altitude. Drink one liter of fluid, and take some paracetamol or one of the other analgesics listed above. If the headache resolves quickly and totally (and you have no other symptoms of AMS) it is very unlikely to have been due to AMS.
We had to use it the last night in basecamp…
GPS location Date/Time:12/08/2012 14:38:29 GST
Having fun in the desert with my paraglider!
Disfrutando en el desierto con mi parapente!
Most of the people involved in regular sports do not realize about the difficulties that we mountaineers find along the way to the summit when it comes to having drinking water available at all times. During approach is normally easy to obtain water from rivers or springs, and in some civilized areas you’ll be able to get it in teahouses or similar places. Most of the time, these water sources are contaminated with various bacteria, viruses and protozoans. This becomes a real risk on areas where there is a prominence of farms and domestic animals, such us cows or yaks. Even in virgin mountain ranges like Jemtin Bel in Kyrgyzstan, where I was doing several unclimbed peaks this year, you might find the rotten body of a wild horse contaminating the pristine water sources. Microorganisms generally come from human and animal waste and are spread by rain and run-off.
Boiling is one of the oldest and most effective methods for sterilizing water, but it requires sufficient time and energy in the form of fuel. Boiling only eliminates micro-organisms. It will not cause the water to become clear, and chemical substances will remain inside. The various pathogens in water have different heat sensitivities, not all of them will be destroyed within the same time. At sea level the boiling point of water is 100°C. Boiling it for five minutes is adequate. At 4000 meters above sea level the boiling point drops to 86.8°C. At this altitude water must boil for 20 minutes. Therefore boiling water is normally not a completely safe option on high altitude expeditions. At Jemtin Bel basecamp I was provided with boiling water that was stored in barrels after treatment. These barrels were exposed to high temperatures and constant handling by expedition members that showed episodes of diarrhea. I felt like drinking water from the river was even safer than from these barrels…
Disinfectants destroy micro-organisms and thereby prevent the transmission of pathogens. The following substances and processes are allowed in the treatment of water: chlorine, chlorine gas, chlorine dioxide, iodine, ozone, silver and ultraviolet (UV) sanitizing. There are different products available in the market, but the one I found more effective and convenient is Micropur Forte disinfection tablets produced by Katadyn. These can be found in many places, but my favorite megastores are Decathlon and Globetrotter.
Decathlon is a major French-based sporting goods retailer operating hundreds of stores worldwide and serving 100 million customers every year. The start in France was with a shop in 1976. In the 90s, Decathlon expansion covered the rest of Europe and almost two years ago, in December 2010, the first Decathlon store in the Middle East was opened at the Mirdif City Centre in Dubai. Decathlon in Dubai is managed by the Azadea Group, a leading fashion and retail company present in the Middle East and North Africa, managing more than 45 international brands.
After few years using it, I find Micropur Forte the best water disinfection solution for the following reasons:
Silver ions combined with chlorine.Its technology is based on silver ions combined with chlorine, but it also contains Sodium dichloroisocyanurate wich is more expensive but more efficient than formerly used halazone water disinfectant. Mechanism of action is the release of chlorine in low concentrations by constant rate Chlorine disinfects water quickly and safely, and silver ions preserves water for up to 6 months.
Silver ion/chlorine dioxide based disinfecting agents will kill Cryptosporidum and Giardia, which neither chlorine nor iodine alone can be considered completely effective against. Boling will kill these microorganisms but with Micropur Forte there is no need to boil before treating.
It’s fast compared with other products and has a very long lasting effect. Eliminates bacteria and viruses in 30 minutes, amoebas and giardia in 120 minutes. Conserves drinking water for up to 6 months
It is very simple to use with high degree of user safety. Use one tablet for one litre of clear water, wait 10 minutes until the tablet has dissolved, shake well and wait another 20 minutes before using the water.
Small and handy packaging that fits everywhere. The tables are tiny and they come packed in two small blisters of 50 each, allowing for treatment of 100l
The light taste of chlorine is almost unnoticeable, and can be completely neutralized with Antichlorine produced by Katadyn other manufactures. I personally find it tasteless when using plastic bottles, metallic ones can become an issue after long periods of time due to the silver ions.
It is also ideal for conserving water free of micro-organisms in water tanks, water baths, air conditioning systems, heating systems, humidifiers, etc.
Micropur Forte has however some drawbacks:
The size of the tablets is so small that sometimes is impossible to handle them with globes. Many times I’ unsure I’ve actually dropped one tablet in the bottle or it got lost in between my fingers. Once in the water they are difficult to see. In most scenarios is quite handy to have very small size tablets, but when conditions harden, having big tablets will make things easier. I’d advise Katadyn to produce an alternative version in bigger sizes.
If the water is very cold the disinfectant effect slows down noticeably and then it’s important to wait up to two hours.
On non-clear water, suspended matter can weaken the effect of chlorine and silver ions. Therefore it’s advisable to use a microfilter like the one produced by Katadyn to treat cloudy water, which is the one commonly found around glaciers.
The cost of chlorine dioxide treatment is about four times higher than the cost of iodine treatment.
The use of metal container such us the classic aluminum bottles is not recommended since it can interact with the active components altering their properties. I used brand new aluminum bottles with Micropur Forte during my Island Peak expedition, and I noticed changes in the taste and smell of the water after couple of weeks. I used plastic bottles for my Khan Tengri expedition and I see difference, with none of these effects being noticed in four weeks or usage.
The maximum amount of silver in drinking water is 0.1mg/l. When this one is exceeded there is a risk of deposition and accumulation of silver compounds in various body tissues leading to a rare condition called argyria
Winter climb of Korma Kooh in Iran
At high elevations the water is normally found only on it solid forms. This for obvious reasons becomes a serious challenge when we need to drink big quantities but we don’t have liquid water sources for quick refill, disinfect and drink. Under these circumstances we have to be quite meticulous when calculating the amount of fuel plus treated water to take in our backpacks. Carrying an insufficient amount of water will lead to dehydration and all risks derived of it, as I explained in a previous post. Carrying a large amount of water will go to the detriment of food and fuel to be carried up the hill. Not enough fuel means little possibilities to prepare water and food, which by all means will have disastrous consequences. There are different factors that can be considered on our attempts to resolve the equation:
During my last few expeditions where we climb alpine style, we used gas cylinders and very light stoves. We also used heat deflective panels to improve the efficiency, by protecting the stove from the wind and concentrating the heat in the pan. In my recent speed ascent to Mt Damavand in Iran I used a Vango Ultralight Gas Stove with a large gas cylinder (propane and butane), and a mid-size aluminum kettle and pan. Since this was a fast ascent and we planned to spend the night in a shelter, we decided to save some grams with this system, but when camping outdoors it will be ideally complemented with the Vango Windshield, and bringing two or three small gas cylinders will make more sense. In my Khan Tengri Expedition we opted for the MSR WindPro II Stove with small gas cylinders (propane and butane) for improved cold-weather and low-fuel performance, combined with the Alpine 2 Pot Set that allows preparation of large amount of water for cooking and drink. The decision of using this system was made considering that in this climb we were looking at splitting food, gas and group gear in between teams of two. The Alpine Pot Set is ideal to prepare cooking water in the 1l pan, and once this one is boiled you can quickly switch to the 2l pan to melt snow to refill drinking bottles.
For the hardest conditions and lightest ascents there is a product that I have not had the opportunity to test yet, and it’s growing its popularity worldwide. I’m talking about the MSR Reactor, which features a radiant burner enclosed by a unique heat exchanger for the best performance in windy conditions. It has an advanced pressure regulator which provides optimal heat output over the life of a fuel canister. For maximum portability, the stove and fuel stow inside of a high-efficiency 1.7liter pot.
Both MSR and Vango products are distributed in UAE by Global Climbing, the main distributor of outdoor adventure brands in the Middle East. Global Climbing is also the regional representative of Walltopia climbing walls and HRT, two of the worlds largest and most innovative companies working with artificial climbing structures.
As for which gas to use, Butane or Propane, there are important differences to consider even though the physical properties of the two gases are similar. Butane is less toxic and contains around 12% more energy than Propane, and so you can squeeze more running time into the same sized bottle. It is heavier, but can be stored in light containers. There is only one disadvantage on the use of Butane against Propane, but for us mountaineers it a big one. The liquid in the bottle must be able to boil into a gas. In the case of Butane, this will happen at any temperature above -2°C, whereas with Propane, this figure is much lower, at -42°C. This means Butane will be useless most of the time, but propane requires heavy steel canisters to safely contain it due to the high vapor pressure at common ambient temperatures. A good compromise between burning efficiency at low temperatures and weight, is the use of blended fuel. The thinner canisters can handle up to about 30% propane, with the remainder being butane. The propane in blended fuels drives the system with its low boiling point, providing vapor pressure while the butane gas is carried along and burned with the propane. However at very low temperatures the propane burns off first, causing performance to drop for the last third of a canister. High altitude however offsets the effect of cold temperatures. The lower atmospheric pressure makes it easier for the liquid fuel to vaporize in the canister and supply the burner with gas.
In high altitude there are two things we can do to improve the efficiency of our canister stove system. Use blended fuel, and under freezing temperatures try to warm the canister to temperature over above °C. This can be achieved in many different ways, but always with extreme care to prevent disasters from happening, such us globes or tents going up in flames. Storing a gas cylinder in our sleeping bag will secure a good fuel performance in the morning. When we are about to finish a canister and before we switch to a new one, we can place it on top of the pan and some heat will transfer from the lid to the canister. Using some heat deflective and wind protection system, such as the Vango Windshield we already mentioned, will help heating up the canister during the process of burning. In case of emergency it is very useful to light up a small candle and use it to heat up the canister. In all cases we have to make sure the temperature of the canister doesn’t get too high. If it feels hot when touching, then we are crossing the limits…
One important point many people don’t take into consideration is that piezoelectric lighters do not work at all at moderate to high altitudes. Some gas stoves include one, but the spark won’t light up, making the system unusable. The voltage produced by the quartz crystal when deformed is too low with low air pressure, thus the spark is not lighted up. Always carry classic lighters, especially the ones producing lots of sparks, such as the old Zippo. Having waterproof matches as a backup is always a life saver.
Melting snow in the Alborz Range in Iran
One more thing that worth commenting in terms of efficiency when using water sources, is the type of food we bring up the mountain. I will write a separate article on this, since it a pretty extensive subject, but to for now I just want to mention few points. Food has to be tasty and energetic but we have to be cautious with certain aliments that require big amounts of water to be digested, such as those with high protein/fiber content. And of course avoid the consumption of foods and drinks that force the body to dehydrate, such as alcoholic drinks. If carrying extra weight is not a point of concern, it’s always a good idea to eat food that rehydrates you at the same time, allowing you to safe fuel on the process of preparing food and drinks. This is the case of almost all fruits and vegetables, but in high altitude expeditions it worth considering packed meals that are not freeze dried, but instead they only need to be heated for few minutes or can be eaten cold. During my recent Khan Tengri expedition, along with the popular Mountain House and extraordinarily delicious yet expensive FuiZion freeze dried food, we had Wayfayrer Meal Pouches ready to eat. I found them very convenient because you can eat them hot or cold as all contents are fully cooked. What you do is melting the snow, removing pouches from protective over-pack and putting a couple of them in the water to warm the food. Then you bring the water to boil, removing the pouches from the pan, and you can eat the food with its liquid contents while drinking the water you boiled in the process. In an emergency, when there is not water or fuel to prepare the classic freeze dried food, you can eat Wayfayrer Meals and that will rehydrate you and give you energy for few hours. These guys have also an alternative packaging for the Hot Food Kits, featuring a Heater System that is triggered when adding water. These are more expensive than the standard one we used, but surprisingly they weight the same, 300g per packet.
Wayfayrer Meal Pouches are also distributed in UAE by Global Climbing
Sorting out our food packs in the mess tent in Jentim Bel, Kirgizstan.
Coming back to our main subject, once the water is treated it has to be stored and transported. There are important points to consider here if we don’t want to end up with surprises when climbing high altitude. Water bottles and containers have to be selected according to different requirements. First the material must be strong and light and able to protect the water from the environment. Metallic bottles fulfill these entire requirements. They do not deform or brake with temperature changes or small impacts. This is extremely important as some other materials can become unusable very easily, which will force us to abandon our climb before finding a replacement. All parts in the bottle must be strong and preferably not detachable. Losing the bottle cap while handling with thick globes will make the bottle unusable. Classic aluminum and steel bottles are quite popular, but they have some problems. Fist the disinfectants, as we already discussed, can react with metal and the water properties will be altered or not sanitized properly. Also the bottlenecks are normally thin which make quite difficult and dangerous pouring boiling water from the pan, or adding purifying tablets or other additives. The caps tend to freeze easily, and those with flip straw become useless below 0°C. Plastic containers such us the Lifeventure Tritan® Flasks are more convenient. They are strong, with wide mouth and attached loop-top that never gets lost, screws on and off easily and rarely freeze. They are made of BPA free translucent copolyester, which is almost impossible to break, odourless and tasteless, allows you to see the contents, and do not interfere with the chemical sanitizers. They are also my favorite pick as pee bottle. For long and demanding expeditions I carry two 1l flasks in my backpack along with a small 500ml Lifeventure Tritan® Bottle. This one I keep it warm and accessible in my down jacket, and I refill it with the contents of the big flasks. It’s easier to drink small zips constantly if the liquid is accessible and not too cold to scare your taste buds. Drinking small zips constantly will keep you hydrated as I discussed in a previous post. The only problem I see with these water containers is that the contents tend to freeze easily, including the one in the pee bottle… A frozen pee bottle cannot be emptied, and believe me, in a very long and cold night in your expedition tent that is not fun at all! There are thermal covers that can be used with these flasks and bottles, such us the Lifeventure Thermal Mug Jacket that fits the Tritan Bottle. For the pee bottle, a good advice is to use one of these covers for your 1l flask, and after you take the first leak, unseal one chemical foot warmer, stick it to the bottle inside the cover to keep the liquid nice and warm till the morning. Leave some room inside the sleeping bag for water bottles and all gadgets, and use my trick to leave the potty outside.
Lifeventure brand is within the list of products distributed in UAE by Global Climbing
For my Jentim Bel Unclimbed Peaks and Khan Tengri expeditions this year I used a totally new product that is designed by Zefal to keep your drink at an optimal temperature for over 2 hours and a half. And it really worked well! The Zefal Arctica bottle is strong and flexible, with wide opening that hardly freezes, and the insulation is optimal. It’s BPA free, odourless and tasteless, with a capacity of 700ml. Once you fill the bottle with hot liquid, you can leave it outside your sleeping bag, and after ten hours sleeping you’ll find the contents ready to drink. Close to the mouth where the insulation is minimal, you can find some ice, but that can be avoided by adding extra insulation to that part with a cover you can make yourself with neoprene. The inner tank is removable, and between this one and the outer tank there is the same material used in the insulation bags you can buy in the supermarket to transport frozen food. Removing these parts however is not advisable in my opinion, since they are partially sealed at the mouth, and I suspect we can alter the thermal properties of the system. There is something to take care with when using these bottles. The plastic is strong and flexible, but when you pour boiling water in, the inner tank deforms due to the difference of temperature with the outer. The volume then tends to shrink, meaning that we reduce it from 700ml to something around 500ml as per my calculations. When this happens you can always unseal and remove the inner tank and bring it back to its original form using your hands and some heat.
Zefal products are distributed in UAE by Sport In Life, distributors of Polar Heart Rate Monitors, 2XU Performance Gear, Nathan Sports, GU Energy and Aqualyte. They have a nice online shop SportSouq.ae and Facebook page to keep us updated with events such as the recent Warehouse Sale or Wadi Adventure competition.
Scrambling in the last section of our Unclimbed Peak #1 in Jentim Bel, Kirgizstan. Carrying enough water in two Zefal Arctica bottles.
All products distributed by Global Climbing and Sports in Life can be found in many places in Dubai, but the one shop stop for outdoor enthusiast is Adventure HQ. Located at Dubai’s Times Square Centre, it is the ultimate destination for outdoor adventure gear. They also have an Adventure Zone featuring the Cable Climb and Climbing Pinnacle, as well as a The Chill Chamber where you can experience -25C temperatures. I was lucky to have Adventure HQ allowing me to use such facility to test my brand new equipment for few days before departing to my Khan Tengri Expedition, and I look forward to get help from them again as I prepare for my next extreme challenge. I totally recommend all adventure junkies in UAE to visit the store and sign up for the free Adventure Club membership. This give us access to special member only offers and keep us up to date with cool events, promotions and other benefits. From time to time we get things like 100DHs vouchers!
Testing some of my gear in the Chill Chamber, in Adventure HQ
GPS location Date/Time:12/02/2012 06:55:25 GST