On 2o July I could not stop myself from thinking about Jeff Bezos. He made a short journey to space, organizing his own private trip. There were plenty of headlines. And many different opinions on the subject.
Was the issue that was of concern to me if he was returned from space safe and sound?. Well, not exactly.
My concern was not in how much the space trip cost (or maybe yes), not in thinking if his decision had a coherent basis (or maybe yes) or in the high-impact maedia coverage (or maybe yes). The problem was that I couldn´ t get out of my mind the environmental impact of the trip, from a life cycle perspective.
After the trip, Jeff Bezos said its spaceflight revealed the fragility of Earth.
But was his trip a sustainable initiative for this fragiel Earth?
Jeff Bezos spaceflight. Source: France 24
Sustainable development is a development that meets the needs of the present without compromising the ability of future generations to meet their own needs, shifting its focus towards the economic, social and environmental development.
To be able to say that the environmental part of the sustainability is being considered, it is needed to evaluate the impact and communicate the result through effective and transparent communication indicators, such as the carbon footprint. It estimates the total amount of greenhouse gases emitted during the production, processing and retailing of goods and/or services, considering their life cycle and using the global warming potential as the only indicator.
It seems that we are becoming aware of the importance of improving energy efficiency at home or using the pblic transport, but we continue to maintain many unsustainable practices in our day to day. For instance. I would ask you to think about the energy consumption required by your daily interactions on the internet. Then, multiply this number by 4,200 billion Internet users.
“Houston, we have a problem!”
Knowing which activities are the largest sources of GHG in our everyday lifes, we can change them towards more environmentally friendly actions, and thanks to the information shared by the International Energy Agency (IEA), I would like to tell you three steps to take a digital detox that will minimize your carbon footprint.
Cleaning: delete emails and online files that you no longer need. This action frees up space on the servers. And the social media accounts that you no longer use. The simple fact of existing and occupying space on the internet generates an environmental impact.
Unsubscribe from the newsletters you are not reading: whilst the carbon footprint of an email is not huge, cutting down on the number of unnecesary emails you receive is one important way to reduce the CO2 eq emitted by these emails. And in a matter of emissions, each email counts.
Choose carefully what videos you would like to play, maybe a pocast would be better.
Applying the equity principle to the environment, each person in the world has the right to us the same amount of environmental space, so if we commit ourselves to use efficiently our resources with minimal environmental impacts, the whole society will benefit.
Touché.
Because this implies that the responsability is shared by everyone. That is to say, it is not only from Jeff Bezos.
The technological offer at CARTIF is varied, we are not dedicated to space tourism but we do evaluate the sustainability and calculate environmental footprints.
Therefore waiting for Jeff Bezos call impatiently!!
It is said that those who forget their own history are condemned to repeat it. Cultural Heritage is part of that history, talks about our beliefs and experiences, it carries us where we came from and grants our identity. Knowing it helps us to understand the problems of the present and preserving it is essential to ensure the new generations can continue learning from it.
Historical building is the wider and most significant cultural heritage set transferredup-to-date, bringing together immovable assets (the buildings themselves) and movable assets (what these contain) of great interest. Therefore, if we want to conserve our heritage we must keep historical building in the finest possible condition. This way we will guarantee its physical integrity and ensure that it can continue to be used by residents and visitors.
Since 2012, conventional buildings in Spain have undergone a periodic inspection known as ITE (Technical Building Inspection), similar to the Vehicle Inspection Test but applied to buildings. This inspection evaluates the adequacy of the assets to the required conditions of safety, healthiness, adornment, habitability, accessibility, use and services, and it applies to buildings older than 50 years with preferably residential use.
So, if buildings from 50 years ago are being inspected, shouldn´ t those built 500 years ago also to be inspected?
The reality is that, as it is raised right now, the conventional inspection is not applicable to historical assets. First, because of the regulation framework, which makes it mandatory in municipalities with a population higher than 25,000 inhabitants, a case that does not represent the built heritage, mostly found in rural areas with a significantly lower population. Secondly, beacause heritage buildings are very rarely used for residential purposes (even in urban areas), and, if so, it tends to occur in fully rehabilitated or newly-built annexed areas, adapted to the uses and customs of the 21 st century. But, above all, the application of the conventional inspection to historical buildings is not feasible because it is obvious that conventional and historical buildings present great construction, materials and use differences, consequently, it must be a specific inspection to verify how they are, just fitting the uniqueness and sensitivity that cultural heritage demands.
This is the origin of the ITEHIS project, which studies the applicability of innovative technologies to the technical inspection of historic buildings older than 100 years, provided with a specific use and subject to be classifiable into one of the major architectural groups: civil, military, religious or industrial. In other words, ITEHIS aims to adapt the already existing buildings inspection to the exceptional features and endless architectural, constructive, functional and aesthetic variations that can be found in historical buildings, also considering the movable assets they contain (organs, altarpieces, stalls, collections,etc.). This is also tight to the broad context od the digitization of Heritage, bringing together all the aspects inspected through HBIM (Heritage-BIM), which we already talked about in a specific post called “The BIM approach: fitting to Heritage?”. Once the inspection is concluded, a report will be delivered, providing improvement measures rating the historical building from 1 to 5. This will allow not only to evaluate its condition, but also to objectively prioritize the resources needed to its conservation. Furthermore, ITEHIS will help to lay the foundations of a specific regulation to guarantee the sustainability of historical buildings through the Spanish Standardization Committee.
ITEHIS, project financed with FEDER funds through the Instituto de Competitividad Empresarial (ICE), is another example of collaboration between a technology centre such as CARTIF and companies committed to Heritage snd the territory they are settled (TRYCSA, ALTEISA and ACITORES), which intend to contribute to those proper conservation through new, more effective ways, so that we can continue knowing, using, enjoying and, ultimately, learning from it.
A lot of the new hype arounf the Artificial Intelligence (AI) is directly related with the potentiality for imitate or overcome the capabilities of the human brain (in terms of data volume managed and process speed) using computers. The neuroscientist Henry Markram in 2009 announced a project that pretend to simulate the human brain in a super-computer with different objectives such as “understanding perception or reality and maybe even undertanding physic reality as well”.
The so-called “technological singularity” established how the AI and robotics will surpass us humans. There are different predictions about when will occur this “apocalypse”. Elon Musk figured it out this singularity in 2025, the Russian millionaire Dmitri Itskov in 2045, to cite some examples. The continuous advance of microprocessors capabilities also feeds, wrongly, the hype of the AI. If someone compares only the numebr of neurons (around 86,000 million) with the number of transistors of the last M1 chip from Apple (16,000 millions) may be tempted to ensure that the “computation capacity” of the human being is easily overcome. I know, comparisons are hateful, and in this case, very daring.
Until very recently I was already among the expectant of such predictions, but with a reasonable scepticism degree. All this changed for me in the crudest of the confinement of 2020. I was wandering around YouTube in search of interesting videos related to AI and I came to a very curious one that gives the title to this post, and that attracted my curosity: 1consciousness is not a computation. In this video, a more than kucid Sir Roger Penrose, physicist, mathematician and philosopher, is interviewed by the vlogger Lex Fridman, expert in AI and autonomous driving.
I have to say that, even the scientific level of what is exposed in the video is very high, the lucidity, detail and kindness shown by Penrose, caught me and got me to be attentive throughout the whole interview. Specially, there is a part that sticks me on the chair, and makes me rewind several times to try to understand as much details as possible. The interview starts directly with this devastating thesis: “I´ m trying to say that whatever consciousness is, it´ s not a computation…it´ s not a physical process which can be described by computation”.
During the interview, Penrose explains how his curiosity about neurophysiology led him to explore the basic principles of the physic, cosmology, mathematics and philosophy in his book in 1989 “The Emperor´ s New Mind” to propose that human thinks could never be emulated by a machine, against the “mainstream” thesis of those times about how computers using artificial intelligence could soon make everything a human can do.
Which leads him to assure so bluntly the impossibility of emulating human consciousness by using a computer? It is not supposed that joining several chips of our computers one could overcome the number of neurons of our brain and its capacity of computation (if you allow me this crude comparison)? Just like life isn´ t a set of cells grouoed in organs, the “emulation” of the brain capacities is not a question of grouping a high number of transistors and their electrical impulses. We all remember the explanations of how neurons transport information throughout electrical impulses. In his analysis of the brain physiology, Penrose, even at the final of his book could not get to explain completely how it was possible that the nervous signals could transmit by electrical impulses consistently across the brain. Something did not fit or was missing in his theory. But it seems that, to a reader of his book, the anaesthesiologist Stuart Hameroff, was to the only one that figured it out. “I think you have missed something, don´ t you know what microtubules are?”- said to Penrose. “Is what you need to amke your theory work”. Microtubules could be the answer to the Penrose search about a no computable source in the human consciousness, from a physiological point of view.
But what the hell are microtubules? May molecular biologists forgives me, but it seems that they are molecular structures of tubular shape that we can found in different cells of our body, from red blood cells to neurons. These structures that “inhbait” the interconnections of our grey cells, have the property of conserving their state in a very effective way (quantum type state, but we will leave this for another post) and allow us to somehow return to being the same as we were after a loss of consciousness, for example, after and anaesthesia. We could say that microtubules are the basic storage unit (quantum) of our brain. Some scientifics call them “the neuron brain“.
Another reason for being able to aspire to emulate the brain has been to be able to replicate the number of connections that exist in our neurons. It´´ s a pretty big number actually. It is estimated that each neuron has an average of 1,000 connections. With 86,000 million of neurons this would give us about 86 trillion of connections or so. Even though the numbers give vertigo, for some experts they seems achievable with the current calculation capacity in operations per second (FLOP) of the processors. Going back to Apple´ s M1, this processor declares to be able to carry out 2.6 TFLOP, 2.6 billion operations per second (10 to the 12th). Again, a number apparently “near” to our connections if we join a lot of chips working at the same time. With the dazzling emergence of chatGPT, the debate continues. Its capabilities seem human-alike and its more than 175 billion parameters generate an illusion of understanding. But it seems that consciousness is something more than connections or parameters of a mathematical model, right?
If we focus only on the quantitative question and we return to microtubules that inhbait our neurons, how much of them can we have? Neurobiology said that inhabit our neurones, how much of them can we have? Neurobiology said that more than 1,000 microtubulesper each one of our 86,000 million of neurons, that is, 86,000,000,000,000 micortubules (86 billion, similar to the neural connections) that “stores quantum information” in which some scientifics affirm, our consciousness live. We can say that actually our brain is a quantum computer, don´ t you think? Wow, sorry to fall back into a computational analogy. Let´´ s go back to the technology to conclude this post. IBM, promises a quantum computer of 1,000 qubits for 2023. Quite inferior to the 86 billion microtubules of our head. In my humble opinion, and comparing only quantitative aspects of actual and future computation capacities, the so called “technological singularity” as a promise of overcoming our human capacities only with actual computer technology and artificial intelligence i still very far away or seems almost unattainable. I don´ t know about you, but I still see a little bit far away the technological singularity, don´ t you think?
1 Human beings’ ability to recognize and relate to the surrounding reality
When we hear energy efficiency, we always think in improving productive process in facories where we work, in the means of transport we use to move… but never in daily chores in our home. Actions as common as choosing an appliance or the cooking way, establish the degree of our awareness with energy efficiency at homes.
Reflecting on this aspect, these common activities are associated with energy consumption, and therefore, any action aimed at making them more efficient will affect the consumption of our houses. In addition, this concept takes on special relevance in the current context of a growing escalation in the prices of the energy we consume, which is proposed to last over time.
Some measures imply an economic investment, which in many cases presupposes a negative attitude, although we need a reflection on them or a good awareness campaign about it. For example, there are few homes with an incandescent bulb, and the use of bulbs with LED technology is already very common. In the same way, progress in being made in the introduction of more efficient electrical appliance in our homes. These are classified with a letter (A,A+ …) which indicates the consumption of the equipment. Although those that consumes less tend to have higher cost, it must be considered that over time this investment is compensated with a lower cost of electricity.
But not all these soluions that improve our energy efficiency necesssarily imply an economic cost. Thus, for example, we can save energy by acting on:
The control of the heating and cooling temperature setpoints, maintaining adequate comfort values, and although, currently, we are more aware, surely, we all know homes where tenants usually find themselves in winter with summer clothes because they prefer to select a higher temperature setpoint than necessary.
The way we air out our homes. It is not necessary to do it for a long period of time, as is very common to see, and to carry it out at the appropriate times of the day (example: in winter, when the outside temperature is higher or in summer, in the early hours). This measure, complemented by a proper use of the blinds,opening them in sunny hours in winter and closing them in those periods in summer, allows a considerable reduction in air conditioning consumption to be achieved. It is true that with the current pandemic situation and the COVID19 measures to increase the ventilation of closed places, it is difficult to apply efficiency.
When cooking, trying to take advantage of residual heat from glass-ceramic hobs by “turning of the fire” a few minutes before finishing cooking or planning our menus and taking advantages of the ignition of ovens to bake several dishes.
Turning off lights in areas where you do not stay, or disconnecting standby equipment that is not going to be used for a long periods of time or at night.
Wash properly, using the economic programs of both washing machines and dishwashers, and preferably do it at full load, which not only saves energy but also water, a good in many cases scarce.
These and other small measures are a good starting point to save energy in our homes. We have to think that not being efficient does not only mean a higher energy expenditure or an increase in our electricity and gas bill, but it also means a damage to our society and the environment that surrounds us.
At CARTIF, we investigate in many areas of energy efficiency in buildings, developing multiple projects in this field, and we consider that the energy awareness and training of the end users of buildings, even in measures as simple as those indicated, is an important aspect and it has repercussions in progress and social benefit for all.
It is a reality that the building stock, not only in Spain, but in Europe in general is outdated. Although this can be a positive indication that cities have years and history, and buildings can be heritage with high historical value, the reality is also that a large part of them are not energy efficient. Approximately 85% of European buildings were built before 2001 (according to the Renovation Wave Strategy document)
The specific regulation on thermal insulation of the building envelope appear for the first time around the 70sm which means that buildings over 50 years old (more than 40%) were built without any requirement on energy performance. In general, buildings are responsible for 40% of total energy consumption in the EU, and for 36% of greenhouse gas emissions. It must be taken into account that the current regulations for new construction are strict enough in terms of energy efficiency and emissions (through theEnergy Performance of Buildings Directive, the EPBD): since 2019 it is mandatory that all new public buildings be nearly Zero-Energy Buildings (nZEB), and, since the end of last year (2020), it is mandatory for all new buildings. Therefore, the focus is now on meeting better energy efficiency standards in the rest of the building stock.
The COVID-19 crisis that we are experiencing has also put the focus on the buildings, which have become an office for teleworking, a nursery or classroom for children and students, even the main place for entertainment and (online) shopping. Europe sees this as an opportunity to join forces and, while addressing the way to overcome the COVID-19 crisis, also take advantage of the effort that has been made for years in retrofit, to rethink, redesign and modernize the building stock, adapting it to a greener environment and supporting economic recovery.
The European Commission already set in 2018 the long-term objective of being climate neutral in 2050, and last 2020 it established a medium-term objective of reducing greenhouse gas emissions by 2030 by 55% compared to 1990 level. To achieve this objective, buildings must make a great contribution, since they are responsible for a high percentage of these emissions, with approximately a 60% reduction; in addition to a 14% reduction in final energy consumption and 18% in energy consumption for heating and cooling. These are the premises of the Renovation Wave Strategy to improve the energy efficiency of buildings, with the aim of at least double the renovation rates over the next 10 years, thus promoting energy renovation in buildings throughout the European Union.
Furthermore, to support this, Europe is trying to ensure accessible and well-oriented financing, through initiatives within the framework of Next Generation EU the post-pandemic recovery plan, aimed at rebuilding post-COVID-19, which will also have a part for energy refurbishment in buildings.
In view of all this transformation that will take place in Europe, the European Commission has also begun to worry about aesthetics (because, as we said at the beginning, it is about transforming the old building stock, but paying attention to its historical value and as heritage). This is where the new European Bauhauswas recently born, a policy lab to work with citizens, as a participatory initiative to create resilient and inclusive cities, co-designing and co-creating a new style to provide more harmonised and sustainable future; materialising the European Green Deal and accompanying it with an aesthetic that characterises the sustainable transformation.
Is it true that these existing initiatives in the European context help and facilitate the definition of strategies for renovation of the building sector, but, if we were the politician responsible for improving the building stock in our region or municipality, where would we start?
First, it would be necessary to generate the most detailed knowledge possible of the building stock. Well, in this way, the policies on renovation and energy retrofitting in buildings will be more precise and specific to the real problems, and the solutions and financing offered adjusted to the status of the building stock in each case.
For this, we can make use of the public databases of existing buildings. At European level, the Building Stock Observatory (BSO) stands out among others, where information is collected digitally on the status of European buildings, providing a better understanding of the energy performance of buildings through reliable, consistent and comparable data. A relevant data source at European level is also TABULA/EPISCOPE, two European projects, one as the follow-up of the previous one, which provide a database of residential buildings based on defined typologies according to the size, age or other parameters, providing a set of examples for each of the countries analysed representing these building types.
Another important source of information for the characterisation of the building sector is the Energy Performance Certificates (EPCs) (more detailed information on this in a previous entry) of buildings, by analysing the documentation provided in the general registry of each region (autonomous community) or at national level, depending on the country. This certificate, beyond obtaining a label on the building’s energy consumption and its CO2 emissions (with letters from “A” to “F”), contains specific data on the year of construction, the construction characteristics of the building’s thermal envelope, energy systems, proposed measures to improve the energy rating, etc. So it becomes valuable information to know the status of buildings and the actions that could be carried out to improve that status, and to be able to extrapolate it to neighbourhoods, cities, regions and countries.
At CARTIF we participate in different projects aimed at improving knowledge of the building sector, and to support in decision-making that help in the definition of future renovation strategies. For example, in BuiltHub a data collection of the European building stock is carried out, as well as a roadmap is established on how to obtain reliable and useful data for the development of renovation strategies. Other projects, such as ELISE Energy Pilot, MATRYCSand BD4NRG, use the data from the Energy Performance Certificates (EPCs) to get a better knowledge of the status of the building stock in different regions (autonomous communities in the case of Spain), while it also participating in the development of a common certification model for Europe. Or the TEC4ENERPLAN project, where advanced techniques for multi-scale energy planning (from building to region) are developed, and support for the development of tools that serve as the basis for meeting the 2020-2050 energy efficiency goals.
The word “Digitization” is ubiquitous today. The term is extremely used but its meaning is worn out when taken to a specific terrain. Answering to how?, with what?, for what?, and even, why? for the particular case of Cultural Heritage it is not an easy taks, nor closed. Digitization and Heritage is a Romeo and Juliet style romance (to make a cultural simile), where the respective families view the matter with suspicion, even when it is destined to be a well-matched marriage, not one of convenience.
Digitization sounds technological, state-of-the-art. Heritage sounds archaic, old-fashioned. Putting one together with the other, and avoiding formal definitions (otherwise non-existent), it is proposed to define digitization in this case as the incorporation of digital technologies (those based on electronics, optics, computing and telecommunications) to the products, processes and services that organizations follow and offer for research, protection, conservation, restoration and dissemination of Cultural Heritage.
Digitization affects the way of facing work, the proper way of working and the organization in itself, modifying its structure and managing. This alteration in the organization schema causes an atavistic fear of losing the artisan and professional-knowledge supported value that features the companies in the Cultural Heritage sector, made up of more than 90% by SMEs in the EU. This is the real reason why they take the longest to “digitize”. It is not just an issue about buying, installing and operating computers, software and wireless networks. The change is deeper: it is not a question of appearance; it is a fundamental question. But it is well worth remembering that the workshops and people who appear in history and arts books today because the works they have bequeathed, are indeed famous for having innovated and used the best technologies available on their time.
But, what are the technologies at stake today for the Digitization of Cultural Heritage? Without being exhaustive, and also being aware of leaving things in the pipeline, the most demanded technologies are summarized below:
Multidimensional modelling and simulation (including Heritage BIM -HBIM[1]-): exact 3D virtual replicas of movable and immovable assets; mechanical, electrical, acoustic, lighting and signal coverage simulations with specialized software; 4D (evolution in time). The HBIM parametric modelling is remarkable to complying with Directive 2014/24/ EU and also to addressing extra dimensions: 5D (costs); 6D (sustainability and energy efficiency); 7D (maintenance).
Sensors, Internet of Things (IoT) and 5G: multipurpose devices for capturing, combining and communicating all kinds of data over the Internet. The 5G allows making between 10 and 20 times faster the traffic of these data compared to current 4G mobile communications. These technologies are typically used in structural and environmental monitoring for condition assessment.
Data analytics to get useful information: cloud computing (to archive all kind of information and making it accessible and searchable from anywhere and from any device connected to the Internet); edge computing (local computing -on the axis-, to improve response times and save bandwidth); big data (massive treatment of structured and unstructured data – in the order of Petabytes: 1015 bytes-). The determination of causes and effects, together with the prediction and characterization of behaviours (including visitor flows) are common examples
Artificial intelligence (AI): machine learning (ability to learn without specific coding) and deep learning (learning based on neural networks that mimic the basic functioning of the human brain) are well-known. One example is the Gigapixel technology to enlarge images to see tiny details thanks to intelligent computer processing of extremely high-quality photographs. Another example is the automatic recognition of symbols or animal species in a prehistoric rock engraving on which a-priori nothing can be distinguished.
Systems dynamics and informational entropy: they are ways of studying adaptive mechanisms in complex and changing systems (such as all those that humans forge -which are precisely characterized by creativity and culture-) to make predictive models or to support decision-making and management.
Computer vision: capturing and processing of images by cameras that operate in one or more spectral ranges to see beyond our eyes also at all scales (from space with COPERNICO satellites, to the microscopic world): search for patterns, detection of pests , humidity, alterations, irregularities and falsifications, definition of authorship and artistic techniques, conservation assessment. Applied to video analytics, it is very effective in guaranteeing the security against theft, vandalism or looting.
Digital twins: combining some (or all) of the previous aspects (multidimensional modelling, simulation, computer vision, sensors, IoT and AI) upon a virtual replica ready to remotely work under a multidisciplinary approach, allows to anticipate possible problems and experiment safely before performing any intervention, helping to its optimal planning. It can be applied to movable assets, but it has special significance in immovable ones.
High-quality audio and video: Hi-Res for audio and FullHD, 2K and 4K for video are words already entered in our lives. They allude to the highest attributes and durability of the audio and video formats that can be used for the registration of intangible heritage or the broad dissemination of heritage in general.
Virtual reality (VR), augmented reality (AR) and mixed reality (XR): to recreate spaces, decorations and configurations, past or future, even to look into planned interventions upon 3D models using special glasses or smartphones.
Ontologies and semantics: to uniquely name and hierarchically structure the constituent elements of movable or immovable assets and cultural landscapes so that they are understandable both by specialists and laymen regardless of their language and cultural background.
Interoperability: to synchronize data, systems and processes nevertheless of their origin and format.
Cybersecurity: to defend against malicious attacks on computers, servers, mobile devices, electronic systems, networks and data. Blockchain allows avoiding falsifications as well as guaranteeing the authorship and the digital visa of projects.
Robotization and 3D printing: configurable robots (adaptable, shippable and remotely-assisted) allow the modular construction of specific elements in-situ. They also allow the automation of inspection, cleaning, assembly, conservation and restoration processes in dangerous or hard-to-reach places, quickly and accurately. It can be combined with 3D printing for sealing, insulating and watermarking in different materials and finishes. Particularly 3D printing allots functional replication (total or partial) at different scales to create prototypes, parts, mock-ups and test series.
Nanotechnology and new advanced materials: the continuously increasing processing power of computers and their combination with the hardware of machinery allows the study and manipulation of matter in incredibly small sizes (typically between 1nm and 100nm), resulting in a wide range of materials and techniques usable in conservation and restoration.
In March 2021, the European Commission published a report that reviews and evaluates the actions and progress achieved in the EU in the implementation of the Recommendation (2011/711/EU) on digitization, online accessibility and digital preservation of cultural heritage as one of the main political instruments in those matters[1]. The ecological and digital transitions are, in fact, the keys to the agreement on the so-called Recovery Plan for Europe[2]. EU Member States have agreed on the need to invest more in improving connectivity and related technologies to strengthen the digital transition and emerge stronger from the COVID-19 pandemic, transforming the economy and creating opportunities and jobs for that Europe into which citizens want to live. During the confinement society has shown that Cultural Heritage in digital format was a true social balm, with museums and collections open online 24 hours a day.
Thus it is the right time and there are no general solutions for “digitization”. Cultural Heritage is not about producing thousands of cars, parts or packaging per day. Quite the contrary: each company, each project, each asset must be considered for what it is: something unique. To make a clear example, imagine somebody getting into the supermarket and asking ‘what is there to eat?’ The answer, consonant with the perplexity, could be: there are from precooked to fresh, meat, fish, eggs, dairy and sweets in all possible varieties. It depends on your culinary tastes, your hunger and the time you have, your nutritional needs, the time of day … In short: particular problems require particular solutions.
