On the optimality of individual entangling-probe attacks against BB84 quantum key distribution

It is shown that an existing method to study ideal individual attacks on the BB84 QKD protocol using error discard can be adapted to reconciliation with error correction, and that an optimal attack can be explicitly found. Moreover, this attack fills Luetkenhaus bound, independently of whether error positions are leaked to Eve, proving that it is tight. In addition, we clarify why the existence of such optimal attacks is not in contradiction with the established ``old-style'' theory of BB84 individual attacks, as incorrectly suggested recently in a news feature.Comment: 12 pages, 3 figure

Biocompatibility of materials and products used in medicine and dental medicine

BackgroundBiomaterials are defined as substances intended to replace a part of the body or its function in a secure, safe and economical way, while being physiologically and aesthetically acceptable. Biomaterials can be bioinert or regenerative. Biocompatibility refers to the ability of a material to elicit a specific biological response after administration in a living organism. Measuring the biocompatibility of materials used in dentistry is not an easily achievable task.MethodsScientific databases – PubMed, Scopus and Medline, as well as monographs, textbooks on the topic, websites were used to search for the data required. The following keywords were used: biomaterials, biocompatibility, dental medicine, medicine, toxicity.The aim of the following article is to summarize the main conclusions authors in the field have reached to when discussing biocompatibility and tolerance of material and products used in medicine and dental medicine.Results and discussionIn depth results and discussion are presented in the section. Materials used in medicine and dental medicine encompass a wide range of compounds, with different chemical and physical structures. Therefore, profound knowledge is needed to be able to treat the patients and keep them safe as much as possible from possible adverse biological reactions.ConclusionsMedical and dental specialists should pay special attention to the content of the materials they implement in their treatment plans on a daily basis. Being profoundly informed on the general diseases, medications usage and allergic status of their patients can prevent adverse complications. Although medicine explores and studies in depth possible biological reactions, still they may occur

Vestibular effects of diving

Over the last 45 years, recreational self-contained underwater breathing apparatus (SCUBA) diving as a leisure activity has increased in popularity. According to the Professional Association of Diving Instructors (PADI), more than 23 million diver certificates have been issued across the globe. Given the popularity of scuba diving, it is incumbent on every physician to know and understand the specific medical hazards and conditions associated with scuba diving. Although diving has become more accessible and the equipment is much safer now, diving still has its inherent dangers. Each year incidents occur, ranging from seasickness and sinus problems to heart conditions and mortality. More than 80% of all diving complications occur in the head and neck region. A number of studies have found that diving can lead to the development of vestibular disorders such as: Barotrauma, Decompression sickness, Otitis externa, Bilateral exostoses, Chronic sinusitis (barosinusitis), Serous tubotympanic catarrh, Tinnitus, Dizziness, Vertigo.The aim of this paper was to share our experience in the field of treating patients with different types of ENT disorders after or before a diving session. We briefly summarized the most important information for some of the disorders.We included in our study for a period of 12 years: a total of 24 patients (four females and 20 males), who dive. They were between 25 and 55 years of age. Some presented in clinics with an ENT disorder. 19 were professional, qualified divers, five (three males and two females) dove for the first time. On all 24 patients we performed: audiometry tests, Tympanometry tests, OAE, Static and dynamic vestibular tests, vHIT – in the last five years, otoscopy examination, dental check-ups.All divers – no matter professionalists or not – should follow these recommendations: a thorough prophylactic ENT check-up should be performed before an active diving session. Chronic ENT inflammations should be addressed in a timely manner. Divers should follow all instructions from the certified Diving Associations

Artificial intelligence – the new suggestion for biomedicine, dentistry and healthcare

The development of technologies based on Artificial Intelligence (AI) and their application in medicine is growing rapidly. Innovations in digital technology, telemedicine, 5G technology and artificial intelligence (AI) create new opportunities for the development of the healthcare system. The aim of the present study is to explore the possibilities for the application of artificial intelligence in biomedicine, dentistry, healthcare and healthcare. In recent years there have been many major innovations, including the introduction of many new information and communication technologies. Digital innovations, including the further inclusion of telemedicine, the development of 5th generation wireless networks (5G) and artificial intelligence (AI) approaches, create an exceptional ecosystem for new health opportunities. The digital health sector creates a favorable environment for the provision of health services at a very high level

History of the World Sleep Day

BackgroundSleep has also been cherished by society as a basic human need with a crucial importance for human health. People spend around one third of their lives sleeping. Nowadays, it has never been harder to achieve a restful sleep. When sleep is better understand, that will lessen the drawbacks of the different sleep disorders. Healthy sleep is important for maintaining physical and mental health in adult individuals. Sleep deprivation poses a significant risk for the individual and leads to psychological conditions, such as depression and anxiety. Several sleep disorders are known to the science. If breathing during sleep is not regular, a case of obstructive sleep apnea (OSA) may have been diagnosed.The World Sleep Day is traditionally celebrated in March, on the Friday before the Spring vernal equinox of each year. It is a global awareness and internationally recognized event, organized annually since 2008 by the World Sleep Day Committee of the World Sleep Society. Organizers aim to raise awareness of the problems with proper sleep, sleep disorders and aspects connected to it – medical, social, educational and others.MethodsScientific databases – PubMed, SCOPUS and MEDLINE were used to search for the information targeted. The following keywords – World Sleep Day, history, events, prophylaxis, sleep disorders were used. Information from the official websites of the societies involved in celebrating World Sleep Day was included as well.The aim of the following article is to study the history of the event from its foundation till today, aiming to stress out its usefulness.Results and discussionWorld Sleep Days has been internationally celebrated since 2008 for 15 years now. Since 2016, Bulgaria actively participates in all events organized by the World Sleep Society – Scientific symposiums, prophylactic check-ups for obstructive sleep apnea, elective disciplines in the teaching of students are organized. Importance is put on informing society about the dangers of undiagnosed and untreated sleep disorders, especially sleep apnea. Sleep medicine and Dental Sleep medicine are not recognized as medical specialties in the Republic of Bulgaria.ConclusionsProblems of sleep are extremely common in our days. The situation is continuously being worsened due to the hyperconnectivity people experience with the glowing computer and mobile phone screens. It is admirable that specialists in the field and society try to raise awareness and combat the poor sleep quality consequences. Only by doing the abovementioned, alleviation of the undesirable outcomes of irregular sleep can be reached. Legislative measures should be taken in order to certify Sleep medicine and Dental sleep medicine as medical specialties in theRepublic of Bulgaria

A Novel approach to quality-of-service provisioning in trusted relay quantum key distribution networks

In recent years, noticeable progress has been made in the development of quantum equipment, reflected through the number of successful demonstrations of Quantum Key Distribution (QKD) technology. Although they showcase the great achievements of QKD, many practical difficulties still need to be resolved. Inspired by the significant similarity between mobile ad-hoc networks and QKD technology, we propose a novel quality of service (QoS) model including new metrics for determining the states of public and quantum channels as well as a comprehensive metric of the QKD link. We also propose a novel routing protocol to achieve high-level scalability and minimize consumption of cryptographic keys. Given the limited mobility of nodes in QKD networks, our routing protocol uses the geographical distance and calculated link states to determine the optimal route. It also benefits from a caching mechanism and detection of returning loops to provide effective forwarding while minimizing key consumption and achieving the desired utilization of network links. Simulation results are presented to demonstrate the validity and accuracy of the proposed solutions

The Case for Quantum Key Distribution

Quantum key distribution (QKD) promises secure key agreement by using quantum mechanical systems. We argue that QKD will be an important part of future cryptographic infrastructures. It can provide long-term confidentiality for encrypted information without reliance on computational assumptions. Although QKD still requires authentication to prevent man-in-the-middle attacks, it can make use of either information-theoretically secure symmetric key authentication or computationally secure public key authentication: even when using public key authentication, we argue that QKD still offers stronger security than classical key agreement.Comment: 12 pages, 1 figure; to appear in proceedings of QuantumComm 2009 Workshop on Quantum and Classical Information Security; version 2 minor content revision

Improvement of continuous-variable quantum key distribution systems by using optical preamplifiers

Continuous-variable quantum key distribution protocols, based on Gaussian modulation of the quadratures of coherent states, have been implemented in recent experiments. A present limitation of such systems is the finite efficiency of the detectors, which can in principle be compensated for by the use of classical optical preamplifiers. Here we study this possibility in detail, by deriving the modified secret key generation rates when an optical parametric amplifier is placed at the output of the quantum channel. After presenting a general set of security proofs, we show that the use of preamplifiers does compensate for all the imperfections of the detectors when the amplifier is optimal in terms of gain and noise. Imperfect amplifiers can also enhance the system performance, under conditions which are generally satisfied in practice.Comment: 11 pages, 7 figures, submitted to J. Phys. B (special issue on Few Atoms Optics

Quantum Forbidden-Interval Theorems for Stochastic Resonance

We extend the classical forbidden-interval theorems for a stochastic-resonance noise benefit in a nonlinear system to a quantum-optical communication model and a continuous-variable quantum key distribution model. Each quantum forbidden-interval theorem gives a necessary and sufficient condition that determines whether stochastic resonance occurs in quantum communication of classical messages. The quantum theorems apply to any quantum noise source that has finite variance or that comes from the family of infinite-variance alpha-stable probability densities. Simulations show the noise benefits for the basic quantum communication model and the continuous-variable quantum key distribution model.Comment: 13 pages, 2 figure

Quantum Eavesdropping without Interception: An Attack Exploiting the Dead Time of Single Photon Detectors

The security of quantum key distribution (QKD) can easily be obscured if the eavesdropper can utilize technical imperfections of the actual implementation. Here we describe and experimentally demonstrate a very simple but highly effective attack which even does not need to intercept the quantum channel at all. Only by exploiting the dead time effect of single photon detectors the eavesdropper is able to gain (asymptotically) full information about the generated keys without being detected by state-of-the-art QKD protocols. In our experiment, the eavesdropper inferred up to 98.8% of the key correctly, without increasing the bit error rate between Alice and Bob significantly. Yet, we find an evenly simple and effective countermeasure to inhibit this and similar attacks