Non-closed acoustic cloaking devices enabled by sequential-step linear coordinate transformations

Hitherto acoustic cloaking devices, which conceal objects externally, depend on objects\u27 characteristics. Despite previous works, we design cloaking devices placed adjacent to an arbitrary object and make it invisible without the need to make it enclosed. Applying sequential linear coordinate transformations leads to a non-closed acoustic cloak with homogeneous materials, creating an open invisible region. Firstly, we propose to design a non-closed carpet cloak to conceal objects on a reflecting plane. Numerical simulations verify the cloaking effect, which is completely independent of the geometry and material properties of the hidden object. Moreover, we extend this idea to achieve a directional acoustic cloak with homogeneous materials that can render arbitrary objects in free space invisible to incident radiation. To demonstrate the feasibility of the realization, a non-resonant meta-atom is utilized which dramatically facilitated the physical realization of our design. Due to the simple acoustic constitutive parameters of the presented structures, this work paves the way toward realization of non-closed acoustic devices, which could find applications in airborne sound manipulation and underwater demands

PREGLED ODRŽIVOGA RAZVOJA I ODRŽIVOSTI OKOLIŠA U RUDARSKOJ DJELATNOSTI

A comprehensive systemic approach is needed to make effective decisions for global sustainability. The system’s points of view introduced sustainable development (S.D.) and sustainability in prior years. Sustainable development is expressed as a desire followed by humanity to live in a better condition considering all the limits that nature could have. Social, environmental, and economic responsibilities are the wide-ranging developmental characteristics that form sustainability. In this paper, with the help of search engines like Scopus and Web of Science, several documents related to environmental sustainability in the mining industry were studied. The principal investigated problems were tailings dam failure, forestland use in mining operations, social and environmental issues in crushed stone mining industries, landfill mining challenges, climatic problems, economic problems, and fatalities in artisanal and small-scale mines. Also, a table was designed to categorise these problems and determine the solution and primary goal. This study investigates the severity of mining operation conditions and environmental issues in this industry. The common environmental problems in the mining industry include soil degradation, deforestation, land subsidence, acid mine drainage, waste production, natural landscape destruction, coal production, carbon footprint, dust pollution, greenhouse gas emissions and climatic problems. To have a more sustainable mining industry, all the mining stages, from the exploration to the post-closure stages, must minimise resource and energy consumption and waste products.Za donošenje učinkovitih odluka u sklopu globalne održivosti potreban je sveobuhvatan sustavan pristup, što posebno dolazi do izražaja prethodnih godina. Održivi razvoj izražava se kao želja čovječanstva za životom u boljim uvjetima uzimajući u obzir moguća ograničenja prirode. Društvene, ekološke i ekonomske odgovornosti ubrajaju se među brojne karakteristike razvoja koje čine održivost. U ovome radu, uz pomoć tražilica poput Scopusa i Web of Science, proučavano je nekoliko dokumenata vezanih uz održivost okoliša u rudarskoj industriji. Glavni fokusi studija vezani su uz probleme kao što su klizanje jalovišta, korištenje šumskoga zemljišta u rudarskim radovima, socijalna i ekološka pitanja u eksploataciji i proizvodnji tehničko-građevnoga kamena, izazovi eksploatacije na odlagalištima, klimatski problemi, ekonomski problemi i smrtni slučajevi u privatnim i malim rudnicima. Također, osmišljena je tablica koja kategorizira te probleme i njihova rješenja te primarni cilj. Ova studija istražuje važnost radnih uvjeta u rudarstvu i probleme okoliša u rudarskoj industriji. Uobičajeni ekološki problemi u toj industriji uključuju degradaciju tla, krčenje šuma, slijeganje zemljišta, odvodnju kiselih otpadnih voda iz rudnika, proizvodnju otpada, degradaciju prirodnoga krajolika, proizvodnju ugljena, ugljični otisak, onečišćenje prašinom, emisije stakleničkih plinova i klimatske probleme. Kako bismo imali održiviju rudarsku industriju, sve faze rudarstva, od istraživanja do faza nakon zatvaranja, moraju minimizirati potrošnju resursa i energije te otpadne proizvode

Can prodromal symptoms predict recurrence of vasovagal syncope?

Background: Vasovagal syncope (VVS) is a common symptom with empirical therapy and high recurrence rate. Our goal was to determine whether the pattern of presyncopal prodromal symptoms can predict the recurrence probability of vasovagal syncope. Methods: Seventy-nine consecutive patients (male/female: 53/26) with history of VVS and positive tilt table test (TTT) were enrolled in the study and completed the follow-up time for one year. They all had normal electrocardiograms and cardiac echocardiography without underlying disease. All of them were evaluated meticulously for prodromal symptoms (diaphoresis, nausea, palpitation and blurred vision) and frequency of syncopal spells in their past medical history. They received metoprolol at maximum tolerated dose and were taught tilt training as an empirical therapy after TTT. Results: Fifty-four patients (68.4%) reported at least one of the four main prodromal symptoms. Median syncopal ± presyncopal spells were 4 episodes. Forty-two patients (53.2%) experienced recurrence of syncope or presyncope during the follow-up period. In recurrent symptomatic patients, diaphoresis had been more significantly reported in their past medical history (p = 0.018) and they had more syncopal spells before TTT (p = 0.001). Age, gender and type of TTT response did not have any effect on the recurrence of VVS. Conclusions: Patients with a history of diaphoresis as a prodromal symptom and more pretilt syncopal attacks experience more syncopal or presyncopal spells during follow-up

Iranian clinical practice guideline for amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a rapidly progressive neurodegeneration involving motor neurons. The 3–5 years that patients have to live is marked by day-to-day loss of motor and sometimes cognitive abilities. Enormous amounts of healthcare services and resources are necessary to support patients and their caregivers during this relatively short but burdensome journey. Organization and management of these resources need to best meet patients' expectations and health system efficiency mandates. This can only occur in the setting of multidisciplinary ALS clinics which are known as the gold standard of ALS care worldwide. To introduce this standard to the care of Iranian ALS patients, which is an inevitable quality milestone, a national ALS clinical practice guideline is the necessary first step. The National ALS guideline will serve as the knowledge base for the development of local clinical pathways to guide patient journeys in multidisciplinary ALS clinics. To this end, we gathered a team of national neuromuscular experts as well as experts in related specialties necessary for delivering multidisciplinary care to ALS patients to develop the Iranian ALS clinical practice guideline. Clinical questions were prepared in the Patient, Intervention, Comparison, and Outcome (PICO) format to serve as a guide for the literature search. Considering the lack of adequate national/local studies at this time, a consensus-based approach was taken to evaluate the quality of the retrieved evidence and summarize recommendations

Device-Induced Perforation of Right Atrium Following Interventional Closure of Atrial Septal Defect (ASD)

This is a case presentation of a 26-year-old woman with a moderate-sized atrial septal secundum defect (17mm) who underwent catheterism, during which an Amplatzer Septal Occluder number 26 was inserted successfully. On the second postoperative day, she deteriorated and a clinical examination showed a typical tamponade. After a percutaneous aspiration of the pericardial cavity and transient improvement in vital signs, a pig-tail catheter was inserted percutaneously emergently, and the patient was transferred to the operating room in a preshock state. During the operation, an active bleeding point in the superoanterior aspect of the right atrium near the aortic root was detected, which was repaired by direct suture and pericardial patch reinforcement. The Amplatzer device was removed and the atrial septal defect was repaired with a pericardial patch. A lethal complication of the interventional closure of atrial septal defect, properly treated by an emergent intervention and operation, is presented and discussed herein

Iranian clinical practice guideline for amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a rapidly progressive neurodegeneration involving motor neurons. The 3-5 years that patients have to live is marked by day-to-day loss of motor and sometimes cognitive abilities. Enormous amounts of healthcare services and resources are necessary to support patients and their caregivers during this relatively short but burdensome journey. Organization and management of these resources need to best meet patients' expectations and health system efficiency mandates. This can only occur in the setting of multidisciplinary ALS clinics which are known as the gold standard of ALS care worldwide. To introduce this standard to the care of Iranian ALS patients, which is an inevitable quality milestone, a national ALS clinical practice guideline is the necessary first step. The National ALS guideline will serve as the knowledge base for the development of local clinical pathways to guide patient journeys in multidisciplinary ALS clinics. To this end, we gathered a team of national neuromuscular experts as well as experts in related specialties necessary for delivering multidisciplinary care to ALS patients to develop the Iranian ALS clinical practice guideline. Clinical questions were prepared in the Patient, Intervention, Comparison, and Outcome (PICO) format to serve as a guide for the literature search. Considering the lack of adequate national/local studies at this time, a consensus-based approach was taken to evaluate the quality of the retrieved evidence and summarize recommendations