Torus knots that cannot be untied by twisting

We give a necessary condition for a torus knot to be untied by a single twisting. By using this result, we give infinitely many torus knots that cannot be untied by a single twisting.Comment: LaTeX, 12 pages, to appear in Revista Matem\'{a}tica Complutens

Parallel mechanical computing: Metamaterials that can multitask

Decades after being replaced with digital platforms, analogue computing has experienced a surging interest following developments in metamaterials and intricate fabrication techniques. Specifically, wave-based analogue computers which impart spatial transformations on an incident wavefront, commensurate with a desired mathematical operation, have gained traction owing to their ability to directly encode the input in its unprocessed form, bypassing analogue-to-digital conversion. While promising, these systems are inherently limited to single-task configurations. Their inability to concurrently perform multiple tasks, or compute in parallel, represents a major hindrance to advancing conceptual mechanical devices with broader computational capabilities. In here, we present a first attempt to simultaneously process independent computational tasks within the same architected structure. By breaking time invariance in a set of metasurface building blocks, multiple frequency-shifted beams are self-generated which absorb notable energy amounts from the fundamental signal. The onset of these tunable harmonics, enables distinct computational tasks to be assigned to different independent "channels", effectively allowing an analogue mechanical computer to multitask

Severe coinfection of dengue and malaria:A case report

KEY CLINICAL MESSAGE: In countries like Sudan, where several infectious diseases are prevalent, health care providers should not be satisfied with initial detection of a single pathogen and whenever it is feasible, they should investigate coinfections. Infections with high mortality or severe morbidity should be prioritized during the differential diagnosis particularly for diseases with similar clinical manifestations to reduce the death and disability rates. However, this requires substantial improvement in the diagnostic capacity.ABSTRACT: Here we report a case of dengue and malaria coinfection from the southeast region of Sudan, bordering Ethiopia and Eritrea. A 25-year-old male from Sudan presented with symptoms of fever, chills, vomiting, and muscle and joint pain. Laboratory investigations confirmed a coinfection of dengue and malaria, which is assumingly not uncommon in areas heavily syndemic with several diseases but it is severely under-detected, underreported, and underestimated. The case has fully recovered after the supportive care for dengue and chemotherapy treatment for malaria. In such a case, it was important to monitor the patient's recovery and the treatment outcome through clinical indicators and laboratory parameters to update the treatment course whenever needed, according to response. The increasing burden and outbreaks of vector-borne diseases including dengue and malaria in Sudan, indicates the need for improving the implementation of the global vector control response that established by the World Health Organization. Additionally, the increasing prevalent of coinfections is urging substantial improvement in the diagnostic capacity in endemic countries.</p