A transient and non-unit-based protection technique for DC grids based on the rate-of-change (R-o-C) of the fault induced travelling wave components

This paper presents a transient and non-unit-based protection scheme for consideration in DC grids of the future. The technique utilises the rate-of-change (R-o-C) of the associated travelling wave components following the occurrence of a fault to determine whether the fault is internal or external. For an internal fault, the product of the magnitude of the R-o-C of the fault induced voltage and current travelling wave following fault inception must exceed a predetermined setting, otherwise the fault is external. The DC inductor located at the cable ends provides attenuation for the high frequency contents of the fault generated components resulting from an external fault. The ratio between the forward voltage travelling wave and the backward voltage travelling wave provides directional discrimination. This ratio is less than unity for a forward directional fault and greater than unity for reverse directional faults. The protection algorithm has been validated using PSCAD/EMTDC simulations based on full scale modular multilevel converter (MMC)-based HVDC grid. The simulation results presented, including the performances indices compared to existing and proposed methods available in literature utilising the derivative of the fault induced components show the suitability and reliability of the proposed technique in distinguishing between internal and external faults. Key advantages of the proposed technique is that it simple, easily implemented, and does not rely on complex signal processing technique; and therefore it can easily be implemented to provide autonomous tripping for all relays located on the DC grid.</p

Addressing challenges of water resilience: a study of water security risk in pastoralist households in Kenya

Pastoralist communities in Northern Kenya face increasing water security risks attributable to disruptions in their hydro-climatic and socio-ecological environments. Sedentary pastoralists, women and children are most vulnerable to spatial-temporal variations in water availability. This vulnerability is exacerbated by embedded power relations within existing socio-cultural and water governance systems. A preliminary study carried out in 2015/16 examined pastoralist women’s disempowerment in relation to the domestic water security constraints they face. The research found subjective evidence that women with diversified livelihoods and social capital are more resilient to water stress. The follow on study being carried out in 2018 builds on these findings and is aiming to provide empirical evidence on factors behind water security and factors that enhance resilience for vulnerable pastoralist communities. The study is being carried out in both urban and rural communities in Samburu County and is applying a mixed methods research methodology incorporating both quantitative and innovative, qualitative research approaches

La confrerie ni‘matullahiyya en Iran

The Ni‘matullahiyya Brotherhood was founded in Uzbekistan by Shah Nur al-Din Ni‘matullah in 1360 before being transferred to Iran. Its current master is Dr Javad Nurbakhsh who has been responsible for the opening of several assembly houses. Every house has the same structure and organisation with two weekly assemblies.The relation with the master is fundamental and the novices perform rituals which bind them to the brotherhood. Focusing on the interiority of the Way, the brotherhood shows little interest in the outside world

Ecocardiografía intracardíaca. Nuevas aplicaciones

The intracardiac echo transducer was first described in 1960(1), approved by the FDA in 1997 for the guidance of interventional procedures in the cath lab and electrophysiology. It is an imaging technique that is an alternative to transoesophageal echocardiography, with the following advantages: No need for general anesthesia. It provides short scan time. It has a high quality picture. Its usefulness noted for the high-resolution images and flexibility of movement of the catheter with capacity to move in four directions. The system consists of a probe with a transducer monoplanar 64-element 110 cm long and 8 to 10 Fr with two moving rings allowing mobilization. It is important to handle the probe and the organization’s cath lab for use. Indications are innovative, usually comprising using intracardiac intravascular probe as a guide for fenestration in aortic dissection type A in malperfusion syndrome, transcatheter aortic valve implantation, endocarditis assessment electrode electrical stimulation systems, biopsy right intracardiac masses and performing portosystemic shunts in patients with liver cirrhosis refractory to treatment. The intracardiac echo, like the other cardiac imaging techniques, continues to evolve, and have recently been able to image in three dimensional (3D). The emergences of 3D probe will in the near future, an extension of its indications to guide invasive procedures. This imaging technique has a promising future so it must be the knowledge of clinical cardiologists, echocardiography, interventional cardiologists and interventional radiologistsEl transductor de la ecocardiografía intracardíaca se describió por primera vez en 1960(1), aprobado por la FDA en 1997 para la guía de procedimientos de intervención en hemodinámica y electrofisiología. La ecocardiografía intracardíaca es una técnica de imagen que surge como alternativa a la ecocardiografía transesofágica con las siguientes ventajas: No necesita de anestesia general. Proporciona tiempo corto de exploración. Tiene una elevada calidad de imagen. Su utilidad destaca por la alta resolución de imágenes y la flexibilidad de movimientos del catéter con capacidad de moverse en cuatro direcciones. El sistema consta de una sonda monoplanar con un transductor de 64 elementos de 110 cm de largo y de 8 a 10 Fr con dos anillos móviles que permiten su movilización. Es importante conocer el manejo de la sonda y la organización del laboratorio de hemodinámica para su uso. Existen indicaciones innovadoras, que comprenden usualmente el uso intravascular de la sonda intracardíaca como guía para la fenestración en la disección aórtica tipo A en síndrome de malperfusión, implante de válvula aórtica transcateter, evaluación de endocarditis, en electrodos de sistemas de estimulación eléctrica, biopsia de masas intracardíacas derechas y en la realización de cortocircuitos portosistémicos en pacientes con cirrosis hepática refractaria a tratamiento. La ecocardiografía intracardíaca, al igual que el resto de las técnicas de imagen cardíaca, sigue evolucionando y recientemente se ha logrado obtener imágenes tridimensionales (3D). La aparición de la sonda 3D permitirá en el futuro mediato una ampliación de sus indicaciones para guiar procedimientos invasivos. Esta técnica de imagen tiene un futuro prometedor, por lo que debe ser del conocimiento de médicos cardiólogos clínicos, ecocardiografistas, cardiólogos intervencionistas y radiólogos intervencionistas

Effects of polyethylene microplastics and Salmonella enterica Typhimurium co-exposure in ceca of broiler chickens

Microplastics (MPs) are plastic fragments less than 5 mm that have been implicated in negative health impacts following exposure. MPs are increasingly being found in locations where there could be an interaction with pathogens such as Salmonella enterica Typhimurium. This study aimed to elucidate the interaction of polyethylene MPs and S. Typhimurium and how this co-exposure alters the cecal microbiome. We focused on polyethylene MPs which is one of the most abundant plastics found in the environment and in food packaging materials. We assessed two common forms of polyethylene: powder and fiber. For this study, we utilized chicken cecal mesocosms (n=60) for a 24 h co-exposure. 16S community sequencing results indicate that polyethylene fiber treatment groups with and without S. Typhimurium had greater changes to cecal taxonomic composition following a 24 h exposure. However, changes in the total metabolome were primarily driven by the presence of S. Typhimurium. Further experiments will be needed with this in vitro cecal microbiome model to indicate if and how a high concentration of polyethylene microplastics and S. Typhimurium will lead to phenotypes for gastrointestinal disorders. This will give insight into human health implications from consumption of or interaction with chicken contaminated with this co-exposure

Elaboración de Instrumentos de Evaluación para aplicar a estudiantes de Enseñanza Básica en Plan de estudio Actual por Pandemia

Este trabajo tiene como finalidad mostrar una forma de Evaluar un proceso de aprendizaje aplicado de manera remota, por medio de uso de tecnologías virtuales y el uso de redes y aplicaciones Online que entregan además los diferentes recursos institucionales virtuales dentro del uso de correo institucional y acorde a las habilidades que se establecen en la visión y misión escolar, todo ello acorde a los avances tecnológicos que requieren desarrollar y aplicar como estudiantes del siglo XXI. Este proceso de evaluación es aplicado en cuatro asignaturas del Plan de Estudio Priorizado acorde al contexto de un establecimiento de Enseñanza Básica, en la Isla de Chiloé , con un entorno Pandémico en el cual nos encontramos actualmente a nivel mundial, el cual tiene como propósito ver la evaluación como un proceso que haga que cada alumno y alumna evidencie sus propios avances y logros, esto inicialmente de manera formativa, que posteriormente se aplique en lo curricular, y donde éste proceso deje de ser visto como punitivo y que además hace cambiar todos los paradigmas vistos en periodos académicos normales, además considera una retroalimentación virtual con los estudiantes, donde analizan resultados individuales previamente remitidos y que complementan con comentarios o dudas

Naisten mahdollisuudet päästä valmiusyksikkö Karhuun ja VATI- ryhmiin

Poliisin erityistoimintayksiköissä valmiusyksikkö Karhussa ja vaativien tilanteiden ryhmissä eli VATI- ryhmissä ei ole koskaan työskennellyt naisia, eivätkä naispoliisit ole niihin hakeutuneet. Opinnäytetyön tarkoitus on selvittää, olisiko naisten mahdollista päästä työskentelemään poliisin fyysisesti vaativimmissa tehtävissä. Lisäksi pohditaan syitä sille, miksi naiset eivät ole käyneet valmiusyksikön tai VATI- ryhmien pääsykokeissa. Työssä tarkastellaan myös sitä, miten naispoliisien suhteellisen osuuden kasvaminen vaikuttaa poliisin erityistoimintayksiköiden tulevaisuuteen. Opinnäytetyön salassapito ja turvallisuusluokka perustuvat tutkimuslupapäätöksiin, 28.04.2022 (POL-2022-47707) sekä 24.10.2022 (POL-2022-110619). Opinnäytetyö toteutettiin laadullisella menetelmällä haastattelututkimuksena. Haastatteluita varten oli myönnetty tutkimusluvat Helsingin poliisilaitokselta ja Poliisiammattikorkeakoululta. Haastateltavina oli viisi valmiusyksikön ja VATI- ryhmien erityisasiantuntijaa. Haastateltavat osallistuivat tutkimukseen vapaaehtoisesti, ja heille oli annettu opinnäytetyön tutkimussuunnitelma ja haastattelukysymykset etukäteen luettaviksi. Naisten hakemiselle valmiusyksikköön tai VATI- ryhmiin ei ole estettä. Naisten toivottaisiin hakeutuvan edellä mainittuihin yksiköihin. On selvää, että yksiköiden fyysiset pääsyvaatimukset tuottavat naisille suurempia haasteita kuin miehille. Pääsyvaatimuksia ei haluta muuttaa, koska ne mittaavat tarkoituksenmukaisesti sitä, miten hakija selviää vaativissa työtehtävissä. Toistaiseksi erityistoimin-tayksiköihin hakevien poliisimiesten taso on ollut korkea. Opinnäytetyön aihetta ei ole tutkittu Suomessa aiemmin, eikä naisten rekrytoimista poliisin erityistoimintayksiköihin ole edistetty. Olisi tarpeellista selvittää syitä sille, miksi naiset eivät hakeudu erityistoimintayksiköiden pääsykokeisiin. Jatkotutkimusta vaatisi myös se, miten naispoliisien osuuden kasvaminen vaikuttaa poliisin erityistoimintayksiköiden rekrytointiin jatkossa – riittääkö fyysiset vaatimukset täyttäviä, vaativiin tehtäviin soveltuvia hakijoita jatkossakin