A spaceship with a thruster - one body, one force

A spaceship with one thruster producing a constant magnitude force is analyzed for various initial conditions. This elementary problem, with one object acted upon by one force, has value as a challenge to one's physical intuition and in demonstrating the benefits and limitations of dimensional analysis. In addition, the problem can serve to introduce a student to special functions, provide a mechanical model for Fresnel integrals and the associated Cornu spiral, or be used as an example in a numerical methods course. The problem has some interesting and perhaps unexpected features.Comment: 8 pages, 12 figures. Submitted to the American Journal of Physics. After it is published, it will be found at http://scitation.aip.org/aj

Arteriolopatía calcificante urémica, reporte de un caso tratado con tiosulfato de sodio

We describe a case of calcific uremic arteriolopathyinitially associated with skin lesions within the context of a patient with chronic kidney disease on automated peritoneal dialysis therapy. Among the most relevant findings, the patient hadhyperphosphatemia, normocalcemia and severe hyperparathyroidism without nodular hyperplasia. Clinical improvement with multimodal management of enhancement in dialysis therapy and intravenous sodium thiosulfate is highlighted. Calciphylaxis is a disorder that has a high morbidity and mortality, secondary to sepsis. It occurs more frequently in patients with chronic renal failure who are on hemodialysis. It is characterized by systemic medial calcification of the arterioles, triggering ischemia and subcutaneous necrosis of skin and soft tissues. Histopathological evaluation helps to confirm the diagnosis.Describimos un caso de arteriolopatía calcificante urémica asociada,  inicialmente, a lesiones cutáneas,en unpaciente con insuficiencia renal crónica, en terapia de diálisis peritoneal automatizada, como hallazgos másrelevantes presentaba hiperfosfatemia, normocalcemia e hiperparatiroidismo severo sin hiperplasia nodular.Se destaca la mejoría clínica con manejo multimodal de intensificación en la terapia dialítica y tiosulfato desodio intravenoso.La calcifilaxis es un trastorno que debuta con alta morbilidad ymortalidad, secundaria a sepsis, ocurre con mayor frecuencia en pacientes con insuficiencia renal crónica que se encuentran en hemodiálisis. Se caracteriza por calcificación sistémica en la media de las arteriolas, desencadenándose isquemia y necrosis subcutánea de piel y tejidos blandos. La evaluación histopatológica ayuda a confirmar el diagnóstico

Overview of processing techniques for surface electromyography signals

Surface electromyography (sEMG) is a technology to assess muscle activation, which is an important component in applications related to diagnosis, treatment, progression assessment, and rehabilitation of specific individuals' conditions. Recently, sEMG potential has been shown, since it can be used in a non-invasive manner; nevertheless, it requires careful signal analysis to support health professionals reliably. This paper briefly described the basic concepts involved in the sEMG, such as the physiology of the muscles, the data acquisition, the signal processing techniques, and classification methods that may be used to identify disorders or signs of abnormalities according to muscular patterns. Specifically, classification methods encompass digital signal processing techniques and machine learning with high potential in the field. We hope that this work serves as an introduction to researchers interested in this field.Comment: 11 pages, 7 figure

Post-Traumatic Stress Associated with Telework-Related Job Limitation in Latin America

During the pandemic, there has been evidence of work limitations during telework, which are believed to cause mental health problems. Our objective was to assess the association between perceived work limitations during telework and posttraumatic stress during the COVID-19 pandemic in Latin America. A cross-sectional study was conducted in Latin America in 2020. Exposure was measured by self-reporting using a self-perception questionnaire; the SPRINT-E questionnaire was used for outcome measurements. Generalized linear models were applied. Of 1329 participants, 15.2% (n = 202) had posttraumatic stress. In a multivariate analysis, the highest frequency of posttraumatic stress was found among those with moderate depression or more (PR = 1.29; 95% CI: 1.03–1.61), moderate or more anxiety (PR = 2.34; 95% CI: 1.61–3.41), and moderate or more stress (PR = 2.45; 95% CI: 1.46–4.12). In conclusion, there is an association between perceived work limitations during telework and posttraumatic stress in Latin American workers. For this reason, it is recommended that occupational physicians, companies, and institutions assess the frequency of posttraumatic stress and monitor the mental health of workers.National Institute of Mental HealthRevisión por pare

Estudio farmacognósico para el cuidado de la salud a partir de aceites esenciales obtenidos por destilación de arrastre de vapor

La medicina natural aborda de forma considerable el conocimiento etnobotánico de las plantas medicinales a partir del estudio de sus principios activos, mediante técnicas de fotoquímica en la aplicación de los diferentes campos de la salud. La producción de plantas medicinales y aromáticas resulta rentable cuando se le da un valor agregado a la producción primaria, es decir, se comercializan no como drogas vegetales frescas o secas, sino procesadas y transformadas de donde se obtienen extractos, aceites o pueden elaborarse fitomedicamentos, fitocosméticos, etc. Se realizó un estudio con abordaje experimental, donde se tomó como referente algunas especies del género Ocimum pertenecientes a la familia Labiatae (Lamiaceae) cultivadas en el departamento de Risaralda

Neumotórax espontáneo idiopático secundario a neumotórax catamenial no asociado a endometriosis: reporte de caso

El neumotórax espontáneo idiopático constituye una causa poco frecuente de neumotórax, si se le atribuyen causas no pulmonares como el neumotórax catamenial y/o neumotórax catamenial no asociado a endometriosis, esta condición se hace aún más rara. El abordaje terapéutico está en estrecha relación al control de las complicaciones generadas por el neumotórax. Se presenta a continuación el caso de una paciente femenina de 34 años, quien debuta con su primer episodio de neumotórax espontáneo, el cual se presume a características catameniales por la coincidencia con el ciclo menstrual de la misma

Neumotórax espontáneo idiopático secundario a neumotórax catamenial no asociado a endometriosis: reporte de caso

Idiopathic spontaneous pneumothorax is a rare cause of pneumothorax, if non-pulmonary causes such as catamenial pneumothorax and/or catamenial pneumothorax not associated with endometriosis are attributed to it, this condition becomes even rarer. The therapeutic approach is closely related to the control of the complications generated by the pneumothorax. The following is the case of a 34-year-old female patient, who debuts with her first episode of spontaneous pneumothorax, which is presumed to have catamenial characteristics due to the coincidence with her menstrual cycle.El neumotórax espontáneo idiopático constituye una causa poco frecuente de neumotórax, si se le atribuyen causas no pulmonares como el neumotórax catamenial y/o neumotórax catamenial no asociado a endometriosis, esta condición se hace aún más rara. El abordaje terapéutico está en estrecha relación al control de las complicaciones generadas por el neumotórax. Se presenta a continuación el caso de una paciente femenina de 34 años, quien debuta con su primer episodio de neumotórax espontáneo, el cual se presume a características catameniales por la coincidencia con el ciclo menstrual de la misma

The Seventeenth Data Release of the Sloan Digital Sky Surveys: Complete Release of MaNGA, MaStar and APOGEE-2 Data

This paper documents the seventeenth data release (DR17) from the Sloan Digital Sky Surveys; the fifth and final release from the fourth phase (SDSS-IV). DR17 contains the complete release of the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, which reached its goal of surveying over 10,000 nearby galaxies. The complete release of the MaNGA Stellar Library (MaStar) accompanies this data, providing observations of almost 30,000 stars through the MaNGA instrument during bright time. DR17 also contains the complete release of the Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2) survey which publicly releases infra-red spectra of over 650,000 stars. The main sample from the Extended Baryon Oscillation Spectroscopic Survey (eBOSS), as well as the sub-survey Time Domain Spectroscopic Survey (TDSS) data were fully released in DR16. New single-fiber optical spectroscopy released in DR17 is from the SPectroscipic IDentification of ERosita Survey (SPIDERS) sub-survey and the eBOSS-RM program. Along with the primary data sets, DR17 includes 25 new or updated Value Added Catalogs (VACs). This paper concludes the release of SDSS-IV survey data. SDSS continues into its fifth phase with observations already underway for the Milky Way Mapper (MWM), Local Volume Mapper (LVM) and Black Hole Mapper (BHM) surveys