Evidence for Blue Straggler Stars Rejuvenating the Integrated Spectra of Globular Clusters

Integrated spectroscopy is the method of choice for deriving the ages of unresolved stellar systems. However, hot stellar evolutionary stages, such as hot horizontal branch stars and blue straggler stars (BSSs), can affect the integrated ages measured using Balmer lines. Such hot, "non-canonical" stars may lead to overestimations of the temperature of the main sequence turn-off, and therefore underestimations of the integrated age of a stellar population. Using an optimized Hbeta index in conjunction with HST/WFPC2 color-magnitude diagrams (CMDs), we show that Galactic globular clusters exhibit a large scatter in their apparent "spectroscopic" ages, which does not correspond to that in their CMD-derived ages. We find for the first time that the specific frequency of BSSs, defined within the same aperture as the integrated spectra, shows a clear correspondence with Hbeta in the sense that, at fixed metallicity, higher BSS ratios lead to younger "apparent" spectroscopic ages. Thus, the specific frequency of BSSs in globular clusters sets a fundamental limit on the accuracy for which spectroscopic ages can be determined for globular clusters, and maybe for other stellar systems like galaxies. The observational implications of this result are discussed.Comment: 5 pages, 2 figures, 1 table. Accepted for publication in ApJ

A device for quantitative assessment of thumb Ulnar Collateral Ligament injury

Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.Cataloged from PDF version of thesis.Includes bibliographical references (pages 103-105).Injury to the Ulnar Collateral Ligament (UCL) of the thumb, known as "Skier's Thumb," is treated by surgical repair for complete tears, or by splinting for partial tears. Because of this radical difference in treatment options, diagnostic accuracy is critical. The primary mechanism of diagnosis is through a clinical assessment of joint integrity. This method requires a high degree of examiner skill and experience, and is inherently qualitative. Secondary diagnosis through magnetic resonance imaging (MRI) is often required to ensure accurate diagnosis. This additional testing delays the treatment and adds to the cost of care. A method to quantitatively assess the thumb UCL in a clinical setting is desired. This thesis presents the deterministic design of a device to quantitatively measure the stiffness of the thumb UCL. A stepper motor is used to rotate the thumb, while a cantilever load cell is used to measure torque. The device is designed to be operated by the physician, and has alignment features to properly orient the motor axis of rotation. Several safety features were incorporated into the device, including a magnetic breakaway that prevents applied thumb force from exceeding 10 N. The prototype was constructed, and preliminary testing was performed on healthy human subjects. Peak thumb torque was measured at 213.5 ± 19.2 N-mm, and peak stiffness was calculated to be 4.70 ± 0.39 N-mm/degree. Potential pathways for further device testing and improvement are outlined. The Thumb UCL Device has the potential to improve the speed of injury diagnosis and reduce the need for imaging studies.by Thomas Michael Cervantes.S.M

Entity-based scene understanding

Unifying multiple descriptions to determine the details of an everyday event can be a challenging task for humans. Though incorporating other modalities like images or videos can help humans unify such descriptions, this remains a challenging task for computational systems. We define entity-based scene understanding as the task of identifying the entities in a visual scene from multiple descriptions. This task subsumes coreference resolution, bridging resolution, and grounding to produce mutually consistent relations between entity mentions and groundings between mentions and image regions. Using neural classifiers and integer linear program inference, we show that grounding is improved when forced to conform to relation predictions. We introduce the Flickr30k Entities v2 dataset, and show how our methods can be used to automatically generate similarly rich annotations for the MSCOCO dataset

Analysis and design of an adjustable bone plate for mandibular fracture fixation

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2011.Cataloged from PDF version of thesis.Includes bibliographical references (p. 57-59).This thesis presents the design, analysis and testing of a bone plate for mandibular fracture fixation. Conventional bone plates are commonly used to set fractures of the mandible in a surgical setting. If proper alignment between the two bone segments is not achieved, then a malocclusion can result; this condition often causes significant discomfort to the patient, and may require costly and risky revision surgery to repair. Current methods of bone plate fixation require a surgeon to visually align the segments of bone, and once the plate has been affixed to the bone, there is little that can be done to adjust alignment of the fracture. The modified bone plate presented here has a deformable mid-section, with the purpose of allowing a surgeon to compensate for mis-alignment observed after the plate has been affixed to the fractured bone. The mechanics of deformation associated with various adjustment mechanisms was explored analytically, numerically, and experimentally. It was found that in order to plastically deform the adjustable section, a force of 358.8 N is required, compared with a predicted value of 351 N obtained using numerical simulations and 487 N using a fixed-fixed beam model with a concentrated central load. In addition to static tests, a dynamic testing jig has been designed with the intent of evaluating in vitro performance of the modified bone plate. Current ASTM and ISO standards for bone plate testing require forces to be applied to the faces of the bone plate, orthogonal to the direction of loading experienced in vivo. This condition is applicable to long bones such as the humerus or femur, however loading conditions of the mandible are significantly different. The testing jig allows for any bone plate of any shape to be fixed such that a force can be applied in order to simulate the normal in vivo loading conditions. This system could be used to further optimize the design of current and future deformable bone plates before they are incorporated into invasive animal or clinical trials.by Thomas Michael Cervantes.S.B

Gestión del talento humano y desempeño laboral en el Hospital Regional Ayacucho en tiempos de COVID-19, 2021

A propósito, la investigación tuvo como objetivo determinar la relación de la Gestión del talento humano y Desempeño laboral en el Hospital Regional Ayacucho en tiempos de COVID-19, 2021, La investigación alcanzó un enfoque cuantitativo, tipo aplicada y la técnica empleada fue la encuesta, nivel descriptivo correlacional, diseño no experimental transversal. Donde se obtuvieron una muestra de 132 trabajadores tanto asistenciales como administrativos indistintamente de su condición laboral, aplicando encuestas para la variable gestión del talento humano y desempeño laboral; En cuanto a la confiabilidad de Alpha de Cronbach para ambas variables cuyo resultado fue 0.956 y 0.812, respectivamente, y el procesamiento de datos se realizó con el software SPSS (versión 26), obteniendo un resultado de la gestión del talento humano se relaciona directa con el desempeño laboral con rs = 0.390 estableciéndose como una correlación positiva baja y significativa con p= 0.000 < 0.05, es decir si mejora la gestión del talento humano mejora el desempeño laboral, por lo tanto, se rechazó, la hipótesis nula, es decir: Existe relación significativa entre la Gestión del talento humano y Desempeño laboral en el hospital regional Ayacucho en tiempos de COVID-19, 202

Gestión del conocimiento y productividad laboral según los funcionarios de la Dirección Regional de Salud de Ica, 2018

La investigación titulada “Gestión del conocimiento y productividad laboral según los funcionarios de la Dirección Regional de Salud de Ica, 2018” tuvo como objetivo general de determinar la relación que existe entre la gestión del conocimiento y la productividad laboral según los funcionarios de la Dirección Regional de Salud de Ica, 2018. La investigación se desarrolló bajo el enfoque cuantitativo; la investigación fue de tipo básica con un nivel descriptivo y correlacional; diseño no experimental con corte transversal; la muestra estuvo conformada por 136 funcionarios de la Dirección Regional de Salud de Ica, 2018; los instrumentos de medición fueron sometidos a validez (Suficiente para su aplicación para ambos instrumentos) y fiabilidad (fuerte confiabilidad en ambos instrumentos de medición). Se aplicó el estadístico Rho de Spearman para determinar la relación entre las variables, donde el coeficiente de correlacion fue de 0,322 lo cual indicó una correlación positiva débil entre las variables y p = 0.000 < 0.01, por lo que se concluye que existe una relación positiva y significativa entre las variables

Statistical Modelling for Simulating and Interpreting an Egg Packaging Process for Giveaway Mitigation

Giveaway, the excess product being packed into orders, is one of the contributors of revenue loss that pre-packaged food manufacturers care the most. In collaboration with an egg packaging company, this study aims to discover operation rules to mitigate the giveaway in egg orders. For that, two variables have been raised as potential controllable factors of giveaway. One statistical model has been developed to better interpret the experimental results by understanding the underlying rules of the egg grading machine. The experiments have been accurately reproduced by a simulation using the estimated model parameters, which indicates the success of the model. Based on the experiments, we claim that the number of accepted downgrade grades has a significant influence on the final giveaway ratio. Limitations and further potentials of the statistical model have also been discussed

Remarks on Higgs Inflation

We discuss models where the Higgs boson of the electroweak standard model plays the role of the inflaton. We focus on the question of the violation of perturbative unitarity due to the coupling of the Higgs boson either to the Ricci scalar or to the Einstein tensor and discuss the background dependence of the unitarity bounds. Our conclusion is that the simplest model which restricts itself to the standard model Higgs boson without introducing further degrees of freedom has a serious problem. However, in the asymptotically safe gravity scenario, the Higgs boson of the standard model could be the inflaton and no physics beyond the standard model is required to explain both inflation and the spontaneous breaking of the electroweak symmetry of the standard model.Comment: 9 pages. Version 2: Final Phys. Lett. B version, includes further discussion of singlet scala

Measuring axion gradients with photon interferometry (MAGPI)

We propose a novel search technique for axions with a $CP$-violating monopole coupling $\tilde{g}_Q$ to bulk Standard Model charges $Q \in \{B,L,B-L\}$. Gradients in the static axion field configurations sourced by matter induce achromatic circular photon birefringence via the axion-photon coupling $g_{\phi\gamma}$. Circularly polarized light fed into an optical or (open) radio-frequency (RF) Fabry-P\'erot (FP) cavity develops a phase shift that accumulates up to the cavity finesse: the fixed axion spatial gradient prevents a cancellation known to occur for an axion dark-matter search. The relative phase shift between two FP cavities fed with opposite circular polarizations can be detected interferometrically. This time-independent signal can be modulated up to non-zero frequency by altering the cavity orientations with respect to the field gradient. Multi-wavelength co-metrology techniques can be used to address chromatic measurement systematics and noise sources. With Earth as the axion source, we project reach beyond current constraints on the product of couplings $\tilde{g}_Q g_{\phi\gamma}$ for axion masses $m_{\phi} \lesssim 10^{-5} \mathrm{eV}$. If shot-noise-limited sensitivity can be achieved, an experiment using high-finesse RF FP cavities could reach a factor of $\sim 10^{5}$ into new parameter space for $\tilde{g}_Q g_{\phi\gamma}$ for masses $m_\phi \lesssim 4\times 10^{-11} \mathrm{eV}$.Comment: 9 pages, 2 figures. Published versio

Inflammation and Immune Evasion Coexist in Treponema Pallidum-infected Skin

Syphilis is a systemic, multistage, sexually transmitted infection caused by the highly invasive spirochetal bacterium, Treponema pallidum, subspecies pallidum. In the United States, the annual rate of primary and secondary syphilis (SS) between 2002 and 2016 has increased from 2.1 to 8.7 cases per 100,000.1 Gestational and congenital syphilis cases have also increased in the last few years. There is no evidence of a change in T pallidum susceptibility to penicillin as an explanation for the significant increase in the number of syphilis cases in the United States. It is more likely that changes in risk-taking behavior in the general population are responsible for this change. Although syphilis is easily treatable with penicillin, if left untreated up to one-third of syphilitic patients will go on to have the typical complications associated with tertiary syphilis. It is therefore critically important for clinicians to be well versed in the classic and not so classic dermatologic manifestations of the disease