206 research outputs found
Investment-specific technology shocks and international business cycles: an empirical assessment
In this paper, we first introduce investment-specific technology (IST) shocks into an otherwise standard international real business cycle model and show that a thoughtful calibration of them along the lines of Raffo (2009) successfully addresses several of the existing puzzles in the literature. In particular, we obtain a negative correlation of relative consumption and the terms of trade (Backus-Smith puzzle), as well as a more volatile real exchange rate, and cross-country output correlations that are higher than consumption correlations (price and quantity puzzles). Then we use data from the Organisation for Economic Co-operation and Development for the relative price of investment to build and estimate these IST processes across the United States and a "rest of the world" aggregate, showing that they are cointegrated and well represented by a vector error–correction model. Finally, we demonstrate that, when we fit such estimated IST processes into the model, the shocks are actually powerless to explain any of the existing puzzles.
Characterization of the carnivore community in the EIN Massís de les Salines
L’Espai d’Interès Natural (EIN) del Massís de les Salines és una de les zones més desconegudes de l’Alt Empordà degut a la seva situació i orografia. Es tracta d’una serralada transfronterera amb hàbitats pirinencs i mediterranis on hi trobem el límit de distribució de moltes espècies de fauna i flora. Un dels grups taxonòmics més desconeguts a la zona, degut als seus hàbits nocturns i a la gran massa forestal present al territori, és el dels carnívors. Aquest ordre de mamífers juga un paper clau als ecosistemes, perquè actua com a regulador de les seves preses (Terborgh et al., 2013) i perquè algunes de les seves espècies actuen com a dispersadores de llavors (Rosalino et al., 2010). L’objectiu del present estudi és recollir totes les dades sobre carnívors de l’EIN esmentat generades pel propi autor amb la tècnica del fototrampeig des de l’any 2017 fins al 2022, entre les quals n’hi ha d’obtingudes a la parcel·la del massís de les Salines dins el Pla de seguiment del gat fer i altres mesocarnívors (Grup FELIS, ICHN). A partir de tota aquesta informació s’ha generat un llistat d’espècies de carnívors presents a l’EIN i una taula i dos gràfics que expressen les abundàncies relatives de totes les espècies de mamífer que s’hi van detectar. Com a resultat remarcable, cal fer menció de la presència del turó (Mustela putorius Linnaeus, 1758), una espècie amenaçada i catalogada
com a «en perill d’extinció» a Catalunya, i de la marta (Martes martes Linnaeus, 1758), una espècie de la qual s’ha observat, en els últims anys, que no és una especialista de boscos d’alta muntanya, sinó que es pot trobar a cotes més baixes i cada cop és més freqüent trobar-la-hi (Sayol et al., 2015; Federico, 2019; Guixé et al., 2020).The Area of N atural Interest (EIN, from the Catalan abbreviation) of the Massís de les Salines is one of the most unknown areas of the Alt Empordà region, due to its location and orography. It is a cross-border mountain range with Pyrenean and Mediterranean habitats where
we find the distribution limit of many species. One of the most unknown taxonomic groups in the area, due to its nocturnal habits and the large forest mass present in the territory, is the carnivore community. This order of mammals plays a key role in ecosystems, as it acts as a
regulator of its prey (Terborgh et al., 2013) and certain species, despite being considered carnivores, act as seed dispersers (Rosalino et al. , 2010). The aim of this study is to collect all the data generated by the author himself with the camera trapping technique from 2017 to 2022, which also includes data obtained in the Massís de les Salines plot collected within the «Pla de seguiment del gat fer i altres mesocarnívors» monitoring system (FELIS Group, ICHN). Based on all this information, a list of carnivore species present in the EIN has been generated, as well as the abundances of all detected species and, especially that of carnivores. A remarkable result is the presence of the european polecat (Mustela putorius Linnaeus, 1758), a species threatened and listed as «in danger of extinction» in Catalonia, and of the pine marten (Martes martes Linnaeus, 1758), that in recent years has been observed to be a species that is not only specialized to high mountain forests but can be found more frequently than previously though at lower altitudes (Sayol et al., 2015; Federico, 2019; Guixé et al., 2020)
Movement Behavior and Health Outcomes among Sedentary Adults: A Cross-Sectional Study
Background: Sedentary behavior, which is highly prevalent among office workers, is associated with multiple health disorders, including those of the musculoskeletal and cardiometabolic systems. Although prior studies looked at postures or physical activity during work or leisure time, few analyzed both posture and movement throughout the entire day. Objective: This cross-sectional pilot study examined the movement behavior of sedentary office workers during both work and leisure time to explore its association with musculoskeletal discomfort (MSD) and cardiometabolic health indicators. Methods: Twenty-six participants completed a survey and wore a thigh-based inertial measuring unit (IMU) to quantify the time spent in different postures, the number of transitions between postures, and the step count during work and leisure time. A heart rate monitor and ambulatory blood pressure cuff were worn to quantify cardiometabolic measures. The associations between movement behavior, MSD, and cardiometabolic health indicators were evaluated. Results: The number of transitions differed significantly between those with and without MSD. Correlations were found between MSD, time spent sitting, and posture transitions. Posture transitions had negative correlations with body mass index and heart rate. Conclusions: Although no single behavior was highly correlated with health outcomes, these correlations suggest that a combination of increasing standing time, walking time, and the number of transitions between postures during both work and leisure time was associated with positive musculoskeletal and cardiometabolic health indicators among sedentary office workers and should be considered in future research
DeepPCR: Parallelizing Sequential Operations in Neural Networks
Parallelization techniques have become ubiquitous for accelerating inference
and training of deep neural networks. Despite this, several operations are
still performed in a sequential manner. For instance, the forward and backward
passes are executed layer-by-layer, and the output of diffusion models is
produced by applying a sequence of denoising steps. This sequential approach
results in a computational cost proportional to the number of steps involved,
presenting a potential bottleneck as the number of steps increases. In this
work, we introduce DeepPCR, a novel algorithm which parallelizes typically
sequential operations in order to speed up inference and training of neural
networks. DeepPCR is based on interpreting a sequence of steps as the
solution of a specific system of equations, which we recover using the Parallel
Cyclic Reduction algorithm. This reduces the complexity of computing the
sequential operations from to , thus
yielding a speedup for large . To verify the theoretical lower complexity of
the algorithm, and to identify regimes for speedup, we test the effectiveness
of DeepPCR in parallelizing the forward and backward pass in multi-layer
perceptrons, and reach speedups of up to for the forward and
for the backward pass. We additionally showcase the flexibility of
DeepPCR by parallelizing training of ResNets with as many as 1024 layers, and
generation in diffusion models, enabling up to faster training and
faster generation, respectively, when compared to the sequential
approach
Dual labor markets in Spain: a firm-side perspective
Usando microdatos contables, en este trabajo documentamos el uso de los contratos temporales e indefinidos por las empresas españolas entre 2004 y 2019. Mostramos que el uso de contratos temporales es muy heterogéneo entre distintas empresas y que la distribución de la tasa de temporalidad está muy sesgada hacia la derecha: la ratio de temporalidad mediana es de tan solo el 3 %, mientras que la tasa media es del 18 %. Parte de esta variación está asociada con el sector y la región en los que opera la empresa, así como con el ciclo macroeconómico. Sin embargo, aproximadamente el 80 % de la variación viene explicada por diferencias entre empresas pertenecientes al mismo sector, la misma región y el mismo punto del ciclo. Individualmente, incluso tras controlar por el sector y la región, observamos que las empresas más grandes y las más jóvenes son las que hacen un mayor uso de los contratos temporales.Using comprehensive balance-sheet data for Spain, we document the use of fixed-term and open-ended contracts by firms over the period 2004-2019. We show that the use of temporary contracts is very heterogeneous across firms, with the distribution of the temporary share being severely right-skewed: the median share of temporary employment is only 3%, while the average is 18%. Part of this variation is related to the sector and region where firms operate as well as to the macroeconomic cycle. However, around 80% of the variation reflects differences across firms operating in the same industry, in the same location and at the same point of the business cycle. At the individual level, even after controlling for sector and region, we observe that larger and younger firms make more extensive use of temporary contracts
Scaffold-based bone tissue engineering in microgravity: potential, concerns and implications
One of humanity’s greatest challenges is space exploration, which requires an in-depth analysis of the data continuously collected as a necessary input to fill technological gaps and move forward in several research sectors. Focusing on space crew healthcare, a critical issue to be addressed is tissue regeneration in extreme conditions. In general, it represents one of the hottest and most compelling goals of the scientific community and the development of suitable therapeutic strategies for the space environment is an urgent need for the safe planning of future long-term manned space missions. Osteopenia is a commonly diagnosed disease in astronauts due to the physiological adaptation to altered gravity conditions. In order to find specific solutions to bone damage in a reduced gravity environment, bone tissue engineering is gaining a growing interest. With the aim to critically investigate this topic, the here presented review reports and discusses bone tissue engineering scenarios in microgravity, from scaffolding to bioreactors. The literature analysis allowed to underline several key points, such as the need for (i) biomimetic composite scaffolds to better mimic the natural microarchitecture of bone tissue, (ii) uniform simulated microgravity levels for standardized experimental protocols to expose biological materials to the same testing conditions, and (iii) improved access to real microgravity for scientific research projects, supported by the so-called democratization of space.Peer ReviewedPostprint (published version
Lower Limb Kinematics in Individuals with Hip Osteoarthritis during Gait: A Focus on Adaptative Strategies and Interlimb Symmetry
Among the functional limitations associated with hip osteoarthritis (OA), the alteration of gait capabilities represents one of the most invalidating as it may seriously compromise the quality of life of the affected individual. The use of quantitative techniques for human movement analysis has been found valuable in providing accurate and objective measures of kinematics and kinetics of gait in individuals with hip OA, but few studies have reported in-depth analyses of lower limb joint kinematics during gait and, in particular, there is a scarcity of data on interlimb symmetry. Such aspects were investigated in the present study which tested 11 individuals with hip OA (mean age 68.3 years) and 11 healthy controls age- and sex-matched, using 3D computerized gait analysis to perform point-by-point comparisons of the joint angle trends of hip, knee, and ankle. Angle-angle diagrams (cyclograms) were also built to compute several parameters (i.e., cyclogram area and orientation and Trend Symmetry) from which to assess the degree of interlimb symmetry. The results show that individuals with hip OA exhibit peculiar gait patterns characterized by severe modifications of the physiologic trend at hip level even in the unaffected limb (especially during the stance phase), as well as minor (although significant) alterations at knee and ankle level. The symmetry analysis also revealed that the effect of the disease in terms of interlimb coordination is present at knee joint as well as hip, while the ankle joint appears relatively preserved from specific negative effects from this point of view. The availability of data on such kinematic adaptations may be useful in supporting the design of specific rehabilitative strategies during both preoperative and postoperative periods
Ciudadanía e inclusión social de los jóvenes : Tutorías laborales y educativas en la Provincia de Buenos Aires
La ponencia propone un diseño de política pública para los jóvenes que dejan percibir la Asignación Universal por Hijo (AUH), cuando los beneficiarios cumplen la mayoría de edad. Al finalizar dicha cobertura, los jóvenes inician una etapa en la que deben emprender diferentes caminos laborales, educativos y familiares, pudiendo desconocer las posibilidades de apoyo y herramientas que las organizaciones estatales e intermedias les ofrecen. En este sentido, proponemos desde un enfoque estratégico, la implementación de un Programa Provincial que brinde a los jóvenes, la preparación necesaria para las elecciones que caracterizan el ingreso a la nueva etapa de inserción social que experimentarán. Esta preparación se materializará a través del conocimiento de las distintas posibilidades laborales y educativas con las que cuentan los jóvenes, y en el acompañamiento necesario para hacer efectivo el acceso a las alternativas, según "mundos de vida" y trayectorias singulares de los sujetos. Desde una perspectiva constructiva y sociohistórica, los jóvenes irán adquiriendo autonomía de manera progresiva para el pleno ejercicio de la ciudadanía, a través de un tipo de acompañamiento definido como tutoria
An Immersive Virtual Kitchen Training System for People with Multiple Sclerosis: A Development and Validation Study
Rehabilitation via virtual reality (VR) training tools allows repetitive, intensive, and task-specific practice in a controlled and safe environment. Our goal was to develop and validate a novel immersive VR system based on the practice of real-life activities in a kitchen environment in people with multiple sclerosis (pwMS) with upper-limb dysfunction. The novel immersive VR kitchen application includes several tasks, i.e., tidying up the kitchen, preparing a hamburger and soup meal, and dish washing. Following the development phase, the system was tested for an 8-week intervention period on a small sample of pwMS suffering from upper-limb dysfunction. The Suitability Evaluation Questionnaire for VR systems served as the primary outcome. The scores for enjoyment, sense of comfort with the system, feelings of success and control, realism, easy-to-understand instructions, assists in rehabilitation therapy, were between 4.0 and 4.6, indicating a high satisfaction. The scores for eye discomfort, dizziness, nausea, and disorientation during practice were between 2.8 and 1.3, indicating a low-to-moderate interference of the system. The virtual kitchen training system is feasible and safe for upper-limb training in pwMS and paves the way for future RCTs to examine the benefits of the system compared with standard care, thus improving the functionality of the upper limbs in pwMS
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