bluuebunny/crossref_metadata_2025 huggingface dataset:
Premenstrual Syndrome Levels and Eating Attitudes Among University Students
Authors:   Department of Nutrition and Dietetics, Faculty of Healthy Sciences, Artvin Çoruh University, Artvin 08000, Turkey, Dokumacioglu Eda
Published: October 2023

Background: Premenstrual syndrome (PMS) is the combination of physical, behavioral, and psychological symptoms that characterize the week leading up to menstruation, and it can last for a few days. This study aimed to investigate irregular PMS, eating attitude behavior, and body mass index values among university students. Methods: The study sample consisted of 140 Artvin Coruh University students studying Nutrition and Dietetics. The study includes questions from three separate sections. The first section contains a sociodemographic characteristic form, the second section consists of the Premenstrual Syndrome Scale (PMSS), and the third section includes the 26-item Eating Attitude Test (EAT-26). Results: In this study, the mean total score for PMSS was 135 ± 38.3, and the mean total score for EAT-26 was 17.0 ± 10.8. Individuals with irregular sleep patterns experienced more severe PMS (p < 0.01) and a shorter daily sleep duration (p < 0.05). Conclusions: High percentages of nutrition and dietetics students in our study experienced PMS, and the incidence of eating disorders was low. The relationship between PMS and EAT-26 must be understood for the health and well-being of university students.
Global simulations of energetic electron excitation of beta-induced Alfvén eigenmodes
Authors: Bao Jian , Zhang Wen-Lu , Li Ding ,   Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
Published: October 2023

The energetic electron (EE) excitation of beta-induced Alfvén eigenmodes is investigated by using the newly developed global eigenvalue code MAS, which is based on a hybrid model that consists of Landau fluid bulk plasma and drift kinetic EE. Specifically, the bulk plasma kinetic effects such as finite Larmor radius, diamagnetic drifts and Landau dampings, and the EE adiabatic fluid response of convection and non-adiabatic kinetic response of precessional drift resonance are incorporated in the simulations. The global eigenmode equation is solved for e-BAE mode structure and linear dispersion relation in tokamak non-perturbatively. The radial width of e-BAE mode structure becomes narrower as the toroidal mode number increases, which can be explained by the change of Alfvén continuous spectra that interact with kinetic Alfvén waves for corresponding eigenmode formation. The e-BAE growth rate exhibits a non-monotonic variation with toroidal mode number for precessional drift resonance destabilization, while the e-BAE real frequency is close to the continuum accumulation point that almost remains the same. The parametric dependence of e-BAE stability on EE density and that on temperature are analyzed by MAS non-perturbative simulations, which shows that the EE density can affect e-BAE real frequency and thus changes the resonance condition, resulting in e-BAE stabilization in the strong EE drive regime. Further, the EE non-perturbative effect on the symmetry breaking of e-BAE mode structure is reported. The poloidal symmetry breaking characterized by the ‘boomerang’ shape two-dimensional (2D) structure can be greatly enhanced by increasing EE temperature, together with the large radial variation of the poloidal phase angle of dominant principal poloidal harmonic. The radial symmetry breaking of e-BAE mode structure arises when EE density/temperature drive is not symmetric with respect to corresponding rational surface, which can lead to a net volume-averaged value of e-BAE parallel wave number which drives plasma intrinsic rotation. These results are helpful in understanding the e-BAE dynamics observed in recent experiments.
A low-frequency wideband ventilation muffler based on an embedded rough-necked Helmholtz resonator
Authors: Li Ting , Wu Feng-Min , Zhang Tong-Tao , Wang Jun-Jun , Yang Bin , Zhang Dong ,   School of Science, Harbin University of Science and Technology, Harbin 150080, China,   School of Instrumentation Science and Engineering, Harbin Institute of Technology, Harbin 150080, China,   School of Physics, Nanjing University, Nanjing 210093, China
Published: October 2023

Aiming at the unsatisfactory low-frequency sound absorption effect of Helmholtz resonator, a novel broadband low-frequency ventilation absorber with rough neck is proposed. The roughness is introduced into the neck of Helmholtz resonator to change the shape of the neck and achieve the structure of rough neck Helmholtz resonator. The proposed absorber can effectively provide the acoustic impedance required for low-frequency sound absorption without changing the overall size, thereby reducing the resonant frequency. The finite element method is used to simulate the structure, and the impedance tube sound absorption test is carried out to verify it. The experimental and simulation results show high consistency with each other. The results also indicate that the rough neck Helmholtz resonator absorber with roughness introduced in the neck achieves an absorption peak at 58 Hz, with an absorption coefficient of about 0.63. Comparing with the absorber without roughness introduced, the resonant peak frequency becomes low, from 70 Hz to 58 Hz, reducing 17.1%. Therefore, adjusting the neck roughness can serve as a method of tuning the acoustic performance, and the absorption peak frequency can be adjusted by appropriately increasing the neck roughness so as to move it in the low frequency direction. Based on the verification that the roughness of the neck can effectively reduce the absorption peak frequency of Helmholtz resonator, a broadband low-frequency ventilation absorber with a rough neck, which is composed of eight absorption units, is designed. Through simulation calculation and experimental exploration, the absorption coefficient can achieve more than 0.8 in a target working frequency band of 500－1100 Hz. On this basis, the acoustic impedance of the structure can be adjusted by introducing roughness into the neck of Helmholtz resonator, so as to obtain the optimized broadband low-frequency ventilation absorber with a rough neck, which achieves a broadband sound absorption coefficient higher than 0.8 in a frequency range of 400–1200 Hz. The optimized structure also has 8 consecutive absorption peaks with amplitudes above 0.95. The proposed low-frequency broadband ventilation absorber provides a reference for designing and optimizing efficient low-frequency subwavelength acoustic absorbers. It has a wide range of applications in pipeline noise control.
General Theory of Quantum Holography Based on Two Photon Interference
Authors: Xu Yao-Kun  , Sun Shi-Hai  , Zeng Yao-Yuan  , Yang Jun-Gang  , Sheng Wei-Dong  , Liu Wei-Tao  ,   1 College of Electronic Science and Technology, National University of Defense Technology, Changsha, 410073, China;,   2 School of Electronics and Communication Engineering, Sun Yat-Sen University, Shenzhen, 518100, China;,   3 College of Sciences, National University of Defense Technology, Changsha, 410073, China
Published: October 2023

As a kind of quantum phenomenon, Hong-Ou-Mandel (HOM) interference is more robust against phase noise. Due to this feature, robust quantum holography emerges, through which wave function of interested photon can be retrieved according to HOM interference pattern. For better understanding and developing this method, we derive a theoretical framework of robust HOM holography. In quantum holography scheme, test state and reference state interfere at beam splitter (BS). Then, degree of freedom (DOF) resolved detections (such as spatial resolved detection, temporal resolved detection or spectrum resolved detection) are applied at the BS output ports, respectively. Based on the single photon detection results, the DOF resolved coincidence counts are postselected, producing interference patterns. The information of the test states is retrieved from the patterns. According to different test states and reference states, four combinations are analysed, including measuring the wave function of single photon state using standard single photon state or coherent state and measuring the wave function of coherent state using standard single photon state or coherent state. In all cases, information of the test states is reflected in normalized second-order correlation function or interference patterns in similar forms. Specially, the wave function of test states can be directly retrieved from the interference patterns, with no complex algorithm required. Besides, phase noise from environment has no influence on this kind quantum holography. Comparison between traditional holography and quantum holography is analysed.
Hawking radiation from a Reissner-Nordstrom-AdS black hole with integral monopoles in extended phase space
Authors: Han Yi-Wen , Hu Cheng , Hong Yun ,   Department of Physics, Chongqing Technology and Business University, Chongqing 400067, China,   College of Basic Teaching, Chengdu Neuss of University, Chengdu 611844, China
Published: October 2023

In recent years, thermodynamics and phase transitions of black holes in extended phase space have been extensively studied. The results show that the original first law of thermodynamics needs revising and new phase transitions will appear. However, so far, Hawking tunneling radiation has not been widely studied in the extended phase space. In particular, whether the tunneling radiation probability changes at this time is still uncertain. This work focuses on this topic, that is, to calculate the specific value of the tunneling probability in the extended phase space and ascertains whether the results obtained in the normal phase space are consistent with those in the extended phase space. The methods used herein are described below. Taking Reissner-Nordstrom-AdS black holes with global monopole for example, the cosmological parameters are regarded as dynamic variables, which is different from previous treatment methods that regard them as constants and ignore their contributions to the tunneling probability. In particular, cosmological parameters are introduced and regarded as thermodynamic pressure when the tunneling probability is calculated, and their contribution to the tunneling probability is considered. In the work the tunneling process of mass particles is mainly studied. The outgoing particles are viewed as spherical de Broglie waves, and then the relative phase velocity and group velocity are calculated. The geodesic equation is obtained according to the relationship between the two velocities, and the tunneling probability is calculated from the geodesic equation. It is concluded that the results show that the tunneling probability of the ingoing particles is proportional to the difference in the Bekenstein-Hawking entropy of the black hole before and after the particles tunnel, and the radiation spectrum deviates from the pure thermal spectrum, which is exactly the same as the case that the cosmological parameters are treated as constants. This means that the tunneling probability of particles can be obtained in the extended phase space, and the tunneling process does not depend on thermodynamic parameters. In addition, it is found that although the global monopole affects the dynamical behavior and thermodynamic quantity of the particle, it does not affect the entropy change or tunneling rate. In other words, the conclusion that the tunneling probability in extended phase space is exactly the same as that in normal phase space does not depend on the space-time topology.
Relationship between coherent population trapping oscillation and Raman detuning
Authors: Han Yan-Chen , Li Yu-Dong , Li Wei ,   Science and Technology on Metrology and Calibration Laboratory, Changcheng Institute of Metrology & Measurement, Aviation Industry Corporation of China, Beijing 100095, China
Published: October 2023

Coherent population trapping (CPT) oscillation is a transient oscillation phenomenon based on the CPT effect, which is related to the Raman detuning of the coherent bichromatic laser fields from the hyperfine ground-states of three-level Λ system. In this work, sawtooth wave is adopted to modulate the frequency of microwave signal to make Raman detuning change uniformly and stepping. Meanwhile, by building the relationship between the microwave frequency modulation rate and the change rate of Raman detuning, the effects of the change rate and mode of Raman detuning on CPT oscillation are analyzed respectively. The results reveal that when the Raman detuning changes uniformly, the CPT oscillation will occur on condition that the change rate is high enough, and the excited oscillations show non-harmonic oscillation behavior. When the Raman detuning is triggered off by step change, the excited CPT oscillation is a damping oscillation, and the oscillation frequency is equal to the frequency of Raman detuning. The modulation of Raman detuning is realized by using sawtooth wave to modulate the microwave frequency, and then the complete establishment of CPT state and the complete attenuation of CPT oscillation process are achieved. This work presents a new modulation method to realize the CPT oscillation, which shows great application potential in the field of weak magnetic measurements and atomic clocks.
Near-infrared self-assembled laser based on Ag2Se quantum dots
Authors: Liao Chen  , Yao Ning  , Tang Lu-Ping  , Shi Wei-Hua  , Sun Shao-Ling  , Yang Hao-Ran  ,   1 College of Electronic and Optical Engineering & College of Flexible Electronics(Future Technology), Nanjing University of Posts and Telecommunications, Nanjing 210023, China;,   2 College of Mechanical and Electronic Engineering, Nanjing Forestry University, Nanjing 210037, China;,   3 SEU-FEI Nano-Pico Center, Key Lab of MEMS of Ministry of Education, Southeast University, Nanjing 210096, China;,   4 Joint International Research Laboratory of Information Display and Visualization, School of Electronic Science and Engineering, Southeast University, Nanjing 210096, China
Published: October 2023

The development of colloidal near-infrared quantum dots (QD) lasers has been hindered by the high state degeneracy of lead salt QDs and the difficulty in coupling colloidal quantum dots to the resonant cavity. In this study, we show that above challenges can be addressed by the self-assembly laser based on Ag2Se QDs. Ag2Se QDs with the lowest quantized states 2-fold degeneracy are used to replace lead salt quantum dots to achieve low threshold near-infrared optical gain. We employ the finite element method to deeply analyze the mode field distribution and oscillation mechanism of the coffee-ring microcavity. Our results reveal that the light field oscillates in a zig-zag path along the cross-sectional area, indicating strong coupling between the QDs and the cavity mode. Furthermore, we investigate the relationship between cavity length and free spectrum range and laser emission wavelength. Leveraging this relationship and the gain spectrum characteristics of Ag2Se QDs, we design a single-mode near-infrared laser and conduct a comprehensive analysis. Using simulation results to fabricate a single-mode near-infrared Ag2Se QD coffee-ring microlaser, which exhibits a linewidth of 0.3 nm and a threshold of 158 μJ cm-2. Currently, it holds the record for the lowest laser threshold among near-infrared colloidal QD lasers. Increasing the laser cavity length, resulting in an increase in the emission wavelength from 1300 nm to 1323 nm. In addition, the toxicity of Ag2Se QDs is remarkably negligible. Our work promotes the development of environment-friendly near-infrared lasers to practical lasers.
Substrate evaporation drives collective construction in termites
Authors: Facchini G. , Rathery A. , Douady S. , Sillam-Dussès D. , Perna A.
Published: October 2023

Termites build complex nests which are an impressive example of self-organization. We know that the coordinated actions involved in the construction of these nests by multiple individuals are primarily mediated by signals and cues embedded in the structure of the nest itself. However, to date there is still no scientific consensus about the nature of the stimuli that guide termite construction, and how they are sensed by termites. In order to address these questions, we studied the early building behavior of
Coptotermes gestroi
termites in artificial arenas, decorated with topographic cues to stimulate construction. Pellet collections were evenly distributed across the experimental setup, compatible with a collection mechanism that is not affected by local topography, but only by the distribution of termite occupancy (termites pick pellets at the positions where they are). Conversely, pellet depositions were concentrated at locations of high surface curvature and at the boundaries between different types of substrate. The single feature shared by all pellet deposition regions was that they correspond to local maxima in the evaporation flux. We can show analytically and we confirm experimentally that evaporation flux is directly proportional to the local curvature of nest surfaces. Taken together, our results indicate that surface curvature is sufficient to organize termite building activity, and that termites likely sense curvature indirectly through substrate evaporation. Our findings reconcile the apparently discordant results of previous studies.
Warming and altered precipitation independently and interactively suppress alpine soil microbial growth in a decadal-long experiment
Authors: Ruan Yang , Ling Ning , Jiang Shengjing , Jing Xin , He Jin-Sheng , Shen Qirong , Nan Zhibiao
Published: October 2023

Warming and precipitation anomalies affect terrestrial carbon balance partly through altering microbial growth and death in soil. However, little is known about how such eco-physiological traits responds to simultaneous regime shifts in temperature and precipitation. We used the
18
O-water quantitative stable isotope probing approach to estimate bacterial growth in alpine meadow soils of the Tibetan Plateau after a decade of warming and altered precipitation manipulation
in situ
. Our results showed that the growth of major taxa was suppressed by either individual or interactive global change factors, eliciting 40-90% of growth reduction of whole community. The antagonistic interactions of warming and altered precipitation on population growth were common (∼70% taxa), represented by the weak antagonistic interactions of warming and drought, and the neutralizing effects of warming and wet. These results are important to understand and predict the soil microbial dynamics in alpine meadow ecosystems suffering from multiple climate change factors.
Direct observation of the neural computations underlying a single decision
Authors: Steinemann Natalie A , Stine Gabriel M , Trautmann Eric M , Zylberberg Ariel , Wolpert Daniel M , Shadlen Michael N
Published: October 2023

Neurobiological investigations of perceptual decision-making have furnished the first glimpse of a flexible cognitive process at the level of single neurons (

Shadlen and Newsome, 1996

;

Shadlen and Kiani, 2013

). Neurons in the parietal and prefrontal cortex (

Kim and Shadlen, 1999

;

Romo et al., 2004

;

Hernández et al., 2002

;

Ding and Gold, 2012

) are thought to represent the accumulation of noisy evidence, acquired over time, leading to a decision. Neural recordings averaged over many decisions have provided support for the deterministic rise in activity to a termination bound (

Roitman and Shadlen, 2002

). Critically, it is the unobserved stochastic component that is thought to confer variability in both choice and decision time (

Gold and Shadlen, 2007

). Here, we elucidate this drift-diffusion-like signal on individual decisions by recording simultaneously from hundreds of neurons in the lateral intraparietal cortex (LIP). We show that a single scalar quantity derived from the weighted sum of the population activity represents a combination of deterministic drift and stochastic diffusion. Moreover, we provide direct support for the hypothesis that this drift-diffusion signal is the quantity responsible for the variability in choice and reaction times. The population-derived signals rely on a small subset of neurons with response fields that overlap the choice targets. These neurons represent the integral of noisy evidence from direction-selective neurons within LIP itself. This parsimonious architecture would escape detection by state-space analyses, absent a clear hypothesis.
Repurposing the mammalian RNA-binding protein Musashi-1 as an allosteric translation repressor in bacteria
Authors: Dolcemascolo Roswitha , Heras-Hernández María , Goiriz Lucas , Montagud-Martínez Roser , Requena-Menéndez Alejandro , Ruiz Raúl , Pérez-Ràfols Anna , Higuera-Rodríguez R. Anahí , Pérez-Ropero Guillermo , Vranken Wim F. , Martelli Tommaso , Kaiser Wolfgang , Buijs Jos , Rodrigo Guillermo
Published: October 2023

The RNA recognition motif (RRM) is the most common RNA-binding protein domain identified in nature. However, RRM-containing proteins are only prevalent in eukaryotic phyla, in which they play central regulatory roles. Here, we engineered an orthogonal post-transcriptional control system of gene expression in the bacterium
Escherichia coli
with the mammalian RNA-binding protein Musashi-1, which is a stem cell marker with neurodevelopmental role that contains two canonical RRMs. In the circuit, Musashi-1 is regulated transcriptionally and works as an allosteric translation repressor thanks to a specific interaction with the N-terminal coding region of a messenger RNA and its structural plasticity to respond to fatty acids. We fully characterized the genetic system at the population and single-cell levels showing a significant fold change in reporter expression, and the underlying molecular mechanism by assessing the
in vitro
binding kinetics and
in vivo
functionality of a series of RNA mutants. The dynamic response of the system was well recapitulated by a bottom-up mathematical model. Moreover, we applied the post-transcriptional mechanism engineered with Musashi-1 to specifically regulate a gene within an operon, to implement combinatorial regulation, and to reduce protein expression noise. This work illustrates how RRM-based regulation can be adapted to simple organisms, thereby adding a new regulatory layer in prokaryotes for translation control.
Inhibition of the serine protease HtrA1 by SerpinE2 suggests an extracellular proteolytic pathway in the control of neural crest migration
Authors: Pera Edgar M , Nilsson-De Moura Josefine , Pomeshchik Yuriy , Roybon Laurent , Milas Ivana
Published: October 2023

We previously showed that SerpinE2 and the serine protease HtrA1 modulate fibroblast growth factor (FGF) signaling in germ layer specification and head-to-tail development of Xenopus embryos. Here, we present an extracellular proteolytic mechanism involving this serpin-protease system in the developing neural crest (NC). Knockdown of SerpinE2 by injected antisense morpholino oligonucleotides did not affect the specification of NC progenitors but instead inhibited the migration of NC cells, causing defects in dorsal fin, melanocyte, and craniofacial cartilage formation. Similarly, overexpression of the HtrA1 protease impaired NC cell migration and the formation of NC-derived structures. The phenotype of SerpinE2 knockdown was overcome by concomitant downregulation of HtrA1, indicating that SerpinE2 stimulates NC migration by inhibiting endogenous HtrA1 activity. SerpinE2 binds to HtrA1, and the HtrA1 protease triggers degradation of the cell surface proteoglycan Syndecan-4 (Sdc4). Microinjection of Sdc4 mRNA partially rescued NC migration defects induced by both HtrA1 upregulation and SerpinE2 downregulation. These epistatic experiments suggest a proteolytic pathway by a double inhibition mechanism:

SerpinE2 ┤HtrA1 protease ┤Syndecan-4 → NC cell migration.
Nothing wrong with me
Authors: Brixius-Anderko Simone
Published: October 2023

An assistant professor and group leader explains how being diagnosed with autism in her early 40s changed her approach to being a scientist.
A deep learning based ensemble approach for protein allergen classification
Authors: Kumar Arun , Rana Prashant Singh
Published: October 2023

In recent years, the increased population has led to an increase in the demand for various industrially processed edibles and other consumable products. These industries regularly alter the proteins found in raw materials to generate more commercially viable end-products in order to keep up with consumer demand. These modifications result in a substance that may cause allergic reactions in consumers, thereby creating a protein allergen. The detection of such proteins in various substances is essential for the prevention, diagnosis and treatment of allergic conditions. Bioinformatics and computational methods can be used to analyze the information contained in amino-acid sequences to detect possible allergens. The article presents a deep learning based ensemble approach to identify protein allergens using Extra Tree, Deep Belief Network (DBN), and CatBoost models. The proposed ensemble model achieves higher detection accuracy by combining the prediction results of the three models using majority voting. The evaluation of the proposed model was carried out on the benchmark protein allergen dataset, and the performance analysis revealed that the proposed model outperforms the other state-of-the-art literature techniques with a protein allergen detection accuracy of 89.16%.
Heart disease severity level identification system on Hyperledger consortium network
Authors: R. Sasikumar , P. Karthikeyan
Published: October 2023

Electronic Health Records (EHRs) play a vital role in the healthcare domain for the patient survival system. They can include detailed information such as medical histories, medications, allergies, immunizations, vital signs, and more. It can help to reduce medical errors, improve patient safety, and increase efficiency in healthcare delivery. EHR approaches are proven to be an efficient and successful way of sharing patients’ personal health information. These kinds of highly sensitive information are vulnerable to privacy and security associated threats. As a result, new solutions must develop to meet the privacy and security concerns in health information systems. Blockchain technology has the potential to revolutionize the way electronic health records (EHRs) are stored, accessed, and utilized by healthcare providers. By utilizing a distributed ledger, blockchain technology can help ensure that data is immutable and secure from tampering. In this article, a Hyperledger consortium network has been developed for sharing health records with enhanced privacy and security. The attribute based access control (ABAC) mechanism is used for controlling access to electronic health records. The use of ABAC on the network provides EHRs with an extra layer of security and control, ensuring that only authorized users have access to sensitive data. By using attributes such as user identity, role, and health condition, it is possible to precisely control access to records on blockchain. Besides, a Gaussian naïve Bayes algorithm has been integrated with this consortium network for prediction of cardiovascular disease. The prediction of cardiovascular is difficult due to its correlated risk factors. This system is beneficial for both patients and physicians as it allows physicians to quickly identify high-risk patients and easily provide them with patient severity level using feature weight prediction algorithms. Dynamic emergency access control privileges are used for the emergency team and will be withdrawn once the emergency has been resolved, depending on the severity score. The system is implemented with the following medical datasets: the heart disease dataset, the Pima Indian diabetes dataset, the stroke prediction dataset, and the body fat prediction dataset. The above datasets are obtained from the Kaggle repository. This system evaluates system performance by simulating various operations using the Hyperledger Caliper benchmarking tool. The performance metrics such as latency, transaction rate, resource utilization, etc. are measured and compared with the benchmark.
Diurnal predators of restocked lab-reared and wild Diadema antillarum near artificial reefs in Saba
Authors: de Breuyn Mareike , van der Last Alex J. , Klokman Oliver J. , Hylkema Alwin
Published: October 2023

The long-spined sea urchin Diadema antillarum controls reef dynamics by grazing on algae and increasing coral recruitment. Populations of Diadema never recovered after a mass-die off in 1983 and 1984, and numbers were further reduced by a more recent die-off in 2022. To restore grazing pressure and thereby the resilience of Caribbean coral reefs, multiple Diadema restocking efforts have been performed. Although results vary, relatively low retention is one of the reasons restocking is not considered more often. If causes for the low retention can be identified, suitable measures may be able to increase restocking success. In this study, we monitored restocked lab-reared and wild juvenile Diadema on artificial reefs around Saba, Caribbean Netherlands. To assess the retention of Diadema over time, we conducted diver surveys and used underwater photo time lapse during daylight. Retention of uncaged lab-reared and wild Diadema decreased steadily with less than 30% surviving after 10 days. In total, 138 predator-prey interactions were recorded, of which 99% involved the queen triggerfish Balistes vetula, although other potential predators were present in the area. None of the recorded predator-prey interactions was successful, which suggests that artificial reefs with incorporated shelters may be suitable for juveniles as daytime refuge. However, Diadema that were more often attacked during the day were more likely to be absent the next morning. Because queen triggerfish often visited the experimental site in the first or last hour of daylight, it could be that they were more successful in their attacks when it was too dark to see anything on the photos and when Diadema came out to feed or to look for better shelter opportunities. If Diadema migrated off the artificial reef, they were probably predated during the process, because no Diadema were found on surrounding reefs. Wild Diadema were attacked significantly more often than lab-reared Diadema, possibly because the wild urchins were larger, but this did not significantly affect retention. Future restocking should be performed on natural or artificial reefs with deeper shelters, so Diadema can retract farther into their crevice, and should include night-time monitoring to identify the remaining unknown factors that cause low retention, including migration and nocturnal predation. This knowledge is urgently needed to coral reef managers so they can increase Diadema restocking success by selecting reefs with a lower predator density, protect urchins during an acclimatization period and/or conduct temporary predator control measures.
Comunidad y ayuda mutua como estrategias de crecimiento habitacional sustentable en una zona bajo pobreza energética : el caso de la población Norte Grande en el barrio Las Ánimas, Valdivia
Authors:   , Pacheco Alarcón José Pablo
Published: October 2023

El año 2014 el Ministerio del Medio Ambiente declara zona saturada por contaminación del aire a la ciudad de Valdivia. Esto se explica principalmente porque las viviendas son ineficientes desde el punto de vista térmico, generando un consumo excesivo de leña para calefaccionar los hogares. A pesar de este gasto y consumo, no se llega a niveles de confort adecuados, lo que se traduce en un constante estado de pobreza energética. Este uso masivo de biomasa como combustible deja al descubierto la situación de la vivienda social valdiviana y la heterogeneidad constructiva en que se encuentran las construcciones en general, debido a la mala calidad de la envolvente térmica. Uno de los motivos de esto es que las familias están optando por ampliar sus viviendas de forma irregular para satisfacer sus necesidades espaciales y constructivas sobre las térmicas en la vivienda generando más problemas que soluciones. Estas ampliaciones comúnmente implican a las viviendas contiguas lo que conlleva a acuerdos entre las partes dejando de lado cualquier instancia de resolución legal. A pesar de lo irregular de la situación, estos acuerdos parten de una base robusta de relación vecinal existente a nivel de barrio que se traduce tanto a nivel residencial como comunitario asociado a programas y actividades sociales que buscan mantener y aumentar el carácter relacional urbano. Si bien se han creado subsidios para el mejoramiento de viviendas, falta considerar estrategias residenciales que impliquen no solo mejoras a nivel de vivienda, sino también un incentivo a las relaciones comunitarias, el cooperativismo y las actividades sociales y productivas que involucren soluciones a nivel integral. En este sentido se estudiará el barrio las Ánimas y específicamente la población Norte Grande considerando el potencial social existente con la intención de entender tanto las necesidades de los residentes como la situación de la vivienda social y el contexto a nivel de comunidad (actividades y programas existentes) para proponer un modelo de vivienda colectiva bajo régimen de cooperativa que incorpore tanto soluciones a nivel de diseño eficiente como de integración social para un desarrollo habitacional sustentable que sirva como modelo replicable en futuros proyectos de vivienda
Arquitecturas confinadas : inseguridad, miedo urbano y copropiedad inmobiliaria en Chile
Authors:   , Torres Candia Ignacio
Published: October 2023

La investigación propone discutir la correlación entre confinamiento, inseguridad y producción comunitaria como materias históricamente cruzadas en nuestros modos de habitar y concebir la construcción de ciudades. Para esto se estudia en paralelo, la conformación de condominios cerrados de clase media en Chile, las operaciones descritas en la tratadística militar que condujeron la fundación de ciudades fortificadas a comienzos del siglo XV y algunas corrientes de diseño y planificación en contra de la inseguridad surgidas desde la segunda mitad del siglo XX. A partir de la comprensión teórica de algunos de los procedimientos de segregación que organizaron Santiago desde dictadura, se pretende vislumbrar aquellas variables arquitectónicas y urbanas que aún conducen el reconocimiento y la exclusión del «otro» en la ciudad. La figura del «confinamiento» aparece en este contexto como aquella intervención capaz de articular formalmente la relación disyuntiva entre un interior refugiado y un exterior aparentemente ofensivo e inseguro. La legitimación de este procedimiento a través de la Ley de Condominios 19.537 en el año 1997 y su correspondiente actualización tramitada desde el 2017, emerge como objeto de interés para profundizar sobre su alta eficiencia y operatividad en un contexto globalizado y neoliberal. En este sentido, el condominio organiza un perfil de defensa muy diferenciado al de la ciudad tratadística y que, sin embargo, hace perdurar al perímetro delimitador como remanente de un modelo militarista no menos violento, pero cada vez más silencioso e inmaterializado. La apertura de un espacio de proyecto localizado entre las distintas maneras de «arquitecturizar» y subvertir el confinamiento a través de la historia, ofrece la amplitud suficiente para repensar, desde la disciplina, en nuevas prácticas espaciales orientadas a la seguridad de la ciudad que requieran una reflexión crítica de sus procesos de construcción de comunidad, territorialidad y democracia.
Proyectos de viviendas Ds19: salud - cuerpo - bienestar
Authors:   , López Urqueta Patricia Carolina
Published: October 2023

La salud y el bienestar de las personas se relaciona directamente con la calidad de vida, y esta tiene una influencia directa en la felicidad de cada individuo, un estudio revelo que el 42% de la felicidad está sujeta a la calidad de la vivienda (Inmobiliaria FG, 2021). La presente investigación se centra en entender el problema actual que tienen las viviendas que clasifican dentro del estándar de Ds19 en Chile, (1) estas no logran asegurar el bienestar térmico de sus habitantes, (2) algunas constructoras e inmobiliarias tienen como respuesta a la alta demanda de estos proyectos una estrategia denominada “construcción masiva”, reutilizando un mismo diseño arquitectónico en distintas orientaciones y zonas climáticas, (3) las soluciones constructivas de envolvente tienen un performance deficiente, con esto se genera una baja calidad de vida de las personas que habitan en estas viviendas, aumentando la demanda energética sin lograr tener buenos niveles de confort interior. El objetivo de este trabajo fue evaluar 3 proyectos de vivienda social Ds19, ubicados en 3 zonas térmicas y climáticas distintas (Tabla 1), de esta manera poder comprender el performance de las viviendas en “construcción masiva”, estudiando el efecto en la demanda de calefacción, refrigeración según la ubicación y orientación, viendo el efecto en los niveles de confort térmico y calidad de vida de las personas. Estudiando diversas soluciones técnicas y arquitectónicas para poder desarrollar conocimientos y definir estrategias de implementación de procedimientos para mejorar los niveles de confort en los proyectos según la condición que requieren en su Zona Térmica y Climática. Para éste propósito se utilizó un programa de simulación de energía de edificios, Design Builder, entregando como primeros resultados, los cuales en las primeras iteraciones mostro que los proyectos, específicamente el de la Región Metropolitana y la Región de Atacama presentan desequilibrios térmicos y muchas horas fuera de los rangos de confort, por ello se propone la modificación de la orientación de las ventanas, utilización de protecciones solares, unificación del sistema de fachada (ambos tienen distintos sistemas de fachada en el primer y segundo piso), de esta manera se registró una mejora en ambos casos de hasta 5% y 6% en cantidad de horas dentro de los rangos de confort, es evidente que sólo estas propuestas no son la solución a la problemática, por ello, posteriormente se cambiara la composición de fachada para mejorar la transmitancia térmica del proyecto.
¿En cuántas casas has vivido?: vivienda social de alquiler sustentable en Chile
Authors:   ,   Pontificia Universidad Católica de Chile. Escuela de Arquitectura, Haberland Cánaves Javier Ignacio
Published: October 2023

La construcción convencional sigue un modelo de producción no sostenible. La Economía Circular propone un modelo productivo basado en el rendimiento de los recursos. La estrategia de cambiar a sistemas centrados en la mantención de los productos en lugar de su titularidad abre un espacio para la reutilización de estos. Con el cambio de paradigma de la diversificación de los modelos de vivienda en Chile surgen nuevos actores responsables del seguimiento de las condiciones físicas de los edificios, favoreciendo el servicio de proveer una vivienda digna y sustentable a largo plazo. Esta tesis explora el potencial de sustentabilidad de las viviendas sociales de alquiler en Chile, en torno al edificio Justicia Social 1. Se espera como resultado develar los procesos y ciclos asociados al uso de un edificio social de alquiler para luego aproximarse a un proyecto de arquitectura que sea representativo de estos y al mismo tiempo responda a las necesidades de los usuarios de una vivienda social de alquiler en el marco de la Economía Circular.
Cuna y aldea: espacios para una maternidad de los cuidados expandidos
Authors:   , Martínez Collarte Montserrat Begoña
Published: October 2023

La siguiente investigación se inscribe dentro del marco del taller titulado “Políticas del cuidado: Cuerpo, espacio y derechos humanos” dirigido por Gonzalo Carrasco y Alejandro Beals. Esta se presenta como las fundaciones que dan lugar a las decisiones y maneras de abordar el proyecto final, el cual consiste en un centro de maternidad ubicado en Alto Hospicio. El diseño de este centro se enfoca principalmente en las necesidades de la madre y el bebé, en contraposición a los espacios de la maternidad contemporáneos de occidente que se rigen bajo las lógicas hospitalarias modernas, es decir, espacios donde se prioriza la búsqueda de eficiencia y funcionalidad. Actualmente, en los paritorios hospitalarios se suelen dejar en un segundo plano las necesidades fisiológicas de la madre dificultando el proceso de parto y obteniendo como consecuencia graves problemas de salud mental y física debido a las prácticas de violencia obstétrica que se producen en su interior. Así, la tipología espacial de estos recintos suscita que la vulneración de los derechos de las mujeres, en un proceso tan importante como lo es la reproducción de vidas, sea un hecho cotidiano y normalizado. En la búsqueda de detectar las operaciones arquitectónicas que logran acoger las necesidades de cuidado, respeto y apoyo mutuo durante las distintas etapas de la maternidad, es decir, los procesos de gestación, parto y postparto, inicialmente se realiza un estudio de los recintos destinados al alumbramiento desde las primeras civilizaciones humanas de occidente hasta la actualidad. Luego, se realiza un análisis de algunos proyectos contemporáneos de la arquitectura de maternidades que no se rigen bajo las lógicas hospitalarias donde se hace presente una nueva tipología de espacios destinados para las mujeres gestantes en situación de vulnerabilidad llamados “hogares para la espera de la maternidad”. Por último, se exploran otros tipos de sociedades que no han logrado ser dominadas por las lógicas capitalistas y patriarcales para, así, dar con las estrategias espaciales de estas viviendas, las cuales permiten y estimulan el desarrollo en conjunto y en comunidad de los procesos de puerperio y crianza, logrando generar una red de interdependencia e interconexión.
Comportamiento higroscópico de la tierra cruda frente programas arquitectónicos y oscilación térmica en climas desérticos: análisis de sistemas constructivos, clima desértico y cargas internas mediante simulaciones de modelos virtuales
Authors:   , Caris Fuentes Christian
Published: October 2023

La tierra cruda como material de construcción ha estado presente desde las primeras civilizaciones de la humanidad y ha desarrollado numerosas técnicas constructivas que aprovechan las distintas fortalezas que la tierra posee. Entre ellas están las propiedades mecánicas y físicas como las propiedades higroscópicas o su capacidad para captar vapor de agua y liberarlo al ambiente respondiendo a las condiciones climáticas. Las condiciones climáticas, al igual que las cargas internas de uso son cruciales para determinar la eficiencia de una envolvente y su capacidad para estabilizar niveles higrotérmicos al interior del recinto construido. La envolvente, por lo tanto protege de las inclemencias del clima desértico, pero también se hace cargo de la saturación de vapor de agua en el aire mediante la respiración del material, absorbiendo agua durante el día y exhalando durante la noche el vapor de agua captado debido a la oscilación térmica. Es así como la investigación centra su estudio en la interación de estos elementos en un análisis que busca esclarecer las relaciones entre las condiciones higrotérmicas interiores y las cualidades higroscópicas del material de la envolvente. Para ello se proponen una serie de prototipos de envolventes que se someten a simulaciones en programas de análisis computacionales, con el fin de entender el material desde la relación más elemental con el clima, hasta las más complejas que incluyen cargas y horarios de uso. Se finaliza el la investigación con un prototipo que maximiza la superficie de contacto del muro interior y así poder generar un contraste de resultados a modo de converger todos los conocimientos adquiridos a lo largo del proceso investigativo y así tener una aproximación de diseño que se adecúe a las condiciones climáticas del desierto para lograr un mejor desempeño energético y de confort en el Norte de Chile.
Estructuras de entrepiso para un edificio de mediana altura en madera: construcción de un programa mixto en Talca
Authors:   , Lemus Fernández Agustín
Published: October 2023

La madera como material constructivo ha tenido alcances que han significado el desarrollo de distintas soluciones y componentes que puedan ajustarse a distintos tipos de proyectos sin comprometer la rigidez estructural del edificio. Bajo esta perspectiva, la presente investigación tratará sobre la evaluación de diferentes configuraciones para el diafragma de piso utilizando distintos componentes en madera - CLT, MLE y madera aserrada - para la construcción de un edificio de mediana altura en la ciudad de Talca, donde se busca dar respuesta a una necesidad de densificación bajo una perspectiva de sostenibilidad. Para ello se evalúan las exigencias a las que constructivamente está sometida una estructura determinada, y sobre esa base poder ajustarse con el fin de ofrecer una alternativa más eficiente para proyectos en madera.
Obsolescencias reprogramadas: sistemas de extracción, demolición y repetición como operaciones para la reprogramación de infraestructuras obsoletas
Authors:   , Torres Castro Daniel Hernán
Published: October 2023

La finalidad principal de esta tesis es analizar, describir e interpretar el edificio de estacionamientos como un objeto arquitectónico, considerando sus implicancias técnicas y comparándolas con las condiciones actuales de activación programática. A través del proyecto, se busca demostrar que la arquitectura puede tener efectos positivos en el diseño de esta tipología tan rígida como es la infraestructura de transporte. Para abordar esta problemática, se utilizará una herramienta metodológica en forma de matriz de análisis comparativo, que permitirá profundizar en el análisis y encontrar posibles soluciones. Finalmente, se llevarán a cabo una serie de operaciones proyectuales sobre 5 casos con el objetivo de demostrar que el edificio de estacionamiento puede ser considerado como una infraestructura de mediación.
Desarrollo de sistema estructural resiliente para un edificio de madera en Talca: análisis e integración vertical de industria PYME maderera de la Región del Maule
Authors:   , Daher Jerez Sebastián
Published: October 2023

El cambio climático hoy en día obliga a modificar radicalmente los paradigmas bajo los cuales las personas viven en sociedad. Desde el punto de vista de la Arquitectura, es sustancial la posibilidad de aporte al combate de este fenómeno. Es más, de acuerdo con el Informe para el Calentamiento Global de la ONU de 2019, el sector de la construcción tiene una participación del orden del 40% en las emisiones de Gases de efecto invernadero a nivel mundial (GEI). (Dubois Antonio, 2019). A partir de la premisa anterior, el presente texto trata acerca del proceso de diseño de un nuevo Distrito de Innovación Sustentable para la ciudad de Talca, construido íntegramente en madera. En el marco del lugar de emplazamiento del proyecto, se expondrá un estudio sustantivo respecto a la sostenibilidad económica, social y ambiental detrás de la industria PYME maderera de la Región del Maule. Con los datos obtenidos de dicha investigación, se ahondará en el diseño un edificio en particular dentro de este distrito, desarrollando un sistema estructural a partir de un módulo industrializado elaborado íntegramente utilizando madera local. De forma sustentable y resiliente, se propone este sistema con el objetivo de unificar y/o asociar la fuerza de trabajo de las actualmente atomizadas unidades de aserraderos de la región. Lo anterior se realizará por medio del diseño de un nuevo producto (conformado con subproductos que actualmente ofrece la región), que haga ingresar a este disgregado y disminuido mercado a una nueva escala de negocio, cohesionándolo e integrándolo verticalmente, promoviendo así un progreso social óptimo para la comunidad local de la región del Maule.