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1.
PLoS One ; 15(3): e0229645, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32119705

RESUMO

Solid-state drives (SSDs) that do not have internal dynamic random-access memory (DRAM) are being widely spread for client SSD and embedded SSD markets in recent years because they are cheap and consume less power. Obviously, their performance is lower than conventional SSDs because they cannot exploit advantages of DRAM in the controller. However, this problem can be alleviated by using host memory buffer (HMB) feature of Non-Volatile Memory Express (NVMe), which allows SSDs to utilize the DRAM of host. In this paper, we show that commercial DRAM-less SSDs clearly exhibit worse I/O performance than SSDs with internal DRAM, but this can be improved by using the HMB feature. We also present methods that reveal how the host memory buffer is used in commercial DRAM-less SSDs to improve I/O performance. Through extensive experiments, we conclude that DRAM-less SSDs evaluated in this study mainly exploit the host memory buffer as an address mapping table cache rather than a read cache or write buffer to improve I/O performance.


Assuntos
Periféricos de Computador/tendências , Dispositivos de Armazenamento em Computador/tendências , Computadores/tendências , Algoritmos , Periféricos de Computador/economia , Periféricos de Computador/estatística & dados numéricos , Dispositivos de Armazenamento em Computador/estatística & dados numéricos
2.
J Phys Chem Lett ; 10(24): 7745-7752, 2019 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-31773960

RESUMO

Logic gate functions built with nonvolatile resistive switching and thermoresponsive memory based on biologic proteins were investigated. The "NAND" and "NOR" functions of logic gates in soya protein devices have been built at room temperature by their nonvolatile ternary WORM resistive switching behaviors. Furthermore, heating the devices from room temperature to 358 K results in a switch from tristable state to bistable state WORM resistive switching behavior, indicating that the thermoresponsiveness can be efficiently memorized. The biologic transient nonvolatile memory device consisting of soya protein is illustrated. This device exhibits a long data retention time (104 s) and significant HRS/LRS ratio (∼105); the transient response of the current to voltage of an as-fabricated device is also explored. The soya protein based memory device on a gelatin film substrate is also assessed to validate the feasibility of degradation and biological compatibility for the implantable biological electronic device, that is, innoxious and avirulent to the human body. This can offer alternative avenues for exploring prospective bioelectronic devices.


Assuntos
Dispositivos de Armazenamento em Computador , Desenho de Equipamento/instrumentação , Proteínas de Plantas/química , Soja/química , Condutividade Elétrica , Eletrodos , Gelatina/química , Temperatura
3.
Gigascience ; 8(10)2019 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-31648300

RESUMO

BACKGROUND: Gene homology type classification is required for many types of genome analyses, including comparative genomics, phylogenetics, and protein function annotation. Consequently, a large variety of tools have been developed to perform homology classification across genomes of different species. However, when applied to large genomic data sets, these tools require high memory and CPU usage, typically available only in computational clusters. FINDINGS: Here we present a new graph-based orthology analysis tool, SwiftOrtho, which is optimized for speed and memory usage when applied to large-scale data. SwiftOrtho uses long k-mers to speed up homology search, while using a reduced amino acid alphabet and spaced seeds to compensate for the loss of sensitivity due to long k-mers. In addition, it uses an affinity propagation algorithm to reduce the memory usage when clustering large-scale orthology relationships into orthologous groups. In our tests, SwiftOrtho was the only tool that completed orthology analysis of proteins from 1,760 bacterial genomes on a computer with only 4 GB RAM. Using various standard orthology data sets, we also show that SwiftOrtho has a high accuracy. CONCLUSIONS: SwiftOrtho enables the accurate comparative genomic analyses of thousands of genomes using low-memory computers. SwiftOrtho is available at https://github.com/Rinoahu/SwiftOrtho.


Assuntos
Genômica/métodos , Algoritmos , Proteínas de Bactérias/genética , Análise por Conglomerados , Dispositivos de Armazenamento em Computador , Genoma Bacteriano
4.
Artigo em Inglês | MEDLINE | ID: mdl-31454944

RESUMO

This article explores the performance optimizations of an embedded database memory management system to ensure high responsiveness of real-time healthcare data frameworks. SQLite is a popular embedded database engine extensively used in medical and healthcare data storage systems. However, SQLite is essentially built around lightweight applications in mobile devices, and it significantly deteriorates when a large transaction is issued such as high resolution medical images or massive health dataset, which is unlikely to occur in embedded systems but is quite common in other systems. Such transactions do not fit in the in-memory buffer of SQLite, and SQLite enforces memory reclamation as they are processed. The problem is that the current SQLite buffer management scheme does not effectively manage these cases, and the naïve reclamation scheme used significantly increases the user-perceived latency. Motivated by this limitation, this paper identifies the causes of high latency during processing of a large transaction, and overcomes the limitation via proactive and coarse-grained memory cleaning in SQLite.The proposed memory reclamation scheme was implemented in SQLite 3.29, and measurement studies with a prototype implementation demonstrated that the SQLite operation latency decreases by 13% on an average and up to 17.3% with our memory reclamation scheme as compared to that of the original version.


Assuntos
Dispositivos de Armazenamento em Computador/normas , Bases de Dados Factuais/normas , Registros Eletrônicos de Saúde/normas , Análise de Falha de Equipamento/estatística & dados numéricos , Guias como Assunto , Armazenamento e Recuperação da Informação/normas , Dispositivos de Armazenamento em Computador/estatística & dados numéricos , Bases de Dados Factuais/estatística & dados numéricos , Registros Eletrônicos de Saúde/estatística & dados numéricos , Humanos , Armazenamento e Recuperação da Informação/estatística & dados numéricos
5.
Cells ; 8(5)2019 05 23.
Artigo em Inglês | MEDLINE | ID: mdl-31126166

RESUMO

As a typical biomedical detection task, nuclei detection has been widely used in human health management, disease diagnosis and other fields. However, the task of cell detection in microscopic images is still challenging because the nuclei are commonly small and dense with many overlapping nuclei in the images. In order to detect nuclei, the most important key step is to segment the cell targets accurately. Based on Mask RCNN model, we designed a multi-path dilated residual network, and realized a network structure to segment and detect dense small objects, and effectively solved the problem of information loss of small objects in deep neural network. The experimental results on two typical nuclear segmentation data sets show that our model has better recognition and segmentation capability for dense small targets.


Assuntos
Núcleo Celular , Aprendizado Profundo , Processamento de Imagem Assistida por Computador/métodos , Dispositivos de Armazenamento em Computador , Amarelo de Eosina-(YS)/química , Hematoxilina/química , Humanos , Modelos Logísticos , Microscopia de Fluorescência , Modelos Biológicos , Coloração e Rotulagem
6.
Carbohydr Polym ; 214: 213-220, 2019 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-30925991

RESUMO

Nowadays the development of natural biomaterials as promising building polymers for flexible, biodegradable, biocompatible and environmentally friendly electronic devices is of great interest. As the most common natural polymers, cellulose and its derivatives have the potential to be applied in the devices owing to the easy processing, nontoxicity and biodegradability. Here, write-once-read-many-times resistive switching devices based on biodegradable carboxymethyl cellulose-graphene oxide (CMC-GO) nanocomposite are demonstrated for the first time. The hybridization sites formed by the gelation of CMC and GO molecules contribute to the excellent memory behaviors. When compared with devices base on pure GO and CMC, the device with the Al/CMC-GO/Al/SiO2 structure exhibits brilliant write-once-read-many-times (WORM) switching characteristics such as high ON/OFF current ratio of ˜105, low switching voltage of 2.22 V, excellent stability and durability. What's more, the device shows high flexibility and good resistive switching behaviors even with soft PET substrate (Al/CMC-GO/Al/PET structure). This newly designed cellulose-graphene oxide-based polymer nanocomposites are quite cheap and easy processed for large scale manufacturing of memory devices and can further contribute to future biodegradable data storage applications such as portable stretchable displays, wearable electronics and electronic skins in the coming age of artificial intelligence.


Assuntos
Carboximetilcelulose Sódica/química , Dispositivos de Armazenamento em Computador , Equipamentos e Provisões Elétricas , Grafite/química , Nanocompostos/química , Alumínio/química , Carboximetilcelulose Sódica/síntese química , Eletrodos , Grafite/síntese química , Dióxido de Silício/química
7.
Sci Rep ; 8(1): 11160, 2018 07 24.
Artigo em Inglês | MEDLINE | ID: mdl-30042433

RESUMO

The Resistive RAM (RRAM) technology is currently in a level of maturity that calls for its integration into CMOS compatible memory arrays. This CMOS integration requires a perfect understanding of the cells performance and reliability in relation to the deposition processes used for their manufacturing. In this paper, the impact of the precursor chemistries and process conditions on the performance of HfO2 based memristive cells is studied. An extensive characterization of HfO2 based 1T1R cells, a comparison of the cell-to-cell variability, and reliability study is performed. The cells' behaviors during forming, set, and reset operations are monitored in order to relate their features to conductive filament properties and process-induced variability of the switching parameters. The modeling of the high resistance state (HRS) is performed by applying the Quantum-Point Contact model to assess the link between the deposition condition and the precursor chemistry with the resulting physical cells characteristics.


Assuntos
Dispositivos de Armazenamento em Computador , Condutividade Elétrica , Impedância Elétrica , Háfnio/análise , Háfnio/química , Óxidos/análise , Óxidos/química , Transistores Eletrônicos , Algoritmos , Carbono/análise , Carbono/química , Cristalização , Temperatura Alta , Sistemas Microeletromecânicos , Microscopia Eletrônica de Transmissão , Modelos Teóricos , Oxigênio/análise , Espectroscopia Fotoeletrônica , Difração de Raios X
8.
Radiat Prot Dosimetry ; 181(1): 30-33, 2018 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-29901765

RESUMO

The CD/DVDs used as radon (222Rn) and thoron (220Rn) detectors can provide a sufficiently sensitive and cost-efficient option for passive radiation monitoring in underground mines. This note presents results of measurements made under real environmental conditions by CD/DVDs. Comparison with conventional diffusion chambers was made and good correspondence was observed. Correlation between 222Rn and 220Rn was studied by CD/DVDs and no signs for any correlation were observed. Dedicated study in a mine gallery showed that CD/DVDs can be successfully used for the purposes of ventilation diagnostics by identifying sources of air contaminated with radon.


Assuntos
Poluentes Radioativos do Ar/análise , Poluição do Ar em Ambientes Fechados/análise , Dispositivos de Armazenamento em Computador , Física Sanitária , Mineração , Radônio/análise , CD-ROM , Humanos , Monitoramento de Radiação , Tecnologia Radiológica , Ventilação
9.
Respir Care ; 63(9): 1139-1146, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29921607

RESUMO

BACKGROUND: Remote monitoring is increasingly used in patients who receive home mechanical ventilation. The average volume assured pressure support mode is a target volume pressure preset mode that delivers a given tidal volume (VT) within a range of controlled inspiratory pressures. In a mode such as this, it is important to verify that the VT value retrieved from the ventilator SD card is accurate. METHODS: A lung model was set with C (Compliance) 0.075 L/cm H2O and RI (Inspiratory resistance)-RE (Expiratory resistance) 15-25 cm H2O/L/s (model 1) or with C 0.050 L/cm H2O and RI 6 cm H2O/L/s (model 2) and 6 cm H2O effort. Three home-care ventilators (A40, PrismaST30, and Vivo40) were set to average volume assured pressure support mode with 0.3 and 0.6 L VT each at PEEP 5 and 10 cm H2O, and were connected to the lung model with and without nonintentional leak. The reference airway pressure and flow were measured by a data logger. VT was expressed in body temperature and pressure saturated. We assessed the difference in VT between the ventilator SD card and a data logger relative to set VT and factors associated with its magnitude. RESULTS: For A40, PrismaST30, and Vivo40, the adjusted mean VT differences between the ventilator SD card and the data logger were -0.053 L (95% CI -0.067 to -0.039 L) (P < .001), -0.002 L (95%CI -0.022 to 0.019 L) (P = .86), and -0.067 L (95% CI -0.007 to 0.127 L) (P = .03), respectively. The partial Spearman correlation coefficients between the ventilator SD card and a data logger were 0.89 (P < .001), 0.59 (P < .001), and 0.78 (P < .001), respectively to the ventilators. The relative variations in measured VT from the set VT were 16.0, -12.0, and 6.7% for the ventilator SD card, and were -2.5, -7.5, and -27.2% for the data logger, respectively. The discrepancy in ventilator between SD card and data logger were influenced by PEEP for the PrismaST30 ventilator, nonintentional leak for the Vivo40 ventilator and PEEP, nonintentional leak, and underlying disease, the effect of each depending on the levels of the other factors, for the A40 ventilator. CONCLUSIONS: In the 3 home-care ventilators, the ventilator SD card underestimated VT. Factors involved in this difference differed among the ventilators.


Assuntos
Respiração com Pressão Positiva/estatística & dados numéricos , Testes de Função Respiratória/normas , Telemetria/normas , Volume de Ventilação Pulmonar , Ventiladores Mecânicos/estatística & dados numéricos , Resistência das Vias Respiratórias , Dispositivos de Armazenamento em Computador , Humanos , Pulmão/fisiopatologia , Modelos Anatômicos , Respiração com Pressão Positiva/instrumentação , Reprodutibilidade dos Testes , Testes de Função Respiratória/métodos , Telemetria/instrumentação , Telemetria/métodos
10.
PLoS One ; 13(5): e0197222, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29847576

RESUMO

In regression settings, parameter estimates will be biased when the explanatory variables are measured with error. This bias can significantly affect modeling goals. In particular, accelerated lifetime testing involves an extrapolation of the fitted model, and a small amount of bias in parameter estimates may result in a significant increase in the bias of the extrapolated predictions. Additionally, bias may arise when the stochastic component of a log regression model is assumed to be multiplicative when the actual underlying stochastic component is additive. To account for these possible sources of bias, a log regression model with measurement error and additive error is approximated by a weighted regression model which can be estimated using Iteratively Re-weighted Least Squares. Using the reduced Eyring equation in an accelerated testing setting, the model is compared to previously accepted approaches to modeling accelerated testing data with both simulations and real data.


Assuntos
Dispositivos de Armazenamento em Computador , Modelos Estatísticos , Simulação por Computador , Humanos , Umidade , Análise dos Mínimos Quadrados , Modelos Lineares , Temperatura
13.
Sci Rep ; 7(1): 17418, 2017 12 12.
Artigo em Inglês | MEDLINE | ID: mdl-29234084

RESUMO

This paper reports the first successful fabrication of an ITO/silkworm hemolymph/Al bio-memristor using silkworm hemolymph as the active layer. Experiments demonstrate that the silkworm hemolymph bio-memristor is a nonvolatile rewritable bipolar memory device with a current switching ratio exceeding 103. The state of the bio-memristor can be retained for more than 104 seconds and remains stable for at least 500 cycles. Tests of 1/f noise have shown that the resistance switching characteristics of the silkworm hemolymph bio-memristor are related to the formation and breaking of conductive filaments, which result from the migration of oxygen ions and the oxidation and reduction of metal cations in the silkworm hemolymph film. The naturally non-toxic silkworm hemolymph offers advantages for human health, environmental protection, and biocompatibility. The proposed nonvolatile rewritable bio-memristor based on silkworm hemolymph possesses great application potential.


Assuntos
Biomimética , Bombyx/metabolismo , Dispositivos de Armazenamento em Computador , Hemolinfa/metabolismo , Proteínas de Insetos/metabolismo , Animais , Bombyx/química , Impedância Elétrica , Desenho de Equipamento , Hemolinfa/química , Proteínas de Insetos/química , Teste de Materiais
14.
Sci Rep ; 7(1): 12427, 2017 09 29.
Artigo em Inglês | MEDLINE | ID: mdl-28963521

RESUMO

Resistive Switching in oxides has offered new opportunities for developing resistive random access memory (ReRAM) devices. Here we demonstrated bipolar Resistive Switching along with magnetization switching of cobalt ferrite (CFO) thin film using Al/CFO/FTO sandwich structure, which makes it a potential candidate for developing future multifunctional memory devices. The device shows good retention characteristic time (>104 seconds) and endurance performance, a good resistance ratio of high resistance state (HRS) and low resistance state (LRS) ~103. Nearly constant resistance values in LRS and HRS confirm the stability and non-volatile nature of the device. The device shows different conduction mechanisms in the HRS and LRS i.e. Schottky, Poole Frenkel and Ohmic. Magnetization of the device is also modulated by applied electric field which has been attributed to the oxygen vacancies formed/annihilated during the voltage sweep and indicates the presence of valence change mechanism (VCM) in our device. It is suggested that push/pull of oxygen ions from oxygen diffusion layer during voltage sweep is responsible for forming/rupture of oxygen vacancies conducting channels, leading to switching between LRS and HRS and for switching in magnetization in CFO thin film. Presence of VCM in our device was confirmed by X-ray Photoelectron Spectroscopy at Al/CFO interface.


Assuntos
Cobalto/química , Dispositivos de Armazenamento em Computador , Eletricidade , Compostos Férricos/química , Imãs , Óxidos/química , Desenho de Equipamento , Oxigênio/química
15.
J Forensic Sci ; 62(6): 1613-1616, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28597921

RESUMO

Detection of canines are well-known to be valuable in the location of contraband, such as explosives or narcotics. More recently, canines have been trained and utilized in the detection of concealed mass storage devices that might contain evidence of illegal activity such as child pornography. To lay the analytical foundation for this detection work, research was carried out to determine the volatile organic compounds associated with mass storage devices (MSD) that could be used by trained canines for detection. Headspace analysis of a variety of electronic devices was performed using solid phase microextraction (SPME) with gas chromatography/mass spectrometry (GC/MS). Analyses found several volatile compounds common to SIM and SD cards, as well as USB drives, including 2-propenenitrile, styrene, isophorone, hydroxycyclohexyl phenyl ketone, and 2-furanmethanol, tetrahydro. Results indicated that mass storage devices do have a characteristic odor profile making detection with minimal false alerts feasible for trained canines.


Assuntos
Dispositivos de Armazenamento em Computador , Cães/fisiologia , Olfato/fisiologia , Compostos Orgânicos Voláteis/isolamento & purificação , Animais , Crime , Estudos de Viabilidade , Cromatografia Gasosa-Espectrometria de Massas , Microextração em Fase Sólida
17.
PLoS One ; 11(12): e0168515, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27992513

RESUMO

Resistive memories are considered the most promising candidates for the next generation of non-volatile memory; however, attention has so far been limited to rewritable memory features for applications in resistive random access memories (RRAM). In this article, we provide a new insight into the applicability of resistive memories. The characteristics of non-rewritable resistive memories (NRRM) were investigated. Devices with Pt/ZnO/ITO architecture were prepared using magnetron sputtering, upon which various bipolar and unipolar resistive switching tests were performed. The results showed excellent distinction between the high resistance state (HRS) and low resistance state (LRS), with RHRS/RLRS = 5.2 × 1011 for the Pt/ZnO/ITO device with deposition time of 1 h. All samples were stable for more than 104 s, indicating that the devices have excellent applicability in NRRMs.


Assuntos
Dispositivos de Armazenamento em Computador , Membranas Artificiais , Óxido de Zinco
18.
Int J Med Inform ; 94: 31-8, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27573309

RESUMO

BACKGROUND: Implementation of the Picture Archiving and Communication System (PACS) is more challenging in developing countries than in developed countries. Given that the first PACS in Lao People's Democratic Republic (PDR) was successfully installed at the Children's Hospital of Lao PDR, we aimed to investigate whether the utilization rate of imaging tests increased after PACS implementation. METHODS: PACS was implemented at the Children's Hospital of Lao PDR in December 2014. We compared the utilization rates of imaging tests including X-ray and ultrasound examinations between the pre-PACS period (from December 2013 to November 2014) and the post-PACS period (from December 2014 to November 2015). The utilization rate was defined as the number of imaging tests divided by the number of patients per month. RESULTS: The average number of total imaging tests was 225.8/month (standard deviation [SD], 37.7) during the 1-year pre-PACS period and was 269.4/month (SD, 38.5) during the 1-year post-PACS period (P=0.0103). The utilization rate of total imaging tests significantly increased after PACS implementation (pre-PACS, 2.47%/month; post-PACS, 4.23%/month; P<0.0001). Increased utilization rates were observed for both X-rays (pre-PACS, 1.65%/month; post-PACS, 2.38%/month; P=0.0004) and ultrasound examinations (pre-PACS, 0.82%/month; post-PACS, 1.85%/month; P=0.0001). CONCLUSIONS: The implementation of PACS at the Children's Hospital of Lao PDR resulted in a significant increase in the utilization rate of imaging tests, suggesting the indirect benefit of improved quality of care. Our findings showed that the benefits of PACS can be realized even in a resource-limited country such as Lao PDR.


Assuntos
Diagnóstico por Imagem/estatística & dados numéricos , Implementação de Plano de Saúde , Processamento de Imagem Assistida por Computador/estatística & dados numéricos , Neoplasias/diagnóstico por imagem , Sistemas de Informação em Radiologia , Dispositivos de Armazenamento em Computador , Países em Desenvolvimento , Pesquisa sobre Serviços de Saúde , Humanos , Laos
19.
Nanotechnology ; 27(27): 275206, 2016 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-27242345

RESUMO

Parylene is a Food and Drug Administration (FDA)-approved material which can be safely used within the human body and it is also offers chemically inert and flexible merits. Here, we present a flexible parylene-based organic resistive random access memory (RRAM) device suitable for wearable biomedical application. The proposed device is fabricated through standard lithography and pattern processes at room temperature, exhibiting the feasibility of integration with CMOS circuits. This organic RRAM device offers a high storage window (>10(4)), superior retention ability and immunity to disturbing. In addition, brilliant mechanical and electrical stabilities of this device are demonstrated when under harsh bending (bending cycle >500, bending radius <10 mm). Finally, the underlying mechanism for resistance switching of this kind of device is discussed, and metallic conducting filament formation and annihilation related to oxidization/redox of Al and Al anions migrating in the parylene layer can be attributed to resistance switching in this device. These advantages reveal the significant potential of parylene-based flexible RRAM devices for wearable biomedical applications.


Assuntos
Dispositivos Eletrônicos Vestíveis , Engenharia Biomédica , Dispositivos de Armazenamento em Computador , Impedância Elétrica , Eletricidade , Desenho de Equipamento , Temperatura Alta , Compostos Orgânicos , Impressão , Temperatura
20.
Sci Rep ; 6: 28155, 2016 06 17.
Artigo em Inglês | MEDLINE | ID: mdl-27312225

RESUMO

With the continuous scaling of resistive random access memory (RRAM) devices, in-depth understanding of the physical mechanism and the material issues, particularly by directly studying integrated cells, become more and more important to further improve the device performances. In this work, HfO2-based integrated 1-transistor-1-resistor (1T1R) RRAM devices were processed in a standard 0.25 µm complementary-metal-oxide-semiconductor (CMOS) process line, using a batch atomic layer deposition (ALD) tool, which is particularly designed for mass production. We demonstrate a systematic study on TiN/Ti/HfO2/TiN/Si RRAM devices to correlate key material factors (nano-crystallites and carbon impurities) with the filament type resistive switching (RS) behaviours. The augmentation of the nano-crystallites density in the film increases the forming voltage of devices and its variation. Carbon residues in HfO2 films turn out to be an even more significant factor strongly impacting the RS behaviour. A relatively higher deposition temperature of 300 °C dramatically reduces the residual carbon concentration, thus leading to enhanced RS performances of devices, including lower power consumption, better endurance and higher reliability. Such thorough understanding on physical mechanism of RS and the correlation between material and device performances will facilitate the realization of high density and reliable embedded RRAM devices with low power consumption.


Assuntos
Dispositivos de Armazenamento em Computador , Desenho de Equipamento , Háfnio/química , Óxidos/química , Semicondutores , Impedância Elétrica , Temperatura Alta , Silicones/química , Titânio/química
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