2,828 research outputs found

    Two-step hyperparameter optimization method: Accelerating hyperparameter search by using a fraction of a training dataset

    Full text link
    Hyperparameter optimization (HPO) is an important step in machine learning (ML) model development, but common practices are archaic -- primarily relying on manual or grid searches. This is partly because adopting advanced HPO algorithms introduces added complexity to the workflow, leading to longer computation times. This poses a notable challenge to ML applications, as suboptimal hyperparameter selections curtail the potential of ML model performance, ultimately obstructing the full exploitation of ML techniques. In this article, we present a two-step HPO method as a strategic solution to curbing computational demands and wait times, gleaned from practical experiences in applied ML parameterization work. The initial phase involves a preliminary evaluation of hyperparameters on a small subset of the training dataset, followed by a re-evaluation of the top-performing candidate models post-retraining with the entire training dataset. This two-step HPO method is universally applicable across HPO search algorithms, and we argue it has attractive efficiency gains. As a case study, we present our recent application of the two-step HPO method to the development of neural network emulators for aerosol activation. Although our primary use case is a data-rich limit with many millions of samples, we also find that using up to 0.0025% of the data (a few thousand samples) in the initial step is sufficient to find optimal hyperparameter configurations from much more extensive sampling, achieving up to 135-times speedup. The benefits of this method materialize through an assessment of hyperparameters and model performance, revealing the minimal model complexity required to achieve the best performance. The assortment of top-performing models harvested from the HPO process allows us to choose a high-performing model with a low inference cost for efficient use in global climate models (GCMs)

    Studi Tingkat Pengetahuan Masyarakat Dan Keberadaan Tempat Perindukan Nyamuk Terhadap Kejadian Demam Berdarah Dengue Di Kelurahan Liliba Tahun 2021

    Get PDF
    Demam Berdarah dengue (DBD) merupakan penyakit menular yang disebabkan oleh virus dengue dan ditularkan melalui vektor nyamuk dari spesies Aedes aegypti atau Aedes albopictus (Depkes RI 1995). Kelurahan Liliba merupakan salah satu kelurahan endemis DBD di Kota Kupang dengan 7 kasus (Dinkes Provinsi NTT, 2019). Penelitian ini bertujuan untuk mengetahui gambaran tingkat pengetahuan Masyarakat dan keberadaan tempat perindukan nyamuk terhadap kejadian demam berdarah dengue di Kelurahan Liliba tahun 2021. Jenis penelitian deskriptif. Variabel penelitian tingkat pengetahuan masyarakat dan keberadaan tempat perindukan nyamuk. Populasi dalam penelitian ini 3370 KK di Kelurahan Liliba. Sampel dalam penelitian ini sebanyak 97 responden. Metode pengumpulan data primer diperoleh dengan observasi dan wawancara yang dilakukan secara langsung pada responden dengan instrument berupa kuisioner dan formulir observasi (checklist) dari masing-masing sampel yang diteliti, dihitung, dan dibandingkan dengan kriteria pencapaian setelah itu diambil kesimpulan kemudian dimasukan dalam master tabel berdasarkan variabel penelitian dan dibuat kesimpulan berupa perhitungan presentase dan dianalisa secara deskriptif. Hasil penelitian untuk tingkat pengetahuan termasuk dalam kategori kurang 48%, untuk tempat perindukan nyamuk jenis container bak mandi di dalam rumah 23%, diluar rumah78%, HI 86% dengan nilai DF9, CI 25% dengan nilai DF6, BI 196%. Disimpulkan bahwa tingkat pengetahuan masyarakat masuk dalam kategori kurang, tempat perindukan jentik nyamuk Aedes sp di dalam dan diluar rumah dapat dilihat bahwa bak mandi tempat yang paling dominan terdapat jentik Aedes sp dibandingkan dengan container yang lain. HI, CI, BI termasuk kategori kepadatan tinggi. Saran yang penulis berikan pada pihak puskesmas, pemerintah dan masyarakat seperti melakukan penyuluhan secara rutin tentang demam berdarah dengue, serta upaya yang dilakukan dalam pengendalian nyamuk DBD yaitu pengendalian secara fisik/mekanik, kimiawi, biologi dan manipulasi lingkungan

    Impact of the COVID-19 pandemic on the mental and physical health and overall wellbeing of university students in Portugal

    Get PDF
    Throughout the pandemic of COVID-19 caused by SARS-CoV-2, university students were considered a vulnerable risk group for mental health impairment and wellbeing deterioration. This study aimed at evaluating the pandemic's impact on the physical and mental health and wellbeing among students of a Portuguese university. This cross-sectional study included 913 participants and ran from June to October 2020. Data collected included sociodemographics, three mental health self-report questionnaires (Depression Anxiety Stress Scale, Eating Disorder Examination Questionnaire and Brief COPE) and lifestyle practices (eating and sleeping patterns, media, and entertainment habits) during the first months of the pandemic, which included a 72-day full national lockdown. Descriptive and correlational statistical analysis were conducted. Students' food habits changed during the pandemic, namely on the consumption of snacks and fast food and, overall, less balanced meals became more prevalent. Additionally, almost 70% of the students reported Body Mass Index changes, while 59% went through sleep pattern changes-these were more pronounced in women and younger students. Over half (67%) of the inquirees exhibited an increase in their stress, depression, and generalized anxiety symptoms. Also, the study demonstrates that students' lifestyles trended negatively during the pandemic and highlights how important regular psychological, health monitoring and emotional support is, amongst this somehow overlooked population throughout the pandemic. Universities should provide support to overcome challenges in future stressful situations. This study might have an impact on how universities and higher education systems approach their students in terms of mental and physical health monitoring and promotion in future situations, non-related with COVID. Moreover, it has a large sample of students well characterized in terms of mental and physical health, which might be of interest for future comparison with other worldwide group of students throughout stressful situations, such as tragic events, wars, pandemics.The study was funded by Universidade Catolica Portuguesa within the Interdisciplinary project 2020. This work was also supported by National Funds from FCT - Fundacao para a Ciencia e a Tecnologia through project UIDB/50016/2020. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

    The Implementation of NEMS GFS Aerosol Component (NGAC) Version 1.0 for Global Dust Forecasting at NOAA NCEP

    Get PDF
    The NOAA National Centers for Environmental Prediction (NCEP) implemented the NOAA Environmental Modeling System (NEMS) Global Forecast System (GFS) Aerosol Component (NGAC) for global dust forecasting in collaboration with NASA Goddard Space Flight Center (GSFC). NGAC Version 1.0 has been providing 5-day dust forecasts at 1deg x 1deg resolution on a global scale, once per day at 00:00 Coordinated Universal Time (UTC), since September 2012. This is the first global system capable of interactive atmosphere aerosol forecasting at NCEP. The implementation of NGAC V1.0 reflects an effective and efficient transitioning of NASA research advances to NCEP operations, paving the way for NCEP to provide global aerosol products serving a wide range of stakeholders, as well as to allow the effects of aerosols on weather forecasts and climate prediction to be considered

    Cell walls of the dimorphic fungal pathogens Sporothrix schenckii and Sporothrix brasiliensis exhibit bilaminate structures and sloughing of extensive and intact layers

    Get PDF
    This work was supported by the Fundação Carlos Chagas de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ), grants E-26/202.974/2015 and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), grants 229755/2013-5, Brazil. LMLB is a senior research fellow of CNPq and Faperj. NG acknowledged support from the Wellcome Trust (Trust (097377, 101873, 200208) and MRC Centre for Medical Mycology (MR/N006364/1). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

    Pandrug-Resistant Acinetobacter baumannii Causing Nosocomial Infections in a University Hospital, Taiwan

    Get PDF
    The rapid emergence (from 0% before 1998 to 6.5% in 2000) of pandrug-resistant Acinetobacter baumannii (PDRAB) was noted in a university hospital in Taiwan. To understand the epidemiology of these isolates, we studied 203 PDRAB isolates, taken from January 1999 to April 2000: 199 from 73 hospitalized patients treated at different clinical settings in the hospital and 4 from environmental sites in an intensive-care unit. Pulsed-field gel electrophoresis analysis and random amplified polymorphic DNA (RAPD) generated by arbitrarily primed polymerase chain reaction of these 203 isolates showed 10 closely related genotypes (10 clones). One (clone 5), belonging to pulsotype E and RAPD pattern 5, predominated (64 isolates, mostly from patients in intensive care). Increasing use of carbapenems and ciprofloxacin (selective pressure) as well as clonal dissemination might have contributed to the wide spread of PDRAB in this hospital

    State-space Manifold and Rotating Black Holes

    Full text link
    We study a class of fluctuating higher dimensional black hole configurations obtained in string theory/ MM-theory compactifications. We explore the intrinsic Riemannian geometric nature of Gaussian fluctuations arising from the Hessian of the coarse graining entropy, defined over an ensemble of brane microstates. It has been shown that the state-space geometry spanned by the set of invariant parameters is non-degenerate, regular and has a negative scalar curvature for the rotating Myers-Perry black holes, Kaluza-Klein black holes, supersymmetric AdS5AdS_5 black holes, D1D_1-D5D_5 configurations and the associated BMPV black holes. Interestingly, these solutions demonstrate that the principal components of the state-space metric tensor admit a positive definite form, while the off diagonal components do not. Furthermore, the ratio of diagonal components weakens relatively faster than the off diagonal components, and thus they swiftly come into an equilibrium statistical configuration. Novel aspects of the scaling property suggest that the brane-brane statistical pair correlation functions divulge an asymmetric nature, in comparison with the others. This approach indicates that all above configurations are effectively attractive and stable, on an arbitrary hyper-surface of the state-space manifolds. It is nevertheless noticed that there exists an intriguing relationship between non-ideal inter-brane statistical interactions and phase transitions. The ramifications thus described are consistent with the existing picture of the microscopic CFTs. We conclude with an extended discussion of the implications of this work for the physics of black holes in string theory.Comment: 44 pages, Keywords: Rotating Black Holes; State-space Geometry; Statistical Configurations, String Theory, M-Theory. PACS numbers: 04.70.-s Physics of black holes; 04.70.Bw Classical black holes; 04.70.Dy Quantum aspects of black holes, evaporation, thermodynamics; 04.50.Gh Higher-dimensional black holes, black strings, and related objects. Edited the bibliograph

    Phosphorylation of silk fibroins improves the cytocompatibility of silk fibroin derived materials: a platform for the production of tuneable material

    Get PDF
    Silk fibroin demonstrates great biocompatibility and is suitable for many biomedical applications, including tissue engineering and regenerative medicine. Current research focuses on manipulating the physico-chemical properties of fibroin, and examining the effect of this manipulation on firobin's biocompatibility. Regenerated silk fibroin was modified by in vitro enzymatic phosphorylation and cast into films. Films were produced by blending, at several ratios, the phosphorylated and un-phosphorylated fibroin solutions. Fourier transform infra-red spectroscopy was used to determine the specific P–OH vibration peak, confirming the phosphorylation of the regenerated silk fibroin solution. Differential scanning calorimetry showed that phosphorylation altered the intra- and inter-molecular interactions. Further experiments demonstrated that phosphorylation can be used to tailor the hydrophylicity/hydrophobicity ratio as well as the crystalinity of silk fibroin films. Release profiling of a model drug was highly dependent on silk modification level. Cytotoxicity assays showed that exposure to lixiviates of phosphorylated films only slightly affected cellular metabolism and proliferation, although direct contact resulted in a strong direct correlation between phosphorylation level and cell proliferation. This new method for tuning silk biomaterials to obtain specific structural and biochemical features can be adapted for a wide range of applications. Phosphorylation of silk fibroins may be applied to improve the cytocompatibility of any silk-based device that is considered to be in contact with live animals or human tissues.The authors would like to acknowledge the support granted to the authors by European NOVO Project, contract no. FP7-HEALTH 2011-two-stage 278402
    corecore