University of Puerto Rico at Mayagüez
Recent publications
In this paper, we present a new optimization method to estimate the parameters and torques of an induction motor (IM). The proposed method is known as the Vortex Search Algorithm (VSA), whose performance is based on the behavior of the vortices created by stirred fluids. This algorithm was compared with other four optimization methods reported in the specialized literature (grasshopper optimization algorithm, particle swarm optimization, salp swarm algorithm and sine cosine algorithm), and its solution quality, precision, and robustness were validated using two test motors. During the tests, we analyzed the minimum error between the estimated values and the values provided by the manufacturer, as well as the global error of each method and their required processing time. The results show that the VSA is an excellent alternative to estimate the parameters of an IM, as it exhibited the best performance when compared to the other optimization methods.
Bananas (Musa spp.) are among the world’s most economically important staple food crops. The most important fungal leaf diseases of Musa spp. worldwide are caused by the Sigatoka disease complex, which comprise black Sigatoka (Pseudocercospora fijiensis), yellow Sigatoka (P. musae), and Eumusae leaf spot (P. eumusae). Considering the rapid spreading rate of black Sigatoka in Puerto Rico after its first observation in 2004, a disease survey was conducted from 2018 to 2020 to evaluate the Sigatoka disease complex on the island. Sixty-one leaf samples showing Sigatoka-like symptoms were collected throughout the island for diagnosis by molecular approaches and fungal isolation. Molecular analysis using species-specific primers for P. fijiensis, P. musae and P. eumusae detected the presence of P. fijiensis in fifty leaf samples. Thirty-eight fungal isolates were collected and identified by morphology and genomic sequencing from various nuclear genes. The analysis identified 24 isolates as P. fijiensis, while the rest of the isolates belonged to the genus Cladosporium spp. and Cladosporium-like spp. (n=5), Neocordana musae (n=2), Zasmidium spp. (n=6), and Z. musigenum (n=1). The high frequency of P. fijiensis found in leaf samples and collected isolates suggest that black Sigatoka has displaced the yellow Sigatoka (P. musae) in Puerto Rico. Accurate identification of fungal species causing foliar diseases in Musa spp. will allow the establishment of quarantine regulations and specific management approaches in Puerto Rico.
The eukaryome of mammals contains parabasalid protists that dramatically affect host immune function and health. However, the prevalence and diversity of parabasalids in wild reptiles and the consequences of captivity on these symbiotic protists are unknown. Reptiles are ectothermic, which expose their microbiomes to temperature fluctuations such as those driven by climate change. Thus, conservation efforts for threatened reptile species may benefit from understanding how shifts in temperature and captive breeding influence the microbiota, including parabasalids, to impact host fitness and disease susceptibility. Here, we surveyed intestinal parabasalids in wild reptiles from across three continents and compared these to captive animals. Reptiles harbor surprisingly few species of parabasalids compared to mammals, but these protists exhibited a flexible host range, suggesting specific adaptations to reptilian social structures and microbiota transmission. Furthermore, reptile-associated parabasalids are adapted to wide temperature ranges and survive colder temperatures significantly better than human-associated parabasalids. Colder temperatures altered the protist transcriptomes, causing increased expression of genes associated with detrimental interactions with their hosts. Our findings establish that parabasalids are widely distributed in the microbiota of both wild and captive reptiles and highlight how these protists respond to temperature fluctuations encountered in their ectothermic hosts. IMPORTANCE Environmental factors like climate change and captive breeding can impact the gut microbiota and host health. Therefore, conservation efforts for threatened species may benefit from understanding how these factors influence animal microbiomes. Parabasalid protists are members of the mammalian microbiota that can modulate the immune system and impact susceptibility to infections. However, little is known about parabasalids in reptiles. Here, we profile reptile-associated parabasalids in wild and captive reptiles and find that captivity has minimal impact on parabasalid prevalence or diversity. However, because reptiles are cold-blooded (ectothermic), their microbiotas experience wider temperature fluctuation than microbes in warm-blooded animals. To investigate whether extreme weather patterns affect parabasalid-host interactions, we analyzed the gene expression in reptile-associated parabasalids and found that temperature differences significantly alter genes associated with host health. These results expand our understanding of parabasalids in this vulnerable vertebrate group and highlight important factors to be taken into consideration for conservation efforts.
Removal of monomeric siloxanes from water via adsorption poses a significant challenge, particularly during water reclamation in closed-volume systems. In this study, both faulted and faultless variants UTD-1 pure silica zeolites with a DON-type framework were considered for the removal of monomethylsilanetriol (MMST), dimethylsilanediol (DMSD), and trimethylsilanol (TMS), in single- and multi-component fashion. The results showed that UTD-1faulted exhibited the largest adsorption capacity for TMS, with a maximum adsorption uptake of 73.1 mg g⁻¹ in the 1 to 140 mg L⁻¹ aqueous concentration range. This is 7× larger than UTD-1faultless and at least one magnitude larger than other materials such as activated carbon. The interaction of TMS with UTD-1faulted is mainly with OH groups from siloxy-related faults present in the material, and multicomponent adsorption tests showed that TMS helps to drive the uptake of other siloxanes via co-adsorption. UTD-1 is a promising material platform for developing adsorption-based strategies for removing persistent monomeric siloxanes from aqueous environments.
Animal displays (i.e. movement-based signals) often involve extreme behaviours that seem to push signallers to the limits of their abilities. If motor constraints limit display performance, signal evolution will be constrained, and displays can function as honest signals of quality. Existing approaches for measuring constraint, however, require multiple kinds of behavioural data. A method that requires only one kind could open up new research directions. We propose a conceptual model of performance under constraint, which predicts that the distribution of constrained performance will skew away from the constraint. We tested this prediction with sports data, because we know a priori that athletic performance is constrained and that athletes attempt to maximize performance. Performance consistently skewed in the predicted direction in a variety of sports. We then used statistical models based on the skew normal distribution to estimate the constraints on athletes and displaying animals while controlling for potential confounds and clustered data. We concluded that motor constraints tend to generate skewed behaviour and that skew normal models are useful tools to estimate constraints from a single axis of behavioural data. This study expands the toolkit for identifying, characterizing, and comparing performance constraints for applications in animal behaviour, physiology and sports.
The emerging world cannot ignore circular bio‐economic development for long. A study of circular bioeconomy pointers at the local level is required to expedite the outgrowth of local economies. The narrative of “for the locals, by the locals, and at the local” is pursued in the study, by recognizing the research gaps concerning local economies' growth needs and their effective penetration into the advancement of circular bio‐economies, followed by the research objectives. The first question includes what role circular bio‐economic indicators play at the micro‐level in growing local economies and, second, emphasis on what role circular bio‐economic indicators play at the micro‐level to boost local economies. Semi‐structured interviews were conducted with circular organizations in Afro‐Asian states, resulting in seven themes derived by collating semantic and latent codes: patriotism, psychological safety, sustainable leadership, intrusive thoughts, ancestral footprints, waste valorization, and developing green brand evangelists. The study and findings seek to contribute to micro‐level circular bioeconomy indicators. Theoretical ideas, practical applications, and limitations are acutely discussed, exfoliating the developed world's conventional waste and residual sustainable outcomes covered till now in the circular bioeconomy literature.
Small, low-power, and inexpensive marine depth sensors are of interest for a myriad of applications from maritime security to environmental monitoring. Recently, laser-induced graphene (LIG) piezoresistive pressure sensors have been proposed given their rapid fabrication and large dynamic range. In this work, the practicality of LIG integration into fieldable deep ocean (1 km) depth sensors in bulk is explored. Initially, a design of experiments (DOEs) approach evaluated laser engraver fabrication parameters such as line length, line width, laser speed, and laser power on resultant resistances of LIG traces. Next, uniaxial compression and thermal testing at relevant ocean pressures up to 10.3 MPa and temperatures between 0 and 25 °C evaluated the piezoresistive response of replicate sensors and determined the individual characterization of each, which is necessary. Additionally, bare LIG sensors showed larger resistance changes with temperature (ΔR ≈ 30 kΩ) than pressure (ΔR ≈ 1–15 kΩ), indicating that conformal coatings are required to both thermally insulate and electrically isolate traces from surrounding seawater. Sensors encapsulated with two dip-coated layers of 5 wt% polydimethylsiloxane (PDMS) silicone and submerged in water baths from 0 to 25 °C showed significant thermal dampening (ΔR ≈ 0.3 kΩ), indicating a path forward for the continued development of LIG/PDMS composite structures. This work presents both the promises and limitations of LIG piezoresistive depth sensors and recommends further research to validate this platform for global deployment.
In lactating dairy cows, heat stress reduces feed intake, alters the metabolism of the animal, and compromises milk production. Holstein cattle carrying the prolactin receptor gene mutation (SLICK) have been shown to have superior performance under tropical conditions by exhibiting increased milk yield compared with wild-type haired Holstein cattle (WT). Recent research indicated that SLICK cattle have greater mammary gland blood flow and lower vaginal temperatures, while maintaining prolonged voluntary exposure to direct solar radiation than their WT counterparts. Nevertheless, differences in molecular mechanisms between genotypes at the mammary gland level have been unexplored. The objective of the current study was to investigate possible differences in the mammary gland transcriptome from SLICK (n = 7) and WT (n = 6) Puerto Rican Holstein cattle. At 160 ± 3 days in milk (DIM), ultrasound guided mammary biopsies were collected from the left rear quarter of each animal and samples were snap frozen. Unstranded RNA-seq libraries were created from the frozen mammary tissue and sequenced using Illumina Novaseq 2x150bp. Quantification of expression was done by salmon [v1.9.0] using the Bos taurus (ARS UCD1.3) transcriptome database. Testing for significant differential expression (DE) was done using a pipeline consisting of the R packages tximport [v1.26.1] and edgeR [v3.40.2]. The fry method from edgeR was used to do gene set enrichment analysis (GSEA) for Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways and Gene Ontology (GO) terms. A single gene (GeneID:513329, major allergen Equ c 1 isoform X2) showed significant (B.H. adjusted P-value ≤ 0.05) differential expression. Aligning the protein sequence for this gene using the BLASTp against the non-redundant (NR) database revealed high similarity to two pheromones, salivary lipocalin 2 and salivary lipocalin-like. Both the KEGG pathway and GO term GSEA showed no statistically significant enrichment at B.H. adjusted P-value ≤ 0.05; however, using a less stringent criteria with a normal P-value ≤ 0.05, multiple relevant pathways were identified. For example, the KEGG pathway analysis revealed that the arachidonic acid metabolism pathway (bta00590) was enriched, and the tight junction function pathway (bta4530) was depleted in the SLICK Holstein samples. Among the GO analysis, genes were found to be downregulated in response to cold (GO:0009409), hair follicle development (GO:0001942), and vasoconstriction (GO:0042310), whereas positive regulation of oxytocin production (GO:0140668), and defense response to Gram-positive bacterium (GO:0050830) were upregulated. In conclusion, differences in gene expression were limited, but after enrichment interesting pathways were revealed and deserve further exploration to aid in elucidating different molecular mechanisms between SLICK and WT cattle.
  • Jan L. Diaz
    Jan L. Diaz
  • Andrés Alfonso Rosales Muñoz
    Andrés Alfonso Rosales Muñoz
  • Oscar Daniel Garzon Rivera
    Oscar Daniel Garzon Rivera
  • [...]
  • Fabio Andrade
    Fabio Andrade
  • Yuly V. Garcia
    Yuly V. Garcia
  • Omar F. Rodriguez-Martinez
    Omar F. Rodriguez-Martinez
  • Agustín A. Irizarry-Rivera
    Agustín A. Irizarry-Rivera
  • Fabio Andrade
    Fabio Andrade
  • Oscar D. Garzon
    Oscar D. Garzon
  • Luis E. Sepúlveda
    Luis E. Sepúlveda
  • Alexandre Nassif
    Alexandre Nassif
  • Carlos A. Peña
    Carlos A. Peña
Sleep is an essential human physiological need that has garnered increasing scientific attention due to the burgeoning prevalence of sleep-related disorders and their impact on public health. Among contemporary challenges, the demand for authentic sleep monitoring outside the confines of specialized laboratories, ideally within the home environment, has arisen. Addressing this, we explore the development of pragmatic approaches that facilitate implementation within domestic settings. Such approaches necessitate the deployment of streamlined, computationally efficient automated classifiers. In pursuit of a sleep stage classifier tailored for home use, this study rigorously assessed seven conventional neural network architectures prominent in deep learning (LeNet, ResNet, VGG, MLP, LSTM-CNN, LSTM, BLSTM). Leveraging sleep recordings from a cohort of 20 subjects, we elucidate that LeNet, VGG, and ResNet exhibit superior performance compared to recent advancements reported in the literature. Furthermore, a comprehensive architectural analysis was conducted, illuminating the strengths and limitations of each in the context of home-based sleep monitoring. Our findings distinctly identify LeNet as the most-amenable architecture for this purpose, with LSTM and BLSTM demonstrating relatively lesser compatibility. Ultimately, this research substantiates the feasibility of automating sleep stage classification employing lightweight neural networks, thereby accommodating scenarios with constrained computational resources. This advancement aims at revolutionizing the field of sleep monitoring, making it more accessible and reliable for individuals in their homes.
We present a new method of constructing three dimensional periodic arrays by composing a two dimensional periodic array with a sequence of shifts consisting of a cyclic group of points on an elliptic curve over a prime field \({\mathbb {F}}_p\). For every base array B with period (c, c) and every cyclic group G of order C there are \(\phi (C)\) families, each of size \(p^2\), of 3D arrays with period (c, c, C). We illustrate our method using a Legendre array as base array. The resulting 3D arrays have period (p, p, C), peak auto-correlation value \(C(p^2-1)\), and non-peak auto-correlation and cross-correlation values of the form \(kp^2-C\) where C is the order of the group and, in the general case, \(k\le 3\). We present experimental results that show that \(k\le 2\) for a certain type of cyclic group of points in \({\mathbb {F}}_p\) when \(p<1000\). Finally, we show that the linear complexity of our constructions compare favorably with other known constructions.
In the quest to unravel the mysteries of neurological diseases, comprehending the underlying mechanisms is supreme. The SH-SY5Y human neuroblastoma cell line serves as a crucial tool in this endeavor; however, the cells are known for its sensitivity and slow proliferation rates. Typically, this cell line is cultured with 10% Fetal Bovine Serum (FBS) supplement. Nu-Serum (NuS), a low-protein alternative to FBS, is promising to advance cell culture practices. Herein, we evaluated the substitution of NuS for FBS to test the hypothesis that an alternative serum supplement can aid and promote SH-SY5Y cell proliferation and differentiation. Our findings revealed that the NuS-supplemented group exhibited a notable increase in adhered cells compared to both the FBS and serum-free (SF) groups. Importantly, cell viability remained high in both sera treated groups, with the NuS-supplemented cells displaying significantly larger cell sizes compared to the SF-treated group. Furthermore, cell proliferation rates were higher in the NuS-treated group, and neuroblast-like morphology was observed earlier than FBS group. Notably, both FBS and NuS supported the differentiation of these cells into mature neurons. Our data supports NuS as an alternative for SH-SY5Y cell culture, with the potential to elevate the quality of research in the neuroscience field.
Biodiversity is vital for sustainable forest ecosystems. However, community values for forest biodiversity depend on environmental engagement, education, and awareness. The objectives of this study are to (1) assess households’ willingness to pay (WTP) for native plant and tree nursery in the Rio Hondo Community Forest (RHCF) of Puerto Rico, with the specific goal of supporting biodiversity and (2) examine the influence of environmental awareness on preferences for biodiversity improvement. Using a contingent valuation method, we find that households are willing to contribute $43/year to support biodiversity in the RHCF by planting native plants and trees, and that environmental awareness increases the support for biodiversity projects. The results suggest that outcomes of economic cost-benefit analyses can depend on environmental awareness. Hence, programs that support environmental awareness can improve economic efficiency of environmental protection projects.
Global declines in mangroves, seagrasses, and corals threaten the provisioning of ecosystem services to coastal communities. However, potential feedbacks between these ecosystems are poorly understood owing to a lack of studies exploring functional links between these frequently coupled nearshore tropical ecosystems. To better understand these links, we sampled seawater temperature, salinity, and pH in addition to particulate organic carbon, particulate organic nitrogen, and their respective stable isotope composition (δ¹³C and δ¹⁵N) monthly from July 2018 to June 2019 at sites ranging from inshore to offshore in La Parguera Natural Reserve, Puerto Rico. We observed persistent, year-round warmer, more acidic, and higher particulate organic matter seawater at the most inshore Bioluminescent Bay station compared to sites further offshore. Particulate organic carbon values ranged from a maximum of 764 mg/m³ at the most inshore station to a minimum of 53.96 mg/m³ at the most offshore station while particulate organic nitrogen ranged from 166 mg/m³ at the most inshore station to 6.39 mg/m³ at the most offshore station. Biogeochemical variability across spatial scales largely followed gradients in biological and physical controls, with limited differences between the more offshore coral reef sites and the most intense biogeochemical modification occurring in the shallowest and most nearshore stations. Limited temporal variability was observed for most parameters except for seasonal variations in temperature, salinity, and pH. Particulate organic matter stable isotope composition were slightly enriched at inshore stations and suggested a mixture of primarily marine allochthonous and autochthonous organic matter sources. The importance of heterotrophy for coral resilience to warming and acidification suggests this localized nutrition-rich albeit warmer and acidified waters in nearshore mangrove and seagrass ecosystems is an important functional link to nearshore corals with the potential to modulate coral resilience to ocean warming and acidification.
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5,861 members
Mauricio Cabrera-Rios
  • Department of Industrial Engineering
Sandra Cruz-Pol
  • Department of Electrical and Computer Engineering
Eduardo Schroder
  • Departamento de Ciencias Agroambientales
Paul Sundaram
  • Department of Mechanical Engineering
Arun Kumar
  • Departamento de Física
Call Box 9000, 00681, Mayagüez, Puerto Rico