Taxonomy, valve ultrastructure, nomenclature and a comparison of two species of Bacillariales from freshwaters of Puerto Rico

Phytotaxa ◽  
2020 ◽  
Vol 468 (2) ◽  
pp. 190-202
Author(s):  
J.P. KOCIOLEK ◽  
A. DANZ ◽  
J. SWENSON ◽  
K. THIROUIN ◽  
D.M. WILLIAMS ◽  
...  
Keyword(s):  
Puerto Rico ◽  
Central Area ◽  
Ecological Monitoring ◽  
Virgin Islands ◽  
The U.S

We have investigated two canal-raphe bearing taxa from two freshwater long-term ecological monitoring sites in the NEON program from Puerto Rico. The identity of these two taxa have been misunderstood, and they have been mistaken for one another, due to being similar in size, shape and having interrupted striae across the valve face. Denticula occidentalis Østrup was described from the U.S. Virgin Islands, and like its congeners has fibulae that extend across the valve face as thickened ribs. The species also has valvocopulae that are typical for the genus, with arched sections that clasp onto the knob-like fibulae. Denticula occidentalis has a discontinuous raphe system, and external proximal raphe ends are hooked towards the valve center and elongated. Grunowia portoricensis, sp. nov. has fibulae restricted to the raphe side of the valve, though unlike most members of the genus the fibulae are knob-like. The raphe is continuous across the central area. Though described here as new to science, the species has been illustrated previously from Venezuela. Distinctions between Nitzschia, Denticula and Grunowia are discussed.

Geology and hydrogeology of the Caribbean islands aquifer system of the Commonwealth of Puerto Rico and the U.S. Virgin Islands

2002 ◽  
Author(s):  
Robert A. Renken ◽  
W. C. Ward ◽  
I.P. Gill ◽  
Fernando Gómez-Gómez ◽  
Jesús Rodríguez-Martínez ◽  
...  
Keyword(s):  
Puerto Rico ◽  
Virgin Islands ◽  
Aquifer System ◽  
Caribbean Islands ◽  
The Caribbean ◽  
The U.S

scholarly journals Analyzing the Impact of Climate Factors on GNSS-Derived Displacements by Combining the Extended Helmert Transformation and XGboost Machine Learning Algorithm

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Hanlin Liu ◽  
Linqiang Yang ◽  
Linchao Li
Keyword(s):  
Machine Learning ◽  
Puerto Rico ◽  
Reference Frame ◽  
Learning Algorithm ◽  
Virgin Islands ◽  
Machine Learning Algorithm ◽  
Climate Factors ◽  
Helmert Transformation ◽  
The Impact

A variety of climate factors influence the precision of the long-term Global Navigation Satellite System (GNSS) monitoring data. To precisely analyze the effect of different climate factors on long-term GNSS monitoring records, this study combines the extended seven-parameter Helmert transformation and a machine learning algorithm named Extreme Gradient boosting (XGboost) to establish a hybrid model. We established a local-scale reference frame called stable Puerto Rico and Virgin Islands reference frame of 2019 (PRVI19) using ten continuously operating long-term GNSS sites located in the rigid portion of the Puerto Rico and Virgin Islands (PRVI) microplate. The stability of PRVI19 is approximately 0.4 mm/year and 0.5 mm/year in the horizontal and vertical directions, respectively. The stable reference frame PRVI19 can avoid the risk of bias due to long-term plate motions when studying localized ground deformation. Furthermore, we applied the XGBoost algorithm to the postprocessed long-term GNSS records and daily climate data to train the model. We quantitatively evaluated the importance of various daily climate factors on the GNSS time series. The results show that wind is the most influential factor with a unit-less index of 0.013. Notably, we used the model with climate and GNSS records to predict the GNSS-derived displacements. The results show that the predicted displacements have a slightly lower root mean square error compared to the fitted results using spline method (prediction: 0.22 versus fitted: 0.31). It indicates that the proposed model considering the climate records has the appropriate predict results for long-term GNSS monitoring.

Trial without Jury in Guam, USA

2019 ◽  
Vol 38 (4) ◽  
pp. 811-841
Author(s):  
Katherine Unterman
Keyword(s):  
Puerto Rico ◽  
Participatory Democracy ◽  
Virgin Islands ◽  
The Philippines ◽  
American Empire ◽  
Administration Of Justice ◽  
Jury Trials ◽  
Civil Trials ◽  
Independence Movements ◽  
The U.S

This article adds to the growing literature about how the Supreme Court's decisions in the Insular Cases affected the residents of the U.S. territories. It focuses on the territory of Guam, which lacked juries in both criminal and civil trials until 1956–nearly sixty years after the island became a U.S. possession. Residents of Puerto Rico, Hawaii, and the Virgin Islands had limited jury trials, but Guam was left out due to its strategic military significance as well as racialized ideas about the capabilities of Chamorros, the native inhabitants of the island. This article recovers the struggle by Guamanians to gain jury trials. It argues that independence movements, like those in the Philippines and Puerto Rico, were not the only forms of resistance to American empire. Through petitions, court challenges, and other forms of activism, Guamanians pushed for jury trials as a way to assert local agency and engage in participatory democracy. For them, the Insular Cases were not just abstract rulings about whether the Constitution followed the flag; they deeply affected the administration of justice on the ground for ordinary Guamanians.

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