Easter Island Research Articles

Unraveling biotypes of the northern house mosquito, Culex pipiens s.l. (Diptera: Culicidae): molecular differentiation and morphometric analysis.

Geometric morphometrics was used to determine whether geographic isolation could explain differences in wing size and shape between and within continental (27°S to 41°S) and insular (Rapa Nui) populations of Culex pipiens s.s. Linnaeus and their biotypes (f. pipiens and f. molestus). Molecular protocols based on polymorphisms in the second intron of nuclear locus ace-2 (acetylcholinesterase-2) were used to differentiate Cx. pipiens s.s. from Cx. quinquefasciatus Say, and an assay based on polymorphisms in the flanking region of a microsatellite locus (CQ11) was used to identify biotypes. Culex pipiens f. molestus and hybrids shared larval habitats in all continental sites, while Cx. pipiens f. pipiens was found in 5 of the 10 sites. Only biotype molestus was found in Rapa Nui (Easter Island) Pipiens and molestus biotypes occur sympatrically in aboveground locations, and only molestus was found in the underground site (ME). Biotype molestus was dominant in rural locations and preferably anthropophilic. These results agree with the ecological descriptions previously reported for the biotypes of Cx. pipiens s.s. Procrustes ANOVA only showed differences in centroid size between biotypes in females and males and did not show significant differences in wing shape. However, we found significant differences among the geographic areas in the centroid size and wing shape of both females and males. Particularly, the population of Rapa Nui Island had shorter wings than the continental populations. The results highlight the effects of geographic and environmental processes on morphotypes in vector mosquitoes.

Path analysis model for preventing stunting in dryland area island East Nusa Tenggara Province, Indonesia.

The problem of stunting is still a fundamental problem in Indonesia's human development. East Nusa Tenggara Province is an archipelago dryland area where in 2007-2021 it has contributed to the highest number of stunting children prevalence in Indonesia. This study aims to determine the relationship of variables in individual, household and district level with the prevalence of stunting. This type of research is observational study with a cross sectional design. This study used individual secondary data from the Indonesian Nutritional Status Survey in 2021 consisting of 7,835 toddlers and National Social Economics Survey 2021. This research found that both specific & sensitive intervention programs had an influence in accelerating the decline in stunting prevalence (higher score on Z Score). Results also revealed the positive influence of the food access variable on nutritional intake. The results of the path analysis test showed that sensitive intervention program variables have a positive effect on food access variable and environmental variable (environmental sanitation) such as the habit of open defecation and healthcare. There was significant relationship on disease history, environment and intake to Height for Age (HAZ) score. In conclusion, direct and indirect factors have important roles to prevent stunting. Sensitive and specific intervention program, food access, macro determinants and environment are the indirect indicators which contribute significantly to the stunting. The risk of children under five years old experiencing malnourished nutritional status increases with a history of infectious disease (diarrhea, ARI, worms). The risk of children under five years experiencing malnourished nutritional status decreases with adequate nutritional intake. It is hoped that there will be a special model of stunting control interventions at the individual level and at the family, household and district level that are integrated and of high quality through multisectoral cooperation in the dryland areas of the islands of East Nusa Tenggara Province.

Vertical sediment distribution mechanism in tidal flats -A case study in Zhoushan Archipelago

Tidal flats connect terrestrial and oceanic environments, and play an important role in the evolution of coastal ecosystems and geomorphology. Taking tidal flat on Zhairuoshan Island (ZRS) as an example, we studied the dynamic characteristics of suspended sediment concentration (SSC), sediment resuspension, and transportation in tidal flats. The field data of the waves, currents, and sediments were obtained from the tidal flat on the east of ZRS Island. The results show that current-induced bed shear stress is dominant. Under the combined action of waves, tides, and currents, SSC has two main periods (12.2 h, 6.2 h, 60−80%) and three minor periods (23.5 h, 8.2 h, and 5.1 h, 20−40%). Advection transport is dominant, at approximately 2–3 times the sediment resuspension, and the net sediment flux is onshore. Turbulent intermittent events play an important role in sediment resuspension, and their probability is affected by velocity. The vertical instantaneous transport of sediment depends on wave height. The vertical profile of SSC shows that, at high current velocity, the sedimentation formula that considers flocculation better fits the vertical profile of suspended sediment using the Rouse formula. The settling velocity of a single particle fits better at low current velocities, indicating that the flocculation of sediment is weak at low velocities. This study improves our understanding on near-bottom sediment characteristics and controlling mechanism in tidal flat in muddy coasts.

The Long Scientific Journey of Sirolimus (Rapamycin): From the Soil of Easter Island (Rapa Nui) to Applied Research and Clinical Trials on β-Thalassemia and Other Hemoglobinopathies.

In this review article, we present the fascinating story of rapamycin (sirolimus), a drug able to induce γ-globin gene expression and increased production of fetal hemoglobin (HbF) in erythroid cells, including primary erythroid precursor cells (ErPCs) isolated from β-thalassemia patients. For this reason, rapamycin is considered of great interest for the treatment of β-thalassemia. In fact, high levels of HbF are known to be highly beneficial for β-thalassemia patients. The story of rapamycin discovery began in 1964, with METEI, the Medical Expedition to Easter Island (Rapa Nui). During this expedition, samples of the soil from different parts of the island were collected and, from this material, an antibiotic-producing microorganism (Streptomyces hygroscopicus) was identified. Rapamycin was extracted from the mycelium with organic solvents, isolated, and demonstrated to be very active as an anti-bacterial and anti-fungal agent. Later, rapamycin was demonstrated to inhibit the in vitro cell growth of tumor cell lines. More importantly, rapamycin was found to be an immunosuppressive agent applicable to prevent kidney rejection after transplantation. More recently, rapamycin was found to be a potent inducer of HbF both in vitro using ErPCs isolated from β-thalassemia patients, in vivo using experimental mice, and in patients treated with this compound. These studies were the basis for proposing clinical trials on β-thalassemia patients.

New visualization method for cranial carvings of Rapanui wooden figurines

AbstractPrecontact culture of Easter Island (Rapa Nui) produced wooden figurines carved with attention to detail and featuring careful surface polishing. These figurines depict humans and akuaku spirits. Male figurines usually have bald heads adorned with elaborate designs carved in low relief, depicting human beings, fishes, birds, chimerical creatures, or material objects of Rapanui culture. As cranial carvings swirl around the head of the figurine, it is impossible to document them fully with a single photograph. Several publications show cranial carvings in free‐hand drawing. In this study, we suggest a methodology for design unwrapping from nearly hemispherical surface, projecting it onto a plane in a uniform and replicable fashion. To do so, we employ 3D models of figurines' heads obtained with photogrammetric modeling. Although this approach features certain limitations, it permits far richer level of detail and documentation accuracy in comparison to commonly used free‐hand drawings.

A melting-pot for Pterodroma petrels on Rapa Nui: ecological divergence and reproductive isolation in a contact zone

Speciation is thought to depend on general ecological segregation rather than on strict allopatry in species with planetary-scale foraging ranges, such as Pterodroma petrels. Separation in both breeding islands and foraging grounds are generally considered to be the conditions for prezygotic isolation. However, it is unclear how both can be maintained in a context of ongoing distributional range shifts due to global change, with range contractions and expansions caused by changing land use in breeding territories and oceanographic conditions impacting productivity areas. In this context, we expect that wherever the fragile balance of allopatric segregation breaks down, gene flow may be re-established across the borders of what is currently considered separated species. In these “melting pot” areas, fine-scale ecological differentiation is likely the only force opposing panmixia in otherwise highly similar organisms. In this study, we focus on six Polynesian Pterodroma species currently found on Motu Nui, a protected islet offshore of Rapa Nui (Easter Island), four of which have likely extended their breeding range to that island recently. To understand the fine-scale interaction between these closely-related species in their new contact zone, we used an integrative approach combining ecological and genetic methods, including morphometric, bioacoustics, stable isotope niche reconstruction, breeding site characterisation, phenology traits, and both nuclear and mitochondrial DNA markers. We found that significant amounts of gene flow occur across what is currently considered species boundaries, sometimes questioning the relevance of the accepted species classification. Interestingly, our results indicate that multivariate ecological distance between individuals in a group of closely related species (P. alba, P. atrata, P. heraldica, and P. neglecta) is a relevant predictor of gene flow intensity, while more distant species such as P. ultima and P. nigripennis seem to maintain reproductive isolation. Thus, the case of Pterodroma petrels supports the idea that incomplete allopatric speciation processes may be halted or even reversed on a secondary contact zone. Beyond their direct taxonomical relevance, our results underline the importance of considering fine ecological structures for biodiversity mapping and conservation policies.

An algorithm for correction of atmospheric scattering dilution effects in volcanic gas emission measurements using skylight differential optical absorption spectroscopy

Differential Optical Absorption Spectroscopy (DOAS) is commonly used to measure gas emissions from volcanoes. DOAS instruments measure the absorption of solar ultraviolet (UV) radiation scattered in the atmosphere by sulfur dioxide (SO2) and other trace gases contained in volcanic plumes. The standard spectral retrieval methods assume that all measured light comes from behind the plume and has passed through the plume along a straight line. However, a fraction of the light that reaches the instrument may have been scattered beneath the plume and thus has passed around it. Since this component does not contain the absorption signatures of gases in the plume, it effectively “dilutes” the measurements and causes underestimation of the gas abundance in the plume. This dilution effect is small for clean-air conditions and short distances between instrument and plume. However, plume measurements made at long distance and/or in conditions with significant atmospheric aerosol, haze, or clouds may be severely affected. Thus, light dilution is regarded as a major error source in DOAS measurements of volcanic degassing. Several attempts have been made to model the phenomena and the physical mechanisms are today relatively well understood. However, these models require knowledge of the local atmospheric aerosol composition and distribution, parameters that are almost always unknown. Thus, a practical algorithm to quantitatively correct for the dilution effect is still lacking. Here, we propose such an algorithm focused specifically on SO2 measurements. The method relies on the fact that light absorption becomes non-linear for high SO2 loads, and that strong and weak SO2 absorption bands are unequally affected by the diluting signal. These differences can be used to identify when dilution is occurring. Moreover, if we assume that the spectral radiance of the diluting light is identical to the spectrum of light measured away from the plume, a measured clean air spectrum can be used to represent the dilution component. A correction can then be implemented by iteratively subtracting fractions of this clean air spectrum from the measured spectrum until the respective absorption signals on strong and weak SO2 absorption bands are consistent with a single overhead SO2 abundance. In this manner, we can quantify the magnitude of light dilution in each individual measurement spectrum as well as obtaining a dilution-corrected value for the SO2 column density along the line of sight of the instrument. This paper first presents the theory behind the method, then discusses validation experiments using a radiative transfer model, as well as applications to field data obtained under different measurement conditions at three different locations; Fagradalsfjall located on the Reykjanaes peninsula in south Island, Manam located off the northeast coast of mainland Papua New Guinea and Holuhraun located in the inland of north east Island.

An update of the distribution of the assassin bug Zelus renardii (Heteroptera: Reduviidae) in Chile, with first records from the Oceanic Easter Island

The distribution of Zelus renardii (Kolenati) in Chile is updated. The new records extend their distribution to both north and south extremes, from Arica y Parinacota to Magallanes regions. Additionally, first records are provided for the Oceanic Easter Island.

Earlier collapse of Anthropocene ecosystems driven by multiple faster and noisier drivers

A major concern for the world’s ecosystems is the possibility of collapse, where landscapes and the societies they support change abruptly. Accelerating stress levels, increasing frequencies of extreme events and strengthening intersystem connections suggest that conventional modelling approaches based on incremental changes in a single stress may provide poor estimates of the impact of climate and human activities on ecosystems. We conduct experiments on four models that simulate abrupt changes in the Chilika lagoon fishery, the Easter Island community, forest dieback and lake water quality—representing ecosystems with a range of anthropogenic interactions. Collapses occur sooner under increasing levels of primary stress but additional stresses and/or the inclusion of noise in all four models bring the collapses substantially closer to today by ~38–81%. We discuss the implications for further research and the need for humanity to be vigilant for signs that ecosystems are degrading even more rapidly than previously thought.

Preliminary study on Strait of Malacca Tide Wave Characteristic from AIS Data Mining

In this study, advanced data mining techniques and Automatic Identification System (AIS) data were used to examine the tidal and wave dynamics of the Strait of Malacca. This strait has been an important commercial route for centuries, connecting the Indian Ocean to the South China Sea and the Pacific Ocean. It is located between Sumatra Island's east coast and Peninsular Malaysia's west coast, with the Strait of Singapore at its southeast end. The study's initial findings indicate a strong correlation between the distance of ships' coordinates and the timing of the tide, which is mainly influenced by the harmonic motion of the sun and the moon. Through AIS data mining and analysis, this study demonstrates the potential for predicting sea heights during tidal events. These results could be further explored in future research. Overall, this study offers valuable insights into the intricate tidal and wave dynamics of the world's longest strait and highlights the promise of AIS data mining for advancing our knowledge of oceanic phenomena. The research outcomes could potentially facilitate the development of more precise and effective methods for forecasting sea heights and predicting other marine processes.

The Girl Who Heard the Music: How One Pianist and 85,000 Bottles and Cans Brought New Hope to an Island by Marni Fogelson (review)

Reviewed by: The Girl Who Heard the Music: How One Pianist and 85,000 Bottles and Cans Brought New Hope to an Island by Marni Fogelson April Spisak Fogelson, Marni The Girl Who Heard the Music: How One Pianist and 85,000 Bottles and Cans Brought New Hope to an Island; written by Marni Fogelson and Mahani Teave; illus. by Marta Álvarez Miguéns. Sourcebooks, 2023 [40p] Trade ed. ISBN 9781728262314 $18.99 Reviewed from digital galleys R Gr. 2-4 This picture book biography focuses on the life and activism of Mahani Teave, a talented musician who grew up on Rapa Nui (known more widely as Easter Island, a designation assigned to it by Dutch explorers in the early 1700s), left to pursue a career as a concert pianist, and ultimately returned home to help repair environmental damage to her island and begin a musical school. Frequent time jumps, heavy use of similes, and clever, enthusiastic asides all create an informal pace and tone that is accessible to young readers, and the book wisely focuses on the activism done on one island, narrowing the overwhelming global crisis of climate change down to a specific school that is a model of recycling and creative, intelligent use of natural resources. The illustrations are dreamy and bright with highlights of organic shades and flowing, peaceful lines, emphasizing the natural beauty even while there are grave concerns about, for example, the environmental damage tourists have done to the land or the shocking amount of trash in the surrounding ocean. Extensive end matter rewards the persistent reader with a wealth of information about Earthships (the type of innovative and environmentally friendly building blueprint used to construct the music school), background on the island language and culture, and a biography of Teave's life that provides further detail about the dates she studied, her musical career, and what specifically drew her back to Rapa Nui. Copyright © 2023 The Board of Trustees of the University of Illinois

A wooden hand from Easter Island (Rapa Nui), part II

A wooden hand from Easter Island (Rapa Nui), part II

Detection of the Large White butterfly Pieris brassicae (Linnaeus, 1758) (Lepidoptera, Pieridae) in Rapa Nui (Easter Island)

The Large White butterfly (Pieris brassicae (Linnaeus, 1758)) originally from the Palaearctic and previously introduced to South Africa and Chile is detected on Rapa Nui (Easter Island). The records correspond to all stages of the life cycle: eggs, caterpillars, pupa and adults. Caterpillars were found feeding on Tropaeolum majus. The introduction is likely to have occurred from mainland Chile, as the species has not been reported in French Polynesia. A dark green coloration present on the underside of the wings is congruent with the one reported from the Chilean population. The origin of colonisation still remains to be tested using molecular tools.

The Power of Their Will: Slaveholding Women in Nineteenth-Century Cuba

The Power of Their Will: Slaveholding Women in Nineteenth-Century Cuba

Integrability properties and invariant solutions of some biological models

In this research, we deal with the biological population‐related models called two‐dimensional Easter Island, Verhulst, and Lotka–Volterra and four‐dimensional MSEIR (M: Population, S: Suspected, E: Under Supervision, I: Infectious, R: Recovered) and SIRD (S: Suspected, I: Infectious, R: Recovered, D: Death) models by applying the artificial Hamiltonian method constructed for dynamical systems involving ordinary differential equations (ODEs) known as a partial Hamiltonian or nonstandard Hamiltonian system in the literature. This novel approach enables the investigation of the exact closed‐form solutions to dynamical systems of first‐order and second‐order ODEs that can be written as a nonstandard Hamiltonian system by utilizing common methods feasible to the nonstandard Hamiltonian systems. The first integrals and associated invariant solutions of the aforementioned biological and population models for some cases under the constraint of system parameters via the artificial Hamiltonian method for not only two‐dimensional but also four‐dimensional nonlinear dynamical systems are considered. Additionally, graphs of all population fractions for the SIRD model that show how they change over time for the subcase are presented and discussed.

Ralph L. Sacco, 65, Dies: Stroke Expert With a Talent for Architectural Design.

Ralph L. Sacco, 65, Dies: Stroke Expert With a Talent for Architectural Design.

Ralph L. Sacco, 65, Dies: Stroke Expert With a Talent for Architectural Design.

Ralph L. Sacco, 65, Dies: Stroke Expert With a Talent for Architectural Design.

Serological Determination of West Nile Virus in Domestic Birds from Rapa Nui, Chile.

Background: Flaviviruses are agents with high zoonotic potential of importance to human health. They are transmitted by mosquitoes of the Culicidae family, and birds act as host-amplifiers. Birds, mammals, and humans are susceptible hosts to infection. Methods: In this study, West Nile virus (WNV), flavivirus, infection was studied in 37 serum samples from 22 hens on Easter Island, Chile. Results: WNV was detected by ELISA (ID Screen® West Nile Competition Multi-Species). We report absence of antibodies to WNV, and to related viruses of the Japanese Encephalitis Virus serocomplex, and, therefore, absence of infection across the sample. Conclusion: This is the first evaluation of its type carried out in Chile, and represents a positive result for public health at Easter Island.

Integrating genetic and biophysical approaches to estimate connectivity in an isolated, insular system: case of the culturally important marine gastropod Monetaria caputdraconis

Abstract Population connectivity has a fundamental role in metapopulation dynamics with important implications for population persistence in space and time. Oceanic islands, such as Easter Island (EI) and the Salas & Gómez Island (SG), are ideal for the study of population connectivity because they are separated by 415 km and isolated from other islands in the Pacific Ocean by >2000 km. Considering that the dispersal process could play a critical role in the persistence of their populations, we evaluated the connectivity pattern of the endemic gastropod Monetaria caputdraconis between EI and SG using population genetics and biophysical modelling. Eleven microsatellite loci did not show differences in the allelic frequency of individuals located in EI and SG, suggesting the presence of one genetic population. Historical reciprocal migration implies that 0.49% of the recruits in EI come from SG and 0.37% in SG come from EI. Considering year-round larval release and a larval development of 2 weeks in the plankton, a Lagrangian experiment based on a regional oceanic simulation indicated a weak population connectivity with a high rate of self-recruitment. Interestingly, self-recruitment showed both monthly and interannual variation ranging from 1 to 45% of returned larvae, with lower values estimated in SG compared to EI. The results suggest that few larvae/individuals arrive at each other's island, possibly due to stochastic events, such as rafting. Overall, our results indicate that both islands maintain population connectivity despite their distance; these findings have implications for designing conservation strategies in this region.

ОРГАНИЗАЦИЯ САКРАЛЬНОГО ЛАНДШАФТА И АРХИТЕКТУРНОЙ ПЛАНИРОВКИ НАРОДОВ ОКЕАНИИ

The paper is about the description and analysis of methods and forms of organization of sacred landscape and religious architecture of the autochthonous people of the Pacific, to be compared to the first primitive forms of architectural art in Eurasia and Australia. The article discusses such elements of religious architecture of Polynesian peoples as the communal houses of the Maori of New Zealand, megalithic structures of Easter (Rapa Nui) island, as well as the marae ritual areas in Polynesia. A hypothesis is discussed that some of the elements of the most ancient sacred landscape of the Pacific may be considered universal for the development of human culture and spirituality. Similar forms could be considered as prototypes of the ancient sacred constructions and settlement architecture of Eurasia.