Ophiolite hosted chromitite formed by supra-subduction zone peridotite–plume interaction

Chromitite bodies hosted in peridotites typical of suboceanic mantle(s.l.ophiolitic)are found in the northern and central part of the Loma Caribe peridotite,in the Cordillera Central of the Dominican Republic.These chromitites are massive pods of small size(less than a few meters across)and veins that intrude both dunite and harzburgite.Compositionally,they are high-Cr chromitites[Cr#=Cr/(Cr+Al)atomic ratio=0.71-0.83]singularly enriched in TiO2(up to 1.25 wt.%),Fe2 O3(2.77-9.16 wt.%)as well as some trace elements(Ga,V,Co,Mn,and Zn)and PGE(up to 4548 ppb in whole-rock).This geochemical signature is unknown for chromitites hosted in oceanic upper mantle but akin to those chromites crystallized from mantle plume derived melts.Noteworthy,the melt estimated to be in equilibrium with such chromite from the Loma Caribe chromitites is similar to basalts derived from different source regions of a heterogeneous Caribbean mantle plume.This mantle plume is responsible for the formation of the Caribbean Large Igneous Province(CLIP).Dolerite dykes with back-arc basin basalt(BABB)and enriched mid-ocean ridge basalt(E-MORB)affinities commonly intrude the Loma Caribe peridotite,and are interpreted as evidence of the impact that the Caribbean plume had in the off-axis magmatism of the back-arc basin,developed after the Caribbean island-arc extension in the Late Cretaceous.We propose a model in which chromitites were formed in the shallow portion of the back-arc mantle as a result of the metasomatic reaction between the supra-subduction zone(SSZ)peridotites and upwelling plume-related melts.

Discovery of unique African Helicobacter pylori CagAmultimerization motif in the Dominican Republic

BACKGROUND Helicobacter pylori(H.pylori)colonizes the human stomach and is a major cause of peptic ulcer disease and gastric cancer.However,although the prevalence of H.pylori is high in Africa,the incidence of gastric cancer is low,and this phenomenon is called to be African enigma.The CagA protein produced by H.pylori is the most studied virulence factor.The carcinogenic potential of CagA is associated with the Glu-Pro-Ile-Tyr-Ala(EPIYA)patterns and CagAmultimerization(CM)motifs.AIM To better understand the EPIYA patterns and CM motifs of the cagA gene.METHODS Gastric mucosal biopsy specimens were obtained from 258 patients with dyspepsia living in the Dominican Republic,from which 120 H.pylori strains were cultured.After the bacterial DNA extraction,the EPIYA pattern and CM motif genotypes were determined using a polymerase chain reaction-based sequencing.The population structure of the Dominican Republic strains was analyzed using multilocus sequence typing(MLST).Peptic ulcer disease and gastric cancer were identified via endoscopy,and gastric cancer was confirmed by histopathology.Histological scores of the gastric mucosa were evaluated using the updated Sydney system.RESULTS All CagA-positive strains carried the Western-type CagA according to the identified EPIYA patterns.Twenty-seven kinds of CM motifs were observed.Although the typical Western CM motif(FPLKRHDKVDDLSKVG)was observed most frequently,the typical East Asian CM motif(FPLRRSAAVNDLSKVG)was not observed.However,“FPLRRSAKVEDLSKVG”,similar to the typical East Asian CM motif,was found in 21 strains.Since this type was significantly more frequent in strains classified as hpAfrica1 using MLST analysis(P=0.034),we termed it Africa1-CM(Af1-CM).A few hpEurope strains carried the Af1-CM motif,but they had a significantly higher ancestral Africa1 component than that of those without the Af1-CM motif(P=0.030).In 30 cagA-positive strains,the"GKDKGPE"motif was observed immediately upstream of the EPIYA motif in the EPIYA-A segment,and there was a significant association between strains with the hpAfrica1 population and those containing the“GKDKGPE”motif(P=0.018).In contrast,there was no significant association between the CM motif patterns and histological scores and clinical outcomes.CONCLUSION We found the unique African CM motif in Western-type CagA and termed it Africa1-CM.The less toxicity of this motif could be one reason to explain the African enigma.

Moving toward Sustainable Rice Production in Northwest Dominican Republic

Pesticide runoff from the rice production area of Las Matas de Santa Cruz in NW Dominican Republic degrades biodiversity in the ecosystems of the Yaque del Norte River, Montecristi National Park, and Caribbean Sea. This degradation prompted the Dominican NGO AgroFrontera to develop a program for the creation of a new sustainable rice value chain, starting with the formation of a rice growers association in Las Matas. This project was to evaluate “organic” as a potential certification for the new growers association. The project found that while organic certification is years away, other barriers?to a sustainable rice value chain exist: competition with US rice imports due to Dominican Republic-Central American Free Trade Agreement?(DR-CAFTA),?an informal labor system, and access to credit. Recommendations for the new growers association include: to lower the cost of production to compete with imports, to formalize the labor system, to mediate financing for rice producers, and to maintain balanced leverage across the value chain. A recommendation for future research is the resiliency of farmer institutions against internal corruption and in-fighting.

The Impact of Hurricane Strikes on Short-Term Local Economic Activity: Evidence from Nightlight Images in the Dominican Republic

The Dominican Republic is highly exposed to adverse natural events that put the country at risk of losing hard-won economic, social, and environmental gains due to the impacts of disasters. This study used monthly nightlight composites in conjunction with a wind field model to econometrically estimate the impact of tropical cyclones on local economic activity in the Dominican Republic since 1992. It was found that the negative impact of storms lasts up to 15 months after a strike, with the largest effect observed after 9 months. Translating the reduction in nightlight intensity into monetary losses by relating it to quarterly gross domestic product(GDP) suggests that on average the storms reduced GDP by about USD 1.1 billion(4.5% of GDP 2000 and 1.5% of GDP 2016).

Prevalence of malaria and lymphatic filariasis in bateyes of the Dominican Republic

Background:The island of Hispaniola,shared by Haiti and the Dominican Republic(DR),is the only remaining malaria-endemic island in the Caribbean and accounts for 95%of the lymphatic filariasis(LF)burden in the Americas.Both countries aim to eliminate the diseases by 2020.Migration from Haiti,where both diseases are more prevalent,may promote transmission in the DR.Historically,Haitian migrant labourers live in rural Dominican agricultural'company towns'called boteyes,many of which received mass drug administration(MDA)for LF elimination.This study sought to determine the prevalence of malaria and LF in bateyes of the DR and to describe related risk faaors for disease.Methods:From March to April 2016,a cross-seaional,cluster survey was conduaed across Dominican boteyes stratified into three regions:southwest,north and east.A household questionnaire(n=776),captured demographics,ethnic origin,mobility patterns,malaria intervention coverage,and knowledge,and recent fever and treatment-seeking.Two individuals per household(n=1418)were tested for malaria parasites by microscopy and rapid diagnostic test(RDT)and LF antigen by filariasis test strip(FTS).Population-level estimates and confidence intervals(Cl)were computed adjusting for the survey design.Two-sided Hests compared differences in knowledge scores.Results:No(0%)blood sample was Plosm odium-positw e by microscopy or RDT.Six individuals were FTS-positive(0.5%;95%CI:0.2-1.5),but none(0%)of these were microfllariae-positive.Most botey residents were born in the DR(57.8%),documented(85.0%),and permanent residents(85.1%).Very few respondents(9.4%)reported travel to Haiti in the past year.Overall,half(53.8%)of respondents owned a bed net,and 82.3%of net owners reported using it the previous night.Indoor residual spraying(IRS)differed by region(range:4.7%-61.2%).Most of those with recent fever sought care(56.0%),yet only 30.5%of those seeking care were tested for malaria.Compared to Dominican-born populations,Haitian-born respondents more frequently reported recent fever,did not seek care for the fever,had not heard of malaria,and could not name symptoms or prevention methods.Conclusions:Malaria and LF transmission appear absent or extremely low in Dominican bateyes,which are a mixture of Haitian and Dominican residents.Travel to Haiti is rare,meaning risk of malaria and LF importation is low.Addressing identified gaps in intervention coverage,malaria knowledge,treatment seeking and service delivery will improve the quality of surveillance for these diseases,particularly among marginalized populations and promote island-wide elimination.

多米尼卡(Dominican)酒店 古老与现代的同台

将于2007年10月份开放的多米尼卡(Dominican)酒店,位于布鲁塞尔的市中心,国家歌剧院的后边。从地理位置上说,酒店所在的区是商务金融区,距离布鲁塞尔火车站走路10分钟,机场20分钟车程,从伦敦乘坐欧铁不到3个小时即到达。