867 resultados para refugee influx
Resumo:
A piston sediment core E017 from the middle-southern Okinawa Trough was investigated. A preliminary study of the deep-water evolution since 18 cal. ka BP was performed based on the quantitative census data of benthic foraminiferal fauna, together with planktonic foraminiferal oxygen and carbon isotope, AMS(14)C dating, and the previous results achieved in the southern Okinawa Trough. The result shows that the benthic fauna was dominated by Bulimina aculeata (d'Orbigny), Uvigerina peregrina (Cushman), Hispid Uvigerina and Uvigerina dirupta (Todd) during the glaciation-deglaciation before 9.2 cal. ka BP, while Epistominella exigua (Brady), Pullenia bulloides (d'Orbigny), Cibicidoides hyalina (Hofker), Sphaeroidina bulloides (d'Orbigny) and Globocassidulina subglobosa (Brady) predominated the fauna in the post-glacial period after 9.2 cal. ka BP. The benthic foraminifera accumulation rate (BFAR), paleoproductivity estimates and benthic foraminiferal assemblage conformably indicate that surface water paleoproductivity and organic matter flux during the glaciation-deglaciation were higher than those of the post-glacial period in the middle-southern Okinawa Trough, and gradually enhanced from the southern to the central Okinawa Trough during the glaciation-deglaciation, which could be caused by the discrepancy of the terrigenous nutrients supply. High abundances of E exigua, an indicator of pulsed organic matter input, after 9.2 cal. ka. BP may indicate that the intensity of seasonally riverine pulsed flux during the post-glacial period was stronger than that of the glaciation-deglaciation period, and the seasonal influx in the central trough might be stronger than in the south. The temporal distributions of the typical species indicating bottom water oxygen content and ventilation condition show that the ventilation of the bottom water during the post-glacial period is more active than the glaciation-deglaciation, which reflects that the evolution of the intermediate and deep waters of the northwestern Pacific during the last glaciation has no evident influence on the deep-water of the middle-southern Okinawa Trough. Additionally, the variations in agglutinated benthic foraminiferal abundance and other carbonate dissolution proxies indicate that carbonate dissolution gradually increased since the last 18 ka in the Okinawa Trough and rapidly enhanced at 9.2 cal. ka BP. The modern shallow carbonate lysocline could form at 3 cal. ka BP.
Resumo:
To assess carbon budget for shrub ecosystems on the Qinghai-Tibet Plateau, CO2 flux was measured with an open-path eddy covariance system for an alpine shrub ecosystem during growing and non-growing seasons. CO2 flux dynamics was distinct between the two seasons. During the growing season from May to September, the ecosystem exhibited net CO2 uptake from 08:00 to 19:00 (Beijing Standard Time), but net CO2 emission from 19:00 to 08:00. Maximum CO2 uptake appeared around 12:00 with values of 0.71, 1,19, 1.46 and 0.67 g CO2 m(-2) h(-1) for June, July, August and September, respectively. Diurnal fluctuation Of CO2 flux showed higher correlation with photosynthetic photon flux density than temperature. The maximum net CO2 influx occurred in August with a value of 247 g CO2 m(-2). The total CO2 uptake by the ecosystem was up to 583 g CO2 m(-2) for the growing season. During the non-growing season from January to April and from October to December, CO2 flux showed small fluctuation with the largest net CO2 efflux of 0.30 g CO2 m(-2) h(-1) in April. The diurnal CO2 flux was close to zero during most time of the day, but showed a small net CO2 eff lux from 11:00 to 18:00. Diurnal CO2 flux, is significantly correlated to diurnal temperature in the non-growing season. The maximum monthly net CO2 eff lux appeared in April, with a value of 105 g CO2 m(-2). The total net CO2 eff lux for the whole non-growing season was 356 g CO2 m(-2).
Resumo:
[1] The alpine meadow ecosystem on the Qinghai-Tibetan Plateau may play a significant role in the regional carbon cycle. To assess the CO2 flux and its relationship to environmental controls in the ecosystem, eddy covariance of CO2, H2O, and energy fluxes was measured with an open-path system in an alpine meadow on the plateau at an elevation of 3,250 m. Net ecosystem CO2 influx (Fc) averaged 8.8 g m(-2) day(-1) during the period from August 9 to 31, 2001, with a maximum of 15.9 g m(-2) day(-1) and a minimum of 2.3 g m(-2) day(-1). Daytime Fc averaged 16.7 g m(-2) day(-1) and ranged from 10.4 g m(-2) day(-1) to 21.7 g m(-2) day(-1) during the study period. For the same photosynthetic photon flux density (PPFD), gross CO2 uptake (Gc) was significantly higher on cloudy days than on clear days. However, mean daily Gc was higher on clear days than on cloudy days. With high PPFD, Fc decreased as air temperature increased from 10degreesC to 23degreesC. The greater the difference between daytime and nighttime air temperatures, the more the sink was strengthened. Daytime average water use efficiency of the ecosystem (WUEe) was 8.7 mg (CO2)(g H2O)(-1); WUEe values ranged from 5.8 to 15.3 mg (CO2)(g H2O)(-1). WUEe increased with the decrease in vapor pressure deficit. Daily albedo averaged 0.20, ranging from 0.19 to 0.22 during the study period, and was negatively correlated with daily Fc. Our measurements provided some of the first evidence on CO2 exchange for a temperate alpine meadow ecosystem on the Qinghai-Tibetan Plateau, which is necessary for assessing the carbon budget and carbon cycle processes for temperate grassland ecosystems.
Resumo:
During the Devonian, a complicated carbonate platform-basin configuration was created through transtensional rifting in the context of opening of Devonian South China Sea; extensive bedded chert, commonly interbedded with tuffaceous beds, occurred in the narrow, elongate interplatform basins (or troughs) in South China, where they occurred earlier (Early Devonian) in southern Guangxi and later (early Late Devonian) in northern Guangxi-south central Hunan. In order to unravel the origin and distribution of the bedded chert successions, and their relationships to basement faulting activities during the opening of the Devonian South China Sea, studies of element (major, minor and REE) geochemistry and Rb-Sr, Sm-Nd isotopic systematics are carried out upon the chert deposits. These chert deposits commonly have high SiO2 contents and (average 94.01%) and low TFe2O3 (average 0.55%), together with other geochemical parameters, suggestive of both biogenic and hydrothermal origins. However, Fe/Ti ratio are high along the elongate interplatform basins(troughs) to the northwest along Wuxiangling-Zhaisha-Chengbu, and to the southeast along Xiaodong-Mugui-Xinpu, suggesting relatively intense hydrothermal activities there. They generally contain very low total REE contents (∑REE average 31.21ug/g) with mediate negative Ce anomalies (mean Ce/Ce*=0.83) and low Lan/Cen values (average 1.64), indicating an overall continental margin basin where they precipitated. The northward increases in Ce/Ce* values, particularly along the elongate troughs bounded both to the east and west of the Guangxi-Huanan rift basin, suggest a northward enhancement of terrigenous influences, thereby reflecting a gradual northward propagation of open marine setting. Generally low positive Eu anomalies in the chert, except for the apparently high Eu anomalies in the chert from Chengbu (Eu/Eu* up to 4.6), suggest mild hydrothermal venting activities in general, except for those at Chengbu. The initial 87Sr/86Sr (0) ratios of chert generally vary from 0.712000 to 0.73000 , suggesting influences both from terrigenous influx and seawater. The Nd isotopic model ages (tDM or t2DM) and initial εNd (0) values of chert vary mostly from 1.5 to 2.1 Ga, and from –16 to –21, respectively, implying that the silica sources were derived from the provenances of the Palaeoproterozoic crust relics at depth. The high εNd (0) values of chert (-0.22 to 14.7) in some localities, mostly along the elongate troughs, suggest that silica sources may have been derived from deeper-seated mantle, being channeled through the interplate boundary fault zones extending downwards to the mantle. At Wuxiangling, Nanning, chert occurs extensively from the Emsian through the Frasnian strata, both U/Th ratios and tDM ages of chert reached up to a maximum in the early Frasnian corresponding to the extensive development of chert in South China, pointing to a maximum extensional stage of Devonian South China basin, which is supported by the Ce/Ce* values as is opposed to the previous datasets as the coeval minimum values.
Resumo:
With the variations of solar activity, solar EUV and X-ray radiations change over different timescales (e.g., from solar cycle variation to solar flare burst). Since solar EUV and X-ray radiations are the primary energy sources for the ionosphere, theirs variations undoubtedly produce significant and complicated effects on the ionosphere. So the variations of solar activity significantly affect the ionosphere. It is essential for both ionospheric theory and applications to study solar activity effects on the ionosphere. The study about solar activity variations of the ionosphere is an important part of the ionospheric climatology. It can enhance the understanding for the basic processes in the ionosphere, ionospheric structure and its change, ionosphere/thermosphere coupling, and so on. As for applications, people need sufficient knowledges about solar activity variations of the ionosphere in order to improve ionospheric models so that more accurate forecast for the ionospheric environments can be made. Presently, the whole image about the modalities of ionospheric solar activity variations is still unknown, and related mechanisms still cannot be well understood. This paper is about the effects of the 11-year change in solar activity to the low- and mid-latitude ionosphere. We use multi-type ionospheric observations and model to investigate solar activity effects on the electron density and ionospheric spatial structure, and we focus on discussing some related mechanisms. The main works are as follows: Firstly, solar activity variations of ionospheric peak electron density (NmF2) around 1400 LT were investigated using ionosonde observations in the 120°E sector. The result shows that the variation trend of NmF2 with F107 depends on latitudes and seasons. There is obvious saturation trend in low latitudes in all seasons; while in middle latitudes, NmF2 increases linearly with F107 in winter but saturates with F107 at higher solar activity levels in the other seasons. We calculated the photochemical equilibrium electron density to discuss the effects induced by the changes of neutral atmosphere and dynamics processes on the solar activity variations of NmF2. We found that: (1) Seasonal variation of neutral atmosphere plays an important role in the seasonal difference of the solar activity variations of NmF2 in middle latitudes. (2) Less [O]/[N2] and higher neutral temperature are important for the saturation effect in summer, and the increase of vibrational excited N2 is also important for the saturation effect. (3) Dynamics processes can significantly weaken the increase of NmF2 when solar activity enhances, which is also a necessary factor for the saturation effect. Secondly, solar activity variations of nighttime NmF2 were investigated using ionosonde observations in the 120°E sector. The result shows that the variation trends of NmF2 with F107 in nighttime are different from that in daytime in some cases, and the nighttime variation trends depend on seasons. There is linear increase trend in equinox nighttime, and saturation trend in summer nighttime, while the increase rate of NmF2 with F107 increases when solar activity enhances in winter nighttime (we term it with “amplification trend”). We discussed the possible mechanisms which affect the solar activity variations of nighttime NmF2. The primary conclusions are as follows: (1) In the equatorial ionization anomaly (EIA) crest region, the plasma influx induced by the pre-reversal enhancement (PRE) results in the change of the variation trend between NmF2 and F107 from “saturation” to “linear” after sunset in equinoxes and winter; while the recombination process at the F2-peak is the primary factor that affects the variation trend of NmF2 with F107 in middle latitudes. (2) The recombination coefficient at the F2-peak height reaches its maximum at moderate solar activity level in winter nighttime, which induces NmF2 attenuates more quickly at moderate solar activity level. This is the main reason for the amplification trend. (3) The change of the recombination process at the F2-peak with solar activity depends on the increases of neutral parameters (temperature, density et al.) and the F2-peak height (hmF2). The seasonal differences in the changes of neutral atmosphere and hmF2 with solar activity are the primary reasons for the seasonal difference in the variation trend of nighttime NmF2 with F107. Finally, we investigated the solar activity dependence of the topside ionosphere in low latitudes using ROCSAT-1 satellite (at 600 km altitude) observations. The primary results and conclusions are as follows: (1) Latitudinal distribution of the plasma density is local time, seasonal, and solar activity dependent. In daytime, there is a plasma density peak at the dip equator. The peak is obviously enhanced at high solar activity level, and the strength of the peak strongly depends on seasons. While at sunset, two profound plasma density peaks (double-peak structure) are found in solar maximum equinox months. (2) Local time dependence of the latitudinal distribution is due to the local time variation of the equatorial dynamics processes. Double-peak structure is attributed to the fountain effect induced by strong PRE. Daytime peak enhances with solar activity since the plasma density increases with solar activity more strongly at the dip equator due to the equatorial vertical drift, and its seasonal dependence is mainly due to the seasonal variations of neutral density and the equatorial vertical drift. In the sunset sector, seasonal and solar activity dependences of the latitudinal distribution are related to the seasonal and solar activity variations of PRE. (3) The variation trend of the plasma density with solar activity shows local time, seasonal, and latitudinal differences. That is different from the changeless amplification trend at the DMSP altitude (840 km). Profound saturation effect is found in the dip equator region at equinox sunset. This saturation effect in the topside ionosphere is realated to the increase of PRE with solar activity. Solar activity variation trend of the topside plasma density was discussed quantitatively by Chapman-α function. The result shows that the effect induced by the change of the scale height is dominant at high altitudes; while the variation trend of ROCSAT-1 plasma density with solar activity is suggested to be related to the changes of the peak height, the scale height, and the peak electron density with solar activity.
Resumo:
Extensive high to ultrahigh pressure metamorphic rocks are outcropped in the the Dabie-Sulu UHP orogenic belt. Disputes still exist about for protolith nature of metamorphic rocks, petrogenesis, tectonic setting, and influence on upper mantle during the Triassic deep subduction. In this study, a combined study of petrology, geochemistry, isotope geochemistry and zircon chronology was accomplished for high-grade gneisses in the basement of the ultrahigh-pressure metamorphic Rongcheng terrane to reveal protolith nature and petrogenesis of the gneisses and to disucss the magmatic succession along the northern margin of the Yangtze block in Neoproterozoic. Gneisses in the Rongcheng terrane are characterized by negative Nb, Ta, P and Ti anomalies, relatively low Sr/Y ratios and relatively high Ba/La, Ba/Nb and Ba/Zr ratios, mostly displaying geochemical affinity to Phanerozoic volcanic arc. Neoproterozoic protolith ages (0.7 ~ 0.8 Ga) and Paleoproterozoic average crustal residence time (1.92 ~ 2.21 Ga) favour a Yangtze affinity. The gneisses mostly display characteristics of enrichment of LREE, flat heavy rare earth elements (REE) patterns, moderately fractionation between LREE and HREE and slight negative or positive Eu anomalies, probably reflecting that melting took place in the middle to low crust (26 ~ 33 km), where amphibole fractionated from the melts and/or inherited from source material as major mineral phases in the source area. Sr-Nd isotopic composition of the gneisses supports this conclusion. According to εNd(t) and εHf(t) values, the gneisses can be divided into three groups. Gneisses of group I have the highest εNd(t) and εHf(t) values, corresponding to the range of -6 ~ -3 and -2.9 ~ 13.4, respectively. This suggests obvious influx of depleted mantle or juvenile crust in the formation of protoliths. Gneisses of group II have medium εNd(t) (-9 ~ -7) and εHf(t) values (-15.8 ~ -1.4), corresponding to relatively high TDM2(Nd) (1.99 ~ 2.31 Ga) and TDM2(Hf) (1.76 ~ 2.67 Ga) , respectively. This suggests these gneisses were formed by partial melting of Paleoproterozoic crust. Gneisses of group III have the lowest εNd(t) (-15 ~ -10) and εHf(t) values (-15.8 ~ -1.4), corresponding to the largest TDM2(Nd) (1.99 ~ 2.31 Ga) and TDM2(Hf) ( 1.76 ~ 2.67 Ga), respectively. This indicates that gneisses of group III were formed by remelting of Archean crustal material and further demonstrates existence of an Archean basement probably of the Yangtze affinity beneath the Rongcheng terrane. Gneisses of three groups have also certain different geochemical characteristics. Contents of REEs and trace elements reduce gradually from group I to group III. Zirconium saturation temperatures also show similar tendency. Compared to gneisses of group II and group III, gneisses of group I display geochemical feature similar to extensional tectonic setting, having relatively little influence by the source area. Therefore, geochemical characteristics for gneisses of group I can indictate that the protoliths of the Rongcheng gneisses formed in an extensional rifting tectonic setting. This conclusion is supported by the results of eclogites and gabbros previously reported in the Dabie-Sulu orogenic belt. Statistical results of the protolith ages of the Rongcheng gneisses show two age peaks around ~728 Ma and ~783 Ma with an about 50 Ma gap. Extensive magatism in abou 750 Ma along the northern margin of the Yangtze block can hardly be observed in the Rongcheng terrane. This phenomenon likely suggests discontinuous Neoproterozoic magmatism along the northern margin of the Yangtze block.
Resumo:
Thomas, R., Urquhart, C., Crossan, S. & Hines, B. (2008). MUES (Mid Wales - Users - Ethnic Services) Ethnic services provision 2007-08. Report for Libraries for Life: Delivering the entitlement agenda for library users in Wales 2007-09. Aberystwyth: Department of Information Studies, Aberystwyth University. Related policy guidance published separately Sponsorship: CyMAL
Resumo:
J. H. Macduff and A. K. Bakken. (2003). Diurnal variation in uptake and xylem contents of inorganic and assimilated N under continuous and interrupted N supply to Phleum pratense and Festuca pratensis. Journal of Experimental Botany, 54 (381) pp.431-444 Sponsorship: BBSRC / Norwegian Crop Research Institute RAE2008
Resumo:
STUDY QUESTION. Are significant abnormalities in outward (K+) conductance and resting membrane potential (Vm) present in the spermatozoa of patients undertaking IVF and ICSI and if so, what is their functional effect on fertilization success? SUMMARY ANSWER. Negligible outward conductance (≈5% of patients) or an enhanced inward conductance (≈4% of patients), both of which caused depolarization of Vm, were associated with a low rate of fertilization following IVF. WHAT IS KNOWN ALREADY. Sperm-specific potassium channel knockout mice are infertile with defects in sperm function, suggesting that these channels are essential for fertility. These observations suggest that malfunction of K+ channels in human spermatozoa might contribute significantly to the occurrence of subfertility in men. However, remarkably little is known of the nature of K+ channels in human spermatozoa or the incidence and functional consequences of K+ channel defects. STUDY DESIGN, SIZE AND DURATION. Spermatozoa were obtained from healthy volunteer research donors and subfertile IVF and ICSI patients attending a hospital assisted reproductive techniques clinic between May 2013 and December 2015. In total, 40 IVF patients, 41 ICSI patients and 26 normozoospermic donors took part in the study. PARTICIPANTS/MATERIALS, SETTING, METHODS. Samples were examined using electrophysiology (whole-cell patch clamping). Where abnormal electrophysiological characteristics were identified, spermatozoa were further examined for Ca2+ influx induced by progesterone and penetration into viscous media if sufficient sample was available. Full exome sequencing was performed to specifically evaluate potassium calcium-activated channel subfamily M α 1 (KCNMA1), potassium calcium-activated channel subfamily U member 1 (KCNU1) and leucine-rich repeat containing 52 (LRRC52) genes and others associated with K+ signalling. In IVF patients, comparison with fertilization rates was done to assess the functional significance of the electrophysiological abnormalities. MAIN RESULTS AND THE ROLE OF CHANCE. Patch clamp electrophysiology was used to assess outward (K+) conductance and resting membrane potential (Vm) and signalling/motility assays were used to assess functional characteristics of sperm from IVF and ICSI patient samples. The mean Vm and outward membrane conductance in sperm from IVF and ICSI patients were not significantly different from those of control (donor) sperm prepared under the same conditions, but variation between individuals was significantly greater (P< 0.02) with a large number of outliers (>25%). In particular, in ≈10% of patients (7/81), we observed either a negligible outward conductance (4 patients) or an enhanced inward current (3 patients), both of which caused depolarization of Vm. Analysis of clinical data from the IVF patients showed significant association of depolarized Vm (≥0 mV) with low fertilization rate (P= 0.012). Spermatozoa with electrophysiological abnormities (conductance and Vm) responded normally to progesterone with elevation of [Ca2+]i and penetration of viscous medium, indicating retention of cation channel of sperm (CatSper) channel function. LIMITATIONS, REASONS FOR CAUTION. For practical, technical, ethical and logistical reasons, we could not obtain sufficient additional semen samples from men with conductance abnormalities to establish the cause of the conductance defects. Full exome sequencing was only available in two men with conductance defects. WIDER IMPLICATIONS OF THE FINDINGS. These data add significantly to the understanding of the role of ion channels in human sperm function and its impact on male fertility. Impaired potassium channel conductance (Gm) and/or Vm regulation is both common and complex in human spermatozoa and importantly is associated with impaired fertilization capacity when the Vm of cells is completely depolarized.
Resumo:
Celem publikacji jest podjęcie próby przeanalizowania polityki, jaką Turcja prowadzi wobec obcokrajowców poszukujących schronienia na jej terytorium. O ważkości zagadnienia zadecydowała w ostatnich latach przede wszystkim tocząca się w Syrii wojna domowa, w wyniku której na terytorium Turcji znalazło się ponad 700 tysięcy Syryjczyków. Szczególne w tym kontekście kontrowersje budzi fakt stosowania przez Turcję podwójnych standardów w przedmiocie nadawania imigrantom konwencyjnego statusu uchodźcy. Państwo to, jako jedno z czterech na świecie, w momencie przystępowania do Konwencji dotyczącej statusu uchodźców i Protokołu nowojorskiego zastrzegło sobie prawo do stosowania w tej materii tzw. kryterium geograficznego. W efekcie, o ile status uchodźcy nadany być może osobom przybywającym zza zachodnich granic Turcji, o tyle uciekinierzy z państw takich, jak Syria, Iran, czy Irak z formalnego punktu widzenia są „poszukującymi schronienia” (tur. sığınmacı). To zaś oznacza brak ich konwencyjnej ochrony. Celem artykułu jest jednak nie tylko przeanalizowanie prawnego i rzeczywistego położenia, w jakim znajdują się ofiary syryjskiej wojny domowej, przybywające na terytorium Turcji, a także próba przewidzenia scenariusza rozwoju tejże sytuacji. Celem uczynienia analizy możliwie najbardziej rzetelną, odwołano się zarówno do anglo, jak i tureckojęzycznych materiałów źródłowych.
Resumo:
Autor w pracy stawia tezę, że „francusko-niemiecki motor” odegrał pozytywną rolę w procesie integracji europejskiej w XX w. Dzięki bliskiej współpracy francusko-niemieckiej możliwa była realizacja unii walutowo-gospodarczej, Wspólna Polityka Zagraniczna i Bezpieczeństwa oraz stworzenie w UE „obszaru wolności, bezpieczeństwa i sprawiedliwości”. W XXI w. trudna sytuacja gospodarcza Francji i napięcia społeczne spowodowały spadek jej znaczenia w Unii Europejskiej. Kryzys finansowy strefy euro oraz problem uchodźców wykreowały Niemcy na samotnego lidera w Unii Europejskiej. Jednakże współpraca francusko-niemiecka nie załamała się, gdyż oba państwa wzajemnie się potrzebują i zapewniają równowagę w Europie. Zdaniem wielu ekspertów, ze względu na ogólne nastroje w Europie, w Berlinie i Paryżu brakuje nowych idei ukazujących perspektywy rozwojowe Unii Europejskiej na najbliższe lata.
Resumo:
This thesis focuses on the manner in which the EU, the UK, and Canada respond to and engage with the refugee’s movement from a temporary to a more permanent legal status in the state. It is noted that this transition is increasingly problematized. A trend is noted in response to this among the jurisdictions examined, to exceptionalise refugee status through acts of legal categorisation and separation. These categorisations represent an attempt to re-assert control over refugees who arrived to the state in a spontaneous manner. I argue that this categorisation and fragmentation of refugee status is another means of managing life in the state and ultimately excluding refugees within the state. Refugees therefore experience a contradictory response to their presence. While they are continually reminded of the temporary nature of their legal status in the state, they are still required to demonstrate a willingness to integrate in to the host society. Their behaviour in the state is something that is once again recalled by the decision makers who determine whether they should ultimately be able to access citizenship status. In this thesis, I argue that in order to navigate a route to citizenship, the refugee must respond to the constant re-framing and re-contextualisation of her status in the state of asylum. As the thesis observes, this raises broader questions about the nature of citizenship and belonging
Resumo:
Medical journals and other sources do not show evidence that cholera occurred in Haiti before 2010, despite the devastating effect of this disease in the Caribbean region in the 19th century. Cholera occurred in Cuba in 1833-1834; in Jamaica, Cuba, Puerto Rico, St. Thomas, St. Lucia, St. Kitts, Nevis, Trinidad, the Bahamas, St. Vincent, Granada, Anguilla, St. John, Tortola, the Turks and Caicos, the Grenadines (Carriacou and Petite Martinique), and possibly Antigua in 1850-1856; and in Guadeloupe, Cuba, St. Thomas, the Dominican Republic, Dominica, Martinique, and Marie Galante in 1865-1872. Conditions associated with slavery and colonial military control were absent in independent Haiti. Clustered populations, regular influx of new persons, and close quarters of barracks living contributed to spread of cholera in other Caribbean locations. We provide historical accounts of the presence and spread of cholera epidemics in Caribbean islands.
Resumo:
There are currently over two million Palestinian refugees residing in Jordan, 370,000 of whom reside in refugee camps. Due to conflict-affiliated disease outbreaks among children in the region, the UN Relief and Works Agency for Palestine Refugees (UNRWA) has identified incomplete vaccination as a critical public health issue and has invested in the development and implementation of a text message reminder service for preventing loss-to-follow-up. Childhood immunization rates in UNRWA catchment regions are generally high, yet little is known about risk factors for missed appointments, which impose a substantial administrative burden due to the need to contact patients for rescheduling. Stronger user characterization is necessary for improved targeting and minimized cost as we develop a more robust SMS system capable of scaling across all health facilities.
This mixed-methods study prospectively recorded 6 months of immunization history among a cohort of children born in June 2014 at Taybeh Health Center in Amman. Demographic information was collected at the time of birth, and caregivers of cohort members were invited to participate in interviews that assessed immunization knowledge, preferences, decision-making, and experience with the SMS reminder system. Patients were more likely to significantly delay appointments during the Ramadan holiday and for doses further from the child date of birth. Future policies that might bridge these gaps include targeting pre-appointment SMS reminders to high-risk patients, implementing holiday shifts in clinic hours, and regularly updating patient contact information.
Resumo:
Immunoglobulin superfamily (IgSF) domains are conserved structures present in many proteins in eukaryotes and prokaryotes. These domains are well-capable of facilitating sequence variation, which is most clearly illustrated by the variable regions in immunoglobulins (Igs) and T cell receptors (TRs). We studied an antibody-deficient patient suffering from recurrent respiratory infections and with impaired antibody responses to vaccinations. Patient's B cells showed impaired Ca(2+) influx upon stimulation with anti-IgM and lacked detectable CD19 membrane expression. CD19 sequence analysis revealed a homozygous missense mutation resulting in a tryptophan to cystein (W52C) amino acid change. The affected tryptophan is CONSERVED-TRP 41 located on the C-strand of the first extracellular IgSF domain of CD19 and was found to be highly conserved, not only in mammalian CD19 proteins, but in nearly all characterized IgSF domains. Furthermore, the tryptophan is present in all variable domains in Ig and TR and was not mutated in 117 Ig class-switched transcripts of B cells from controls, despite an overall 10% amino acid change frequency. In vitro complementation studies and CD19 western blotting of patient's B cells demonstrated that the mutated protein remained immaturely glycosylated. This first missense mutation resulting in a CD19 deficiency demonstrates the crucial role of a highly conserved tryptophan in proper folding or stability of IgSF domains.