230 research outputs found
Does export dependency hurt economic development? Empirical evidence from Singapore
A rapid export growth in East Asia was once identified as a source of the sustainable economic development that the region enjoyed. However, the current global recession has turned exports from an economic virtue to a vice. There is a growing awareness that a heavy reliance on exports has caused a serious economic downturn in the region. The present paper chooses Singapore as a case study to examine the relationship between the origin of the East Asian Miracle (i.e. export dependency) and the economic growth. For this purpose, the study employs a causality test developed by Toda and Yamamoto. The empirical findings indicate that despite a negative long-run relationship between export dependency and economic growth, Singapore's heavy reliance on exports does not seem to have produced negative effects on the nation's economic growth. This is because the increase in export dependency was an effect, and not a cause, of the country's output expansion.
Development of microsatellite markers for Permit (Trachinotus falcatus), cross-amplification in Florida Pompano (T. carolinus) and Palometa (T. goodei), and species delineation using microsatellite markers
Three of the 20 species in the genus Trachinotus, in the jack family, Carangidae, are found in Florida waters. These are Florida Pompano (T. carolinus), Permit (T. falcatus), and Palometa (T. goodei). Florida Pompano is a coastal pelagic species found in estuarine and marine waters; it spawns in multiple batches in offshore waters. Permit is the largest and longest lived of the three species and also spawns offshore in multiple batches, near reefs. As adults, Permit can be found nearshore and offshore and are often associated with reefs, but as juveniles they are common estuarine inhabitants. Palometa is a marine species, similar in size to Florida Pompano, and has the widest latitudinal distribution of the three species. Palometa spawn in offshore waters throughout the year with two peaks of activity. All three species support commercial or recreational fisheries on both the Gulf of Mexico coast and Atlantic coast of Florida. Very little has been done to evaluate movement patterns of Trachinotus species. Based on a few tagging studies, it appears that Pompano do not travel far from coastal waters.
The only preliminary investigation of genetic stock structure for the Florida Pompano population from Tampa Bay, FL, and Puerto Rico was based on microsatellite markers developed for the Pompano. The report’s key conclusion was that Pompano from Puerto Rico and from Florida belong to two highly distinct genetic stocks.
This study was conducted to re-examine, using different microsatellite markers, the genetic status of Pompano stocks in Florida and Puerto Rico. The objectives of this study, therefore, were the following: 1) to develop microsatellite markers for Permit; 2) to cross-amplify the markers in Pompano and Palometa; and 3) to use these markers to confirm the status of Puerto Rico Pompano as a novel genetic stock using the methods of Bayesian population assignment, phylogenetic clustering, and factorial correspondence analysis. ... Three methods were used to investigate the relationship among the taxa using the microsatellite genotype data obtained from the samples. The results from the three analytical methods, based on Bayesian population assignment tests, phylogenetic clustering, and factorial correspondence analysis of genetic relationships among the four Trachinotus samples, showed that Florida and Puerto Rico Pompano samples belong to two highly distinct gene pools. But other multiple molecular tools, particularly nuclear-DNA sequences from many introns, and nonmolecular tools, such as morphological and meristic data, should be used together to determine species-level categorical designation for the Puerto Rico Pompano
Protective Efficacy of Menthol Propylene Glycol Carbonate Compared to N, N-diethyl-Methylbenzamide Against Mosquito Bites in Northern Tanzania.
The reduction of malaria parasite transmission by preventing human-vector contact is critical in lowering disease transmission and its outcomes. This underscores the need for effective and long lasting arthropod/insect repellents. Despite the reduction in malaria transmission and outcomes in Tanzania, personal protection against mosquito bites is still not well investigated. This study sought to determine the efficacy of menthol propylene glycol carbonate (MR08), Ocimum suave as compared to the gold standard repellent N, N-diethyl-methylbenzamide (DEET), either as a single dose or in combination (blend), both in the laboratory and in the field against Anopheles gambiae s.l and Culex quinquefasciatus. In the laboratory evaluations, repellents were applied on one arm while the other arm of the same individual was treated with a base cream. Each arm was separately exposed in cages with unfed female mosquitoes. Repellents were evaluated either as a single dose or as a blend. Efficacy of each repellent was determined by the number of mosquitoes that landed and fed on treated arms as compared to the control or among them. In the field, evaluations were performed by human landing catches at hourly intervals from 18:00 hr to 01:00 hr. A total of 2,442 mosquitoes were collected during field evaluations, of which 2,376 (97.30%) were An. gambiae s.l while 66 (2.70%) were Cx. quinquefaciatus. MR08 and DEET had comparatively similar protective efficacy ranging from 92% to 100 for both single compound and blends. These findings indicate that MR08 has a similar protective efficacy as DEET for personal protection outside bed nets when used singly and in blends. Because of the personal protection provided by MR08, DEET and blends as topical applicants in laboratory and field situations, these findings suggest that, these repellents could be used efficiently in the community to complement existing tools. Overall, Cx. quinquefasciatus were significantly prevented from blood feeding compared to An. gambiae s.l. The incorporation of these topical repellents for protection against insect bites can be of additional value in the absence or presence of IRS and ITNs coverage. However, a combination of both the physical (bed nets) and the repellent should be used in an integrated manner for maximum protection, especially before going to bed. Additional research is needed to develop repellents with longer duration of protection
Evaluation of alternative mosquito sampling methods for malaria vectors in Lowland South - East Zambia.
Sampling malaria vectors and measuring their biting density is of paramount importance for entomological surveys of malaria transmission. Human landing catch (HLC) has been traditionally regarded as a gold standard method for surveying human exposure to mosquito bites. However, due to the risk of human participant exposure to mosquito-borne parasites and viruses, a variety of alternative, exposure-free trapping methods were compared in lowland, south-east Zambia. Centres for Disease Control and Prevention miniature light trap (CDC-LT), Ifakara Tent Trap model C (ITT-C), resting boxes (RB) and window exit traps (WET) were all compared with HLC using a 3 × 3 Latin Squares design replicated in 4 blocks of 3 houses with long lasting insecticidal nets, half of which were also sprayed with a residual deltamethrin formulation, which was repeated for 10 rounds of 3 nights of rotation each during both the dry and wet seasons. The mean catches of HLC indoor, HLC outdoor, CDC-LT, ITT-C, WET, RB indoor and RB outdoor, were 1.687, 1.004, 3.267, 0.088, 0.004, 0.000 and 0.008 for Anopheles quadriannulatus Theobald respectively, and 7.287, 6.784, 10.958, 5.875, 0.296, 0.158 and 0.458, for An. funestus Giles, respectively. Indoor CDC-LT was more efficient in sampling An. quadriannulatus and An. funestus than HLC indoor (Relative rate [95% Confidence Interval] = 1.873 [1.653, 2.122] and 1.532 [1.441, 1.628], respectively, P < 0.001 for both). ITT-C was the only other alternative which had comparable sensitivity (RR = 0.821 [0.765, 0.881], P < 0.001), relative to HLC indoor other than CDC-LT for sampling An. funestus. While the two most sensitive exposure-free techniques primarily capture host-seeking mosquitoes, both have substantial disadvantages for routine community-based surveillance applications: the CDC-LT requires regular recharging of batteries while the bulkiness of ITT-C makes it difficult to move between sampling locations. RB placed indoors or outdoors and WET had consistently poor sensitivity so it may be useful to evaluate additional alternative methods, such as pyrethrum spray catches and back packer aspirators, for catching resting mosquitoes
Mean Field Theory of Josephson Junction Arrays with Charge Frustration
Using the path integral approach, we provide an explicit derivation of the
equation for the phase boundary for quantum Josephson junction arrays with
offset charges and non-diagonal capacitance matrix. For the model with nearest
neighbor capacitance matrix and uniform offset charge , we determine,
in the low critical temperature expansion, the most relevant contributions to
the equation for the phase boundary. We explicitly construct the charge
distributions on the lattice corresponding to the lowest energies. We find a
reentrant behavior even with a short ranged interaction. A merit of the path
integral approach is that it allows to provide an elegant derivation of the
Ginzburg-Landau free energy for a general model with charge frustration and
non-diagonal capacitance matrix. The partition function factorizes as a product
of a topological term, depending only on a set of integers, and a
non-topological one, which is explicitly evaluated.Comment: LaTex, 24 pages, 8 figure
Critical properties of two-dimensional Josephson junction arrays with zero-point quantum fluctuations
We present results from an extensive analytic and numerical study of a
two-dimensional model of a square array of ultrasmall Josephson junctions. We
include the ultrasmall self and mutual capacitances of the junctions, for the
same parameter ranges as those produced in the experiments. The model
Hamiltonian studied includes the Josephson, , as well as the charging,
, energies between superconducting islands. The corresponding quantum
partition function is expressed in different calculationally convenient ways
within its path-integral representation. The phase diagram is analytically
studied using a WKB renormalization group (WKB-RG) plus a self-consistent
harmonic approximation (SCHA) analysis, together with non-perturbative quantum
Monte Carlo simulations. Most of the results presented here pertain to the
superconductor to normal (S-N) region, although some results for the insulating
to normal (I-N) region are also included. We find very good agreement between
the WKB-RG and QMC results when compared to the experimental data. To fit the
data, we only used the experimentally determined capacitances as fitting
parameters. The WKB-RG analysis in the S-N region predicts a low temperature
instability i.e. a Quantum Induced Transition (QUIT). We carefully simulations
and carry out a finite size analysis of as a function of the
magnitude of imaginary time axis . We find that for some relatively
large values of (, the
limit does appear to give a {\it non-zero} , while
for , . We use the SCHA to analytically understand
the dependence of the QMC results with good agreement between them.
Finally, we also carried out a WKB-RG analysis in the I-N region and found no
evidence of a low temperature QUIT, up to lowest order in Comment: 39 pages, 18 postscript figures, to appear in Phys. Rev.
Identification of mosquito repellent odours from Ocimum forskolei
<p>Abstract</p> <p>Background</p> <p>Native mosquito repellent plants have a good potential for integrated mosquito control in local settings. <it>Ocimum forskolei</it>, Lamiaceae, is used in Eritrea as a spatial mosquito repellent inside houses, either through crushing fresh plants or burning dry plants. We verified whether active repellent compounds could be identified using gas-chromatography coupled electroantennogram recordings (GC-EAD) with headspace extracts of crushed plants.</p> <p>Results</p> <p>EAD active compounds included (R)-(-)-linalool, (S)-(+)-1-octen-3-ol, trans-caryophyllene, naphthalene, methyl salicylate, (R)-(-)-α-copaene, methyl cinnamate and (E)-ocimene. Of these compounds (R)-(-)-linalool, methyl cinnamate and methyl salicylate reduced landing of female <it>Aedes aegypti </it>on human skin-odor baited tubes. The latter two are novel mosquito repellent compounds.</p> <p>Conclusions</p> <p>The identification of mosquito repellent compounds contributes to deciphering the mechanisms underlying repulsion, supporting the rational design of novel repellents. The three mosquito repellent compounds identified in this study are structurally dissimilar, which may indicate involvement of different sensory neurons in repulsion. Repulsion may well be enhanced through combining different repellent plants (or their synthetic mimics), and can be a locally sustainable part in mosquito control efforts.</p
The burden of diabetes mellitus during pregnancy in low- and middle-income countries : a systematic review
Peer reviewedPublisher PD
Advantages and Limitations of Commercially Available Electrocuting Grids for Studying Mosquito Behaviour.
Mosquito feeding behaviour plays a major role in determining malaria transmission intensity and the impact of specific prevention measures. Human Landing Catch (HLC) is currently the only method that can directly and consistently measure the biting rates of anthropophagic mosquitoes, both indoors and outdoors. However, this method exposes the participant to mosquito-borne pathogens, therefore new exposure-free methods are needed to replace it. Commercially available electrocuting grids (EGs) were evaluated as an alternative to HLC using a Latin Square experimental design in Dar es Salaam, Tanzania. Both HLC and EGs were used to estimate the proportion of human exposure to mosquitoes occurring indoors (πi), as well as its two underlying parameters: the proportion of mosquitoes caught indoors (Pi) and the proportion of mosquitoes caught between the first and last hour when most people are indoors (Pfl). HLC and EGs methods accounted for 69% and 31% of the total number of female mosquitoes caught respectively and both methods caught more mosquitoes outdoors than indoors. Results from the gold standard HLC suggest that An. gambiae s.s. in Dar es Salaam is neither exophagic nor endophagic (Pi ≈ 0.5), whereas An. arabiensis is exophagic (Pi < < 0.5). Both species prefer to feed after 10 pm when most people are indoors (Pfl > >0.5). EGs yielded estimates of Pi for An. gambiae s.s., An. arabiensis and An. coustani, that were approximately equivalent to those with HLC but significantly underestimated Pfl for An. gambiae s.s. and An. coustani. The relative sampling sensitivity of EGs declined over the course of the night (p ≤ 0.001) for all mosquito taxa except An. arabiensis. Commercial EGs sample human-seeking mosquitoes with high sensitivity both indoors and outdoors and accurately measure the propensity of Anopheles malaria vectors to bite indoors rather than outdoors. However, further modifications are needed to stabilize sampling sensitivity over a full nocturnal cycle so that they can be used to survey patterns of human exposure to mosquitoes
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