Small Plastic Containers Research Articles

Occurrence of legacy and replacement plasticizers, bisphenols, and flame retardants in potable water in Montreal and South Africa

The occurrence of thirty-nine contaminants including plasticizers, bisphenols, and flame retardants in potable water from Montreal and South Africa was analyzed to determine their presence and concentrations in different water sources. In Montreal, five bottled water (BW) brands and three drinking water treatment plants (DWTP) were included. In South Africa, water was sampled from one urban DWTP located in Pretoria, Gauteng, and one rural DWTP located in Vhembe, along with water from the same rural DWTP which had been stored in small and large plastic containers. A combination of legacy compounds, typically with proven toxic effects, and replacement compounds was investigated. Bisphenols, Dechlorane-602, Dechlorane-603, and s-dechlorane plus (s-DP) were not detected in any water samples, and a-dechlorane plus (a-DP) was only detected in one sample from Pretoria at a concentration of 1.09 ng/L. Lower brominated polybrominated diphenyl ethers (PBDE)s were detected more frequently than higher brominated PBDEs, always at low concentrations of <2 ng/L, and total PBDE levels were statistically higher in South Africa than in Montreal. Replacement flame retardants, organophosphate esters (OPEs), were detected at statistically higher concentrations in Montreal's BW (68.56 ng/L), drinking water (DW) (421.45 ng/L) and Vhembe (198.33 ng/L) than legacy PBDEs. Total OPE concentrations did not demonstrate any geographical trend; however, levels were statistically higher in Montreal's DW than Montreal's BW. Plasticizers were frequently detected in all samples, with legacy compounds DEHP, DBP, and replacement DINCH being detected in 100 % of samples with average concentrations ranging from 6.89 ng/L for DEHP in Pretoria to 175.04 ng/L for DINCH in Montreal's DW. Total plasticizer concentrations were higher in Montreal than in South Africa. The replacement plasticizers (DINCH, DINP, DIDA, and DEHA) were detected at similar frequencies and concentrations as legacy plasticizers (DEHP, DEP, DBP, MEHP). For the compounds reported in earlier studies, the concentrations detected in the present study were similar to other locations. These compounds are not currently regulated in drinking water but their frequent detection, especially OPEs and plasticizers, and the presence of replacement compounds at similar or higher levels than their legacy compounds demonstrate the importance of further investigating the prevalence and the ecological or human health effects of these compounds.

Mass Screening of COVID-19 Cases by Sputum Testing

SARS CoV 2 virus is detected in the respiratory tract by using nasal/oropharyngeal and nasal mid-turbinate swabs, nasopharyngeal wash and aspirate, and an oral aspirate. The anterior nares are the most common place to collect samples due to its ease and little invasiveness. Sample collection requires experienced hands, and if the appropriate technique isn't followed, it might lead to false negative results and alter the final conclusion. Because of its size and robustness, India's healthcare system has over 700 districts each running National Tuberculosis Elimination Program (NTEP) and experts in India have proposed modifying the CBNAAT machines used in NTEP program for COVID 19 testing by utilizing a new cartridge. After a second wave of COVID-19 cases, the number of cases in India is on the rise again. When dealing with a highly contagious disease, healthcare professionals are constrained by a lack of personal protective equipment, logistics, and infrastructure. The nasopharyngeal specimen and the procedure involved, make it a more difficult and riskier affair for healthcare practitioners to perform. If COVID-19 is combated with the NTEP's current infrastructure, human resources, and logistics, we believe that early detection of cases and overall containment will be maximized. Sputum samples can be self-collected in small plastic containers and sent to the nearest tuberculosis unit for CBNAAT analysis instead of using the professional technique of collecting nasopharyngeal swabs in Viral Transport Media. Sputum sample collection is a simple operation. Be it in urban tertiary care facilities or a rural subcentre. To collect sputum, healthcare staff can simply assist. In the current phase of the pandemic in India, where the majority of COVID-19 infections are asymptomatic, mass screening at the community level using effective testing specimens and methodologies becomes critical and the only choice. It would make sense to collect COVID-19 samples at the community level based on the scientific evidence in such a scenario, especially for a country with a population of over 1.3 billion people.

A new liquid density measurement method based on elastic spring stretching

A simple method is described for measuring liquid density based on stretching of the spring and equilibrium of weight and elastic force. The method involves placing a container with liquid under test on the spring causing a stretch of the spring that is directly proportional to the weight of the liquid. With this technique, the liquid density can be determined without measuring its mass and volume, and it should help students comprehend the concept of density more easily. The design of the measuring setup in this study is made using tools and materials that are simple and easy to obtain, such as spring, ruler, and small plastic or metallic container (tube). Two liquids used to test the measuring method were ethanol and glycerol. A test showed that the density of the test liquids at room temperature could be measured with the relative uncertainty of 3%, hence the reliability of the described method was confirmed.

Semi-Field Evaluation of Modified 00ZZZero® Traps with Sticky Paper to Increase the Collection Efficacy of Gravid Aedes aegypti.

The 00ZZZero® trap (0Z) is a small black plastic container with permethrin and pyriproxyfen, designed and marketed to both attract and kill gravid Aedes mosquitoes (unmodified trap ([UMT] or modified trap [MT]). The 0Z trap without the insecticide was modified with addition of a sticky paper, coated with an adhesive glue (MT) and evaluated for collection efficacy of released gravid mosquito, Aedes aegypti (L.) in outdoor screened enclosures in St. Augustine, in northeastern Florida. The mean numbers (±SE) of mosquitoes caught by MTs were 130.67 ± 23.95 (40.22 ± 5.78 mosquito/trap), compared with 2.33 ± 0.88 (0.79 ± 0.29 mosquito/trap) mosquitoes caught by UMTs. The MTs collected significantly more mosquitoes, 44.16% (F = 4.495, P < 0.05) of the released mosquitoes, than those captured in UMTs (0.83%). The number of immature mosquitoes (larvae and pupae) hatched from eggs laid in the MTs and UMTs were 79.3 ± 23.1 and 19.3 ± 6.8, respectively. The mean numbers (±SE) of adults emerging in MTs and UMTs were 34.0 ± 22.3 and 14.0 ± 6.8, respectively. These results show the potential of the sticky paper modified 0Z traps to be used both to increase the efficacy of collection and as a sticky autocidal tool against gravid Ae. aegypti.

Further Progress in the Electrostatic Nucleation of Water Vapor

The planet's atmosphere holds a vast amount of water. Existing state-of-the-art “atmospheric water generation” systems mostly work by cooling the entire air flow below the dew point, which require significant amounts of energy per liter of water. As a result, the cost of this water is similar to that of imported bottled water in small single-use plastic containers. Therefore, there is an urgent need for any technology that generates usable water in an energy-efficient manner. It is known that the native dipole moment of water molecule results in the nucleation of liquid phase on carriers of electrical charge due to the suppressed evaporation. Nevertheless, the practical implementation of electrostatic water nucleation (EWN) is still in the stage of laboratory demonstrations. This work summarizes the theoretical background of the phenomenon and past experimental data, presents further experimental results and new data from practical implementation of EWN, and analyzes options for the further development.

Improving the built environment in urban areas to control Aedes aegypti-borne diseases.

The vector Aedes aegypti is now present in nearly every tropical and sub-tropical region in the world and poses a threat to health globally. The mosquito can transmit several viruses that cause diseases, such as dengue fever, chikungunya, yellow fever and Zika virus infection. Recent outbreaks of Ae. aegypti-borne diseases have shown that urban areas are particularly vulnerable because the built environment provides ideal conditions for mosquito proliferation and contact with humans. Unless the global public health community takes a coordinated, pre-emptive approach to controlling the Ae. aegypti population, these outbreaks will become more common and widespread as urban populations expand and movement of people and their goods increase. Improving the built environment would contribute to a long-term solution to reducing the threat of Ae. aegypti-bome diseases. Our ability to deal with Ae. Aegypti-borne viral epidemics is limited. Apart from supportive care, specific treatments for vector-borne viral diseases are lacking. No commercial vaccines for Zika or chikungunya are available, the only licensed dengue vaccine is partially protective (1) and globally the yellow fever vaccine is in short supply. (2) Although current vector control programmes are often poorly resourced and under-used, (3) historically, vector control was the main method for controlling mosquito-borne diseases. By using container inspections, oiling of breeding sites and later perifocal spraying of DDT (dichlorodiphenyltrichloroethane) in water containers and on nearby walls, Ae. aegypti, yellow fever and dengue fever were successfully eliminated from much of South America in the 1960s. (4) In the 1970s and 1980s in Singapore and in the 1980s and 1990s in Cuba, controlling adult and larval Ae. aegypti reduced dengue transmission. In the future, new methods of vector control, such as novel delivery systems for insecticides with new modes of action and release of Wolbachia-infected or genetically-modified mosquitoes, may contribute to the control or elimination of mosquito-borne diseases. (5) Affected towns and cities, however, already have several options to reduce Ae. aegyptibome diseases and these options should be built into future planning strategies. Current Ae. aegypti control focuses on reducing densities of immature and adult mosquitoes with larvicides or adult insecticides. While these interventions can be effective, continued reliance on these single-intervention control programmes is resource-intensive and threatened by insecticide resistance. The World Health Organization (3,6) and other major international organizations7 have recommended an intersectoral approach to achieve more effective and sustainable vector control. Governments, however, have often overlooked such approaches when designing vector control programmes. An underutilized aspect of integrated vector management is improving the urban built environment to reduce Ae. aegypti populations and their contact with humans. (8) The built environment in many urban areas provides abundant habitats for the immature stages of Ae. aegypti, and high human population densities create the potential for large outbreaks of Aedes-borne diseases. More than half of the world's population currently lives in urban areas and by 2050 it is estimated that 70% of the population will live in cities. (9) This urban expansion will increase the frequency and intensity of Aedes-borne outbreaks. However, developing urban areas that minimize human contact with mosquitoes could enable sustainable and cost-effective prevention of mosquito-borne diseases. Several aspects of urban planning can be targeted to reduce human contact with Ae. aegypti. Reducing the availability of small plastic containers around homes and improving solid waste management will remove habitats for Ae. aegypti larvae development. Provision of constant piped water will reduce the need to store water in containers in and around homes, since water-filled containers are known to be favoured habitats for Ae. …

BIOLOGY AND INTRINSIC GROWTH RATE OF EARWIG (Euborellia annulata)

Earwig (Euborellia annulata) is a potential predator of corn borer (Ostrinia furnacalis), one of the most important pests of corn. To include the use of predator in integrated pest management (IPM) to control the pest, it is necessary to understand the basic information of the predator. This study aimed to know biology and intrinsic growth rate of the predator feed on an artificial media (dog food). Ten pairs of newly emerging adults of the predator were placed in a small plastic container containing a mixture of soil and sand (1:1 v/v) supplemented with an artificial food. The average temperature and relative humidity during the study were kept at 27.9-30.3oC and 76.7-92.3%, respectively. The biological aspects of the predator evaluated were number of eggs laid, hatched, and died, as well as its oviposition period and adult mortality. The intrinsic growth rate was studied from a group of 200 newly laid eggs and results were analyzed based on the method of Birch. The biological aspects study showed that number of eggs laid by a single female of E. annulata was 86-166, which were laid five times in a group of 9-45 eggs. The nymph consists of five instars. Length of nymphs varied ranging from 4 to 13 mm depends on their instar. The fifth instar nymph period was 4-6 days for female and 2-3 days for male. The period of first mating was shorter; the shortest was 2 minutes and the longest one was 70 minutes. Both male and female were able to do mating several times at an interval of several seconds or minutes. Pre-oviposition period was 6-13 days. The eggs were deposited five times, the first, second, third, fourth, and fifth oviposition period were 7-22 days, 7-21 days, 7-18 days, 11-18 days, and 11-21 days, respectively. The oviposition period was 32-59 days and postoviposition period was 21-51 days. Ratio between male and female was 1.4:1.0. The average natural mortality of E. annulata was 10.5% which means that 89.5% of deposited eggs hatched became nymphs. The study also revealed that the intrinsic growth rate (r) of the predator was 0.0772, net reproductive rate (R0) 80.16, limited growth rate (λ) 1.17, nymph stage period 39-46 days, and adult longevity of male and female were 57-75 and 61-89 days, respectively. The study implies that E. annulata is potential to be incorporated in IPM for controlling corn borer.

BIOLOGY AND INTRINSIC GROWTH RATE OF EARWIG (Euborellia annulata)

Earwig (Euborellia annulata) is a potential predator of corn borer (Ostrinia furnacalis), one of the most important pests of corn. To include the use of predator in integrated pest management (IPM) to control the pest, it is necessary to understand the basic information of the predator. This study aimed to know biology and intrinsic growth rate of the predator feed on an artificial media (dog food). Ten pairs of newly emerging adults of the predator were placed in a small plastic container containing a mixture of soil and sand (1:1 v/v) supplemented with an artificial food. The average temperature and relative humidity during the study were kept at 27.9-30.3oC and 76.7-92.3%, respectively. The biological aspects of the predator evaluated were number of eggs laid, hatched, and died, as well as its oviposition period and adult mortality. The intrinsic growth rate was studied from a group of 200 newly laid eggs and results were analyzed based on the method of Birch. The biological aspects study showed that number of eggs laid by a single female of E. annulata was 86-166, which were laid five times in a group of 9-45 eggs. The nymph consists of five instars. Length of nymphs varied ranging from 4 to 13 mm depends on their instar. The fifth instar nymph period was 4-6 days for female and 2-3 days for male. The period of first mating was shorter; the shortest was 2 minutes and the longest one was 70 minutes. Both male and female were able to do mating several times at an interval of several seconds or minutes. Pre-oviposition period was 6-13 days. The eggs were deposited five times, the first, second, third, fourth, and fifth oviposition period were 7-22 days, 7-21 days, 7-18 days, 11-18 days, and 11-21 days, respectively. The oviposition period was 32-59 days and postoviposition period was 21-51 days. Ratio between male and female was 1.4:1.0. The average natural mortality of E. annulata was 10.5% which means that 89.5% of deposited eggs hatched became nymphs. The study also revealed that the intrinsic growth rate (r) of the predator was 0.0772, net reproductive rate (R0) 80.16, limited growth rate (λ) 1.17, nymph stage period 39-46 days, and adult longevity of male and female were 57-75 and 61-89 days, respectively. The study implies that E. annulata is potential to be incorporated in IPM for controlling corn borer.

Is This Exercise? No, It’s Geocaching! Exploring Factors Related to Aspects of Geocaching Participation

Geocaching is a way to integrate technology with physical activity. Geocaching utilizes a global positioning receiver system (GPS) that provides coordinates directing participants to find treasures or “caches.” With the continued concern over decreased physical activity participation in youth, it was considered that geocaching may be one way to increase physical activity among youth as its novel, fun, and involves technology. From a programming perspective, geocaching may be used as a large special event, drop-in activity, or after-school program. It can be performed as an individual or group. Since it is a relatively new activity, specifically for youth, we were interested in the factors related to geocaching, including psychosocial factors associated with physical activity participation, to determine if geocaching may be of interest for youth physical activity programming. We recruited youth, aged 14–18 years, from a high school in rural western North Carolina. Since geocaching was a novel activity to this group, we created an infrastructure and made our own geocaching course and developed caches while using the www. geocaching.com website. The caches used were small plastic containers that contained a notebook for participants to record their names once found. These caches were set up using GPS coordinates; however, written instructions and clues were also provided. Finally, participants were placed into groups of three to four, and each group was provided with its own GPS receiver. A sample geocache session that had one cache site with clues was performed by each group to make sure they understand the process. In order to further understand the potential geocaching has for improving physical activity participation in youth we had all participants complete a series of questions. The surveys assessed current PA behaviors as well as psychosocial factors including social support of friends and family, self-efficacy, and PA attitudes and behaviors. Additionally, items were created to determine interest and ability for geocaching for this study, as no other geocache scales were available. Results from the Geocaching Interests/Abilities scale created by the authors indicated youth scored high on questions asking if looking for hidden treasures would be fun and more fun than walking. Youth also reported preferences for being outside and enjoyment in using technology. Correlation analysis revealed significant relationships between psychosocial variables and reported PA, but little to no relationship between psychosocial variables and Geocaching Interests/Abilities. Results suggest youth are interested in geocaching regardless of gender, reported PA levels, or traditional psychosocial factors such as social support and self-efficacy. The geocaching program we designed would be an easy one to replicate in any after-school setting or youth group. From a practitioner perspective, geocaching may be an effective way to engage youth in physical activity in a nontraditional manner. In order to promote geocaching at a facility developing brochures, providing signage or using social media may assist in providing sites other ways to promote physical activity to clients.

Characterization of energy response for photon-counting detectors using x-ray fluorescence.

To investigate the feasibility of characterizing a Si strip photon-counting detector using x-ray fluorescence. X-ray fluorescence was generated by using a pencil beam from a tungsten anode x-ray tube with 2 mm Al filtration. Spectra were acquired at 90° from the primary beam direction with an energy-resolved photon-counting detector based on an edge illuminated Si strip detector. The distances from the source to target and the target to detector were approximately 19 and 11 cm, respectively. Four different materials, containing silver (Ag), iodine (I), barium (Ba), and gadolinium (Gd), were placed in small plastic containers with a diameter of approximately 0.7 cm for x-ray fluorescence measurements. Linear regression analysis was performed to derive the gain and offset values for the correlation between the measured fluorescence peak center and the known fluorescence energies. The energy resolutions and charge-sharing fractions were also obtained from analytical fittings of the recorded fluorescence spectra. An analytical model, which employed four parameters that can be determined from the fluorescence calibration, was used to estimate the detector response function. Strong fluorescence signals of all four target materials were recorded with the investigated geometry for the Si strip detector. The average gain and offset of all pixels for detector energy calibration were determined to be 6.95 mV/keV and -66.33 mV, respectively. The detector's energy resolution remained at approximately 2.7 keV for low energies, and increased slightly at 45 keV. The average charge-sharing fraction was estimated to be 36% within the investigated energy range of 20-45 keV. The simulated detector output based on the proposed response function agreed well with the experimental measurement. The performance of a spectral imaging system using energy-resolved photon-counting detectors is very dependent on the energy calibration of the detector. The proposed x-ray fluorescence technique offers an accurate and efficient way to calibrate the energy response of a photon-counting detector.

Difusividade e condutividade hidráulica não saturada de substratos

A quantificação dos processos hidráulicos que ocorrem dentro do recipiente durante e entre irrigações, é essencial para a gestão eficaz da irrigação e adubação em substratos. Os testes foram feitos no laboratório de hidráulica da Universidade Federal de Lavras com o objetivo de determinar a condutividade hidráulica não saturada de substratos usando-se o método proposto por Bruce &amp; Klute (1956) em seis substratos (S1, S2, S3, S4, S5 e S6) com quatro repetições. Foram realizados ensaios de fluxo horizontal visando estimar a difusividade e, por seu meio, a condutividade hidráulica não saturada (K(θ)). A taxa com que a umidade avança no espaço e no tempo ocorre de maneira diferenciada entre os substratos avaliados destacando-se os substratos S5 (casca de pinus, vermiculita e turfa) e S2 (cinza, turfa e outros materiais), que tiveram menor e maior difusividade, respectivamente. Após o aumento da tensão ocorre uma nítida diminuição da K(θ), especialmente no substrato S3 (casca de pinus e terra vegetal) enquanto para o substrato S5 os valores foram tão pequenos que não se destacam dentre os demais. A condutividade hidráulica não saturada aumenta com o aumento da umidade, de forma exponencial.

Evaluation of the Influence of Fossil Fuel on Corrosion Resistance of Brass

Brass is an excellent material choice for use in most industrial and agricultural application. Brass offers much better thermal conductivity and corrosion resistance than carbon or even stainless steel. Brass is an excellent material for use in both hot and cold water industrial and residential system including those carrying portable water. This study was carried out to investigate and evaluate the influence of fossil fuel like petrol, kerosene and diesel on the corrosion performance of brass. The samples were prepared for the study by cutting brass into 1 cm2 coupons and soaking them in different small plastic containers containing petrol, kerosene and diesel. The corrosion rate of each sample for a specific period of immersion (120, 240, 360, and 480, 600 and 720 hours) was determined on average of three samples exposed under the same condition and test media in different container. The finding showed that brass is resistant to corrosion after long hours of contact in chosen liquid fossil fuels. Brass has the highest corrosion rate in petrol, followed by kerosene and least in diesel. The photomicrographs of the samples after ten days of immersion also confirmed this.

Optimization of a Trap for Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) and Trials to Determine the Effectiveness of Mass Trapping

Management of the South American tomato leafminer, Tuta absoluta Meyrick, with insecticides has led to the widespread development of insect resistance. Mass trapping using traps baited with the female-produced sex pheromone is an attractive alternative for the management of this pest. The current study evaluated several commercial trap designs for capture of T. absoluta. Based on its small size and ease of handling, the most effective trap is a small plastic container with entry windows cut on the sides filled with motor oil over water. These traps are most effective when placed near ground level. Tests of septa containing 0.1 or 0.2mg of the pheromone (95:5) E4, Z8-14Ac/E4,Z8,Z11-14Ac were slightly more attractive than septa loaded with 0.5, 1.0, or 2mg during the first week of use, but the latter three loadings were slightly more attractive than the first two loadings after 9weeks. Ideal trap baits were loaded with 0.5mg of pheromone. Higher numbers of T. absoluta were captured near upwind borders of tomato fields suggesting that treatments against T. absoluta should be concentrated near upwind parts of fields. Comparisons of conventional insecticide treatment versus mass trapping to manage T. absoluta damage in three different test sites showed that even when initial captures in monitoring traps were high (>35 malestrap(-1)day(-1)), mass trapping at 48 traps/ha reduced leaf damage more efficiently than conventional insecticide treatment. Based on the typical insecticide recommendations against T. absoluta, mass trapping is an economically viable alternative.

Development of an assay to evaluate differences in germination rate among chickpea genotypes under limited water content.

An assay system that provides rapid and reproducible germination under low soil water content (<10% water holding capacity (WHC)) was developed and used to compare how chickpea (Cicer arietinum L.) genotypes complete germination, without the technical difficulties of accurately controlling water levels. The system consisted of small plastic containers (50mm×50mm×60mm) filled with river sand and tightly closed (but not sealed) to minimise water loss and maintain constant soil water content during germination. Seed size influenced germination performance at low WHC. Small seeds within a single genotype germinated successfully and entered into the early stages of seedling growth, but germination of large seeds was inhibited, failing to germinate at 5% WHC. Small seeds were more efficient in remobilising seed reserves to seedling tissues than larger seeds. Under optimal WHC, the germination rate and subsequent radicle growth was similar among genotypes but at low WHC, there was variation despite seeds being of comparable size and imbibing equally. This suggests that the physiological threshold of threshold water potential for initiation of germination reflects genotypic differences. The assay system provides a suitable experimental tool to examine gene expression in contrasting genotypes during germination and early stages of seedling growth with a view to identifying the genes involved in superior performance under water limited field conditions.

A Carbon Dioxide Fatality from Dry Ice

This report documents a rare case of carbon dioxide intoxication in a young healthy male. The deceased hid in a small plastic container, size 1.5 x 1 x 1 m, and within 5 min he was located suffering convulsions and was reported as dead within minutes. Scene investigation revealed dry ice in the container. Autopsy findings were unremarkable. The probable cause of the convulsions was carbon dioxide intoxication due to both the dry ice sublimation and the small confined space in which he was hiding. This report emphasizes the significance of scene investigation in establishing the cause of the death.

Infestation by Aedes albopictus (skuse) in natural and artificial breeding sites found in green areas in the city of Fortaleza, Ceará

Aedes albopictus mosquito is a vector of several different arboviruses and uses natural breeding sites for its reproduction. The objective of this study was to describe the determinants of Aedes albopictus infestation in verdant areas of Fortaleza, Ceara (Brazil). It is a descriptive, exploratory study conducted in four city areas with high vegetation density and presence of natural breeding sites. The environmental, populational and physical aspects of these areas were detailed as well as the possibility that they serve as a source of protection for viable eggs in the dry season. The study was composed of two parts carried out throughout 2007. The first was undertaken during the rainy season with water samples obtained from natural and artificial breeding sites. The second took place in the dry season and samples were collected only from the natural breeding sites. These areas were classified in accordance with the literature and correlated with the presence of immature forms of Aedes albopictus. During the rainy period, of the 62 breeding areas in existence, 49 (79%) were natural and of these, 25 (51%) were infested with Aedes albopictus. Among the trees that tested positively in these areas, the genera Terminalia, Acacia, Bambusa and Magnifera stood out, while in the artificial breeding sites tires, opened coconuts and small plastic containers were most common. Aedes albopictus was the lone inhabitant of 24 (96%) of the natural breeding sites and the greatest density of larvae was found in areas of lesser vegetation and closer to the soil, whereas tires held the higher density within the artificial areas. Nine (37.5%) natural breeding sites continued to be infested in the two seasons and five others only in the rainy season (14; 30.4%; CI 95%: 16.62-44.25). In general terms, there was infestation of 51.0% of natural breeding only in the rainy season, 30.4% only in the dry season and 63.8% if considered in totality. One can conclude that trees of several genera in natural breeding areas offer adequate conditions for the development of immature forms of Aedes albopictus in several stages. In this sense, there may be expanded propagation in the next rainy season in the urban areas of Fortaleza. This scenario amplifies the challenges inherent in the control of dengue fever and other infectious diseases transmitted by this vector.

Suppressed Leaf Senescence in Chrysanthemum Transformed with a Mutated Ethylene Receptor GenemDG-ERS1(etr1-4)

Previously, Narumi et al. (2005) generated chrysanthemum plants transformed with a mutated ethylene receptor gene (mDG-ERS1(etr1-4<), and showed that thein vitro plantlets of the transformants grown aseptically in a small plastic container had a reduced sensitivity to ethylene resulting in reduced leaf yellowing after exposure to exogenous ethylene. In the present study we evaluated ethylene sensitivity of the transformants using soil-grown mature plants. When the shoots detached from soil-grown plants were treated with exogenous ethylene under continuous light, leaf yellowing (senescence) was delayed in the transformants as compared with the non-transformed plants. Furthermore, when the detached shoots were kept in darkness without ethylene treatment, the transformants showed reduced senescence as compared with those of the non-transformed plants. These results demonstrated that the mutated ethylene receptor genemDG-ERS1(etr1-4) could confer reduced sensitivity to ethylene in the leaves of mature chrysanthemum plants. This gene may be useful to generate transgenicCompositae vegetables with leaves green for a longer time and thus having a longer shelf life.

Bacterial endospore inactivation caused by outgassing of vapourous hydrogen peroxide from polymethyl methacrylate (Plexiglas®)

To investigate the cause and to eliminate the inactivation of Bacillus anthracis strain Sterne spores settled onto agar and stainless steel surfaces in plastic holders. In an experimental chamber in which spores settled onto sampling surfaces, vapourous hydrogen peroxide (VHP) was used for decontamination between experiments. It was demonstrated that hydrogen peroxide (H(2)O(2)) absorbed into plastic (Plexiglas) surfaces and could outgas in the sample holders. Further experiments demonstrated that H(2)O(2) was released from Plexiglas sample holders in sufficient quantity to inactivate spores. High temperature degassing (30-35 degrees C) for several days or aluminum coating of the surfaces were two remedies found to be effective in preventing inadvertent spore inactivation. H(2)O(2) can be absorbed into plastic and released after an extended period of time (weeks), allowing a sufficient concentration to accumulate in small volumes to inactivate spores. Outgassing the plastic or coating the surface with an impermeable layer are potential solutions to reduce spore inactivation. Many studies with bacilli and other organisms are carried out using small plastic containers that may have been sterilized using H(2)O(2) or other agents. This study presents a cautionary note to ensure elimination of H(2)O(2) or other sterilizing agents to prevent spurious results.

Chemical control of Nysius natalensis Evans (Hemiptera: Orsillidae), a pest of sunflower in South Africa

No insecticide is currently registered for Nysius natalensis Evans (Hemiptera: Orsillidae), control on sunflower [Helianthus annuus L. (Asteraceae)]. Field as well as laboratory trials were conducted to evaluate efficacy of insecticides for N. natalensis control. During budding prior to anthesis, insecticides were applied aerially. These were endosulfan, a mixture of dichlorvos + monocrotophos, mevinphos, a mixture of endosulfan + cypermethrin, methomyl and cypermethrin Compared to the untreated control, all insecticides provided effective control of N. natalensis. However, re-infestation by the pest occurred in all treatments after five days. A laboratory evaluation of the efficacy of the contact action of eleven insecticides in controlling N. natalensis adults on sunflower heads during application or immediately thereafter was conducted. Insecticides were representative of different groups and modes of action. These were carbosulfan, methomyl, endosulfan, demeton-S-methyl, dichlorvos, chlorpyrifos, malathion, profenofos, cypermethrin, fenvalerate and tau-fluvalinate. The insecticides were applied to sunflower heads containing 50 N. natalensis adults in plastic containers. All insecticides controlled N. natalensis effectively. The efficacy of the eleven insecticides against N. natalensis adults that re-infest sprayed fields from three hours post-application onward, were also evaluated. The insecticides were applied as full cover sprays to sunflower plants in the field. Disks were cut from the leaves three hours after treatment and placed in small plastic containers. Adults were transferred to the treated leaves and evaluated against those on leaves treated with water only. Fenvalerate and tau-fluvalinate were less effective in controlling N. natalensis than the other insecticides evaluated. Reduction in efficacy of seven of the insecticides was evaluated over a period of 14 days. Systemic insecticides remained more effective over longer periods than contact insecticides. However, the contact action of endosulfan remained as effective as the systemic insecticide, demeton-S-methyl. Endosulfan has a low toxicity to bees and will therefore control N. natalensis without a detrimental effect on pollination. To limit the number of applications, correct timing of insecticide application is important. The period that sunflower heads take to turn downward after completion of anthesis will determine the period for application of insecticides against N. natalensis during seed fill.

Photoacoustics as a tool for the diagnosis of radicular stress: Measurements in eucalyptus seedlings

In reforesting companies (cellulose industry), eucalyptus is usually cultivated in small plastic containers (50 mL). As seedlings remain for about 120 days in these containers—until transplantation—their roots become space restricted, with consequent limitations in water and nutrient absorption. These restrictions may lead to plant stress, decreasing productivity. In this work, we used the photoacoustic technique to evaluate the photosynthetic activity of Eucalyptus grandis, E. urophylla and E. urograndis seedlings subjected to this limited space availability, seeking a correlation with morphological parameters and fluorescence measurements in these seedlings. Photoacoustic, fluorescence, and morphological analysis were conducted every 15 days, from 45 to 120 days after sowing. Fluorescence and photosynthetic rate were evaluated in vivo and in situ, the latter one using the open photoacoustic technique. Data show that root dry matter diminished markedly at 90 and 120 days after sowing; this behavior showed a high correlation with the gas exchange component of the photoacoustic signal, as well as with the fluorescence ratio Fv/Fm. These results indicate that the soil volume of the container becomes insufficient for the roots after 90 days, probably leading to a nutritional deficiency in plants, which explains the decrease observed in the photosynthetic rate of seedlings.