Mean Longevity Research Articles

ESTIMATES OF LENGTH-BASED POPULATION PARAMETERS OF SKIPJACK TUNA (KATSUWONUS PELAMIS, LINNAEUS 1798) FROM A POLE & LINE FISHERY IN MAUMERE-SIKKA, INDONESIA

Several population parameters of skipjack tuna (Katsuwonus pelamis) taken by pole and line gear from Maumere Waters from March 2017 to February 2018 were analyzed. A total of 2,194 skipjack tuna was sampled randomly. Fishing activities were carried out around FADs (Fish Aggregating Devices) and free fish shoal. Observers and enumerators collected data from several landing sites and by direct on-board observations. This study aims to provide length-frequency distribution by season, estimate growth mortality parameters, and estimate stock exploitation rate using FISAT software. The results showed that the total catch was dominated by skipjack tuna; up to 80% with the CPUE of 30.8 kg/person/trip, and the skipjack tuna’s length distribution ranged from 26 to 69 cm FL. Length at first capture (Lc) was 34.71 cm FL, and immature fish dominated the total catch with 53%, indicating growth overfishing. The calculated von Bertalanffy growth (VBG) parameters were L= 70.35 cm, K = 0.55 yr-1, and t0 = -0.39 yr. Natural mortality (M) was estimated to be 0.92 and fishing mortality (F) was 0.91. The mean longevity of skipjack tuna is estimated to be 3.2 years, with an exploitation rate (E) of 0.50. Sustainable exploitation of skipjack tuna determined from this analysis could be developed with an Emax of 0.73. There is a focus on reducing the catch of immature fish through various methods that include changing the fishing target area from FADs to fishing on natural fish schools and using gear modifications such as larger-sized (lower number) hooks.

Ventriculosubgaleal shunt and neuroendoscopic lavage: refining the treatment algorithm of neonatal post-hemorrhagic hydrocephalus

BackgroundThe optimal management of neonatal post-hemorrhagic hydrocephalus (PHH) is still debated, though several treatment options have been proposed. In the last years, ventriculosubgaleal shunt (VSgS) and neuroendosdcopic lavage (NEL) have been proposed to overcome the drawbacks of more traditional options, such as external ventricular drainage and ventricular access device.MethodsWe retrospectively reviewed neonates affected by PHH treated at our institution since September 2012 to September 2020. Until 2017 patients received VSgS as initial treatment. After the introduction of NEL, this treatment option was offered to patients with large intraventricular clots. After NEL, VSgS was always placed. Primary VSgS was reserved to patients without significant intraventricular clots and critically ill patients that could not be transferred to the operating room and undergo a longer surgery.ResultsWe collected 63 babies (38 males and 25 females) with mean gestational age of 27.8 ± 3.8SD weeks (range 23–38.5 weeks) and mean birthweight of 1199.7 ± 690.6 SD grams (range 500–3320 g). In 6 patients, hemorrhage occurred in the third trimester of gestation, while in the remaining cases hemorrhage complicated prematurity. This group included 37 inborn and 26 outborn babies. Intraventricular hemorrhage was classified as low grade (I–II according to modified Papile grading scale) in 7 cases, while in the remaining cases the grade of hemorrhage was III to IV. Mean age at first neurosurgical procedure was 32.2 ± 3.6SD weeks (range 25.4–40 weeks). Death due to prematurity occurred in 5 patients. First-line treatment was VSgS in 49 patients and NEL in the remaining 14 cases. Mean longevity of VSgS was 30.3 days (range 10–97 days) in patients finally requiring an additional treatment of hydrocephalus. Thirty-two patients required one to three redo VSgS. Interval from initial treatment to permanent shunt ranged from 14 to 312 days (mean 70.9 days). CSF infection was observed in 5 patients (7.9%). Shunt dependency was observed in 51 out of 58 surviving patients, while 7 cases remained shunt-free at the last follow-up. Multiloculated hydrocephalus was observed in 14 cases. Among these, only one patient initially received NEL and was complicated by isolated trapped temporal horn.ConclusionsVSgS and NEL are two effective treatment options in the management of PHH. Both procedures should be part of the neurosurgical armamentarium to deal with PHH, since they offer specific advantages in selected patients. A treatment algorithm combining these two options may reduce the infectious risk and the risk of multiloculated hydrocephalus.

Effect of temperature on the sex ratio and life table parameters of the leek‐(L1) and tobacco‐associated (T) Thrips tabaci lineages (Thysanoptera: Thripidae)

AbstractTemperature strongly affects insect biological response. Effects of temperature on the sex ratio, preoviposition, fecundity, egg hatchability rate, and adult longevity of the L1 and T Thrips tabaci lineages were studied under laboratory conditions at three constant temperature levels (15, 23, and 30°C) on cabbage and tobacco leaf discs, respectively. Results showed that temperature affects all the tested life table parameters of L1 and T lineages. The proportion of female's log‐linearly increased as temperature increased. Preoviposition period, fecundity, adult longevity, and egg hatchability rate were reduced significantly with increasing temperature. In both lineages, the lowest egg hatchability rates were recorded at 30°C and the highest rates were recorded at 15°C. Mean fecundity of the L1 and T lineages were 107.63 and 84.83 at 23°C, respectively, and mean fecundity of the L1 and T lineages were 19.88 and 70.82 at 15°C, respectively. The lowest mean fecundity was recorded at 15°C and 30°C for the L1 and T lineages, respectively. Mean longevity were 34.22 and 81.82 days at 15°C for L1 and T lineages, respectively. Whereas, the shortest mean longevity (13.63 and 13.91 days) was observed at 30°C for the L1 and T lineages, respectively. Our results demonstrated that 23°C was the optimum temperature for fecundity among the studied temperature levels for the studied population of the L1 and T T. tabaci lineages.

Fluctuating thermal regimes extend longevity and maintain fecundity to increase shelf‐life of Drosophila melanogaster cultures

AbstractReduced temperatures increase longevity in cold‐tolerant insects, but insects that are not cold‐tolerant experience elevated mortality at constant low temperatures. Fluctuating thermal regimes (FTRs) increase longevity in many insect species while slowing or delaying development and senescence. Under FTR insects are held at low temperature with a daily warm pulse of increased temperature. The model organism Drosophila melanogaster is widely used for diverse research activities and numerous transgenic strains have been developed and must be maintained in continuous culture at stock centres. We measured the effect of FTR that oscillates between 6 and 22 °C on the longevity and fertility of adult D. melanogaster versus a constant temperature of 6 and 22 °C. We demonstrate that FTR increases mean longevity by 8.8‐fold compared to a constant 6 °C and by 5.9‐fold to a constant 22 °C. We assessed male and female fertility of FTR treated adults from 20 to 100 days at 20 day intervals and constant temperature treated adults after 7 days. Under FTR males exhibited increased fertility peaking at 80 days before dropping significantly at 100 days. Mean female fertility declined steadily under FTR but remained at 53% of constant temperature‐treated flies after 60 days. The increased male fertility remains unexplained. Fertility of the offspring of FTR‐treated adults did not differ from flies reared at constant 22 °C. FTR extends generations and cultures incubated under this protocol can establish new cultures. FTR can be used to further investigate the accumulation and mitigation of chill injury and is suitable for reducing maintenance in stock centres.

Engineered expression of the invertebrate-specific scorpion toxin AaHIT reduces adult longevity and female fecundity in the diamondback moth Plutella xylostella.

Previous genetic pest management (GPM) systems in diamondback moth (DBM) have relied on expressing lethal proteins ('effectors') that are 'cell-autonomous', that is, they do not leave the cell in which they are expressed. To increase the flexibility of future GPM systems in DBM, we aimed to assess the use of a non-cell-autonomous, invertebrate-specific, neurotoxic effector - the scorpion toxin AaHIT. This AaHIT effector was designed to be secreted by expressing cells, potentially leading to effects on distant cells, specifically neuromuscular junctions. Expression of AaHIT caused a 'shaking/quivering' phenotype that could be repressed by provision of an antidote (tetracycline): a phenotype consistent with the AaHIT mode-of-action. This effect was more pronounced when AaHIT expression was driven by the Hr5/ie1 promoter (82.44% of males, 65.14% of females) rather than Op/ie2 (57.35% of males, 48.39% of females). Contrary to expectations, the shaking phenotype and observed fitness costs were limited to adults in which they caused severe reductions in mean longevity (-81%) and median female fecundity (-93%). Quantitative polymerase chain reactions of AaHIT expression patterns and analysis of piggyBac-mediated transgene insertion sites suggest that restriction of the observed effects to the adult stages may be due to the influence of the local genomic environment on the tetO-AaHIT transgene. We demonstrated the feasibility of using non-cell-autonomous effectors within a GPM context for the first time in Lepidoptera, one of the most economically damaging orders of insects. These findings provide a framework for extending this system to other pest Lepidoptera and to other secreted effectors. © 2021 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Biological control potential of an aphid parasitoid, Diaeretiella rapae (McIntosh) (Hymenoptera: Braconidae) against Brevicoryne brassicae (Linnaeus) (Hemiptera: Aphididae), a pest of oilseed brassicas in India

Biological and behavioural attributes of Diaeretiella rapae (McIntosh) (Hymenoptera: Braconidae) were studied on Brevicoryne brassicae (Linnaeus) (Hemiptera: Aphididae). The total developmental duration of the parasitoid was longer in younger nymphal instars compared to that in older nymphal instars of aphid. Host age affected the oviposition period and fecundity of the ovipositing parasitoid. Survival of the immatures was higher in older as compared to the younger instars. Sex ratio for the parasitoid was found to be female-biased. Adult longevity of D. rapae was longer for females compared to that of males. Mean longevity of adult female parasitoid was longer, while parasitizing nymphs of younger age groups (1–2 days) compared to that of older age groups (4–5 days). B. brassicae reared on cabbage (Brassica oleracea var. capitata) was found to be the best host for D. rapae based on high per cent parasitism and high fecundity. The parasitoid showed a higher preference towards third nymphal instar of B. brassicae both in choice and no-choice tests. The results from experiments on mutual interference revealed that per capita searching efficiency decreased significantly from 0.99 to 0.05 with an increase in parasitoid densities from 1 to 8. Logistic regression exhibited a type II functional response for D. rapae. The handling time (Th) and searching efficiency (a) values were calculated to be 1.35 ± 0.05 h and 0.025865 ± 0.001525 h, respectively. This investigation suggests that D. rapae could be an effective biocontrol agent of B. brassicae that would supplement its management options in oilseed brassicas.

DDSLA-RPL: Dynamic Decision System Based on Learning Automata in the RPL Protocol for Achieving QoS

The internet of things is a worldwide technological development in communications. Low Power and Lossy Networks (LLN) are a fundamental part of the internet of things with numerous monitoring and controlling applications. This network has many challenges as well, due to limited hardware and communication resources, which causes problems in applications such as routing, connections, data transfer, and aggregation between nodes. The IETF group has provided a routing model for LLN networks, which expands IPv6 protocol based on Routing Protocol (RPL). The pro-posed decision system DDSLA-RPL creates a list of limited k member optimal parents based on qualitatively effective parameters such as hop, link quality, SNR rate, and ETX energy consumption, by informing child nodes of their connection link to available parents. In the routing section, a decision system approach based on learning automata has been proposed to dynamically determine and update the weight of influential parameters in routing. The effective parameters in the routing phase of DDSLA-RPL include battery depletion index, connection delay, and node queuing and throughput. The results of the simulation show that the proposed method outperforms other methods by about 30, 17, 20, 18, and 24 percent in mean longevity and energy efficiency, graph sustainability, operational power and latency, packet delivery rate test, and finally number of control messages test, respectively.

Biological and behavioural characteristics of Diaeretiella rapae (McIntosh), a parasitoid of Lipaphis erysimi (Kaltenbach) infesting oilseed brassicas in India

ABSTRACT Biological and behavioural characteristics of Diaeretiella rapae were studied in a laboratory using Lipaphis erysimi as a host. The total developmental period of the parasitoid was longer in early instars as compared to that in later instars. Host age at the time of oviposition affected the oviposition period, post-oviposition period and fecundity of the parasitoid. Survival of the immatures was higher in older than the younger instars. The sex ratio for the parasitoid was found to be female-biased. Adult longevity of D. rapae was longer for females when compared to that of males. The mean longevity of adult females of the parasitoid was longer while parasitizing nymphs of younger age groups (1–2 days) compared to that of older age groups (4–5 days). L. erysimi reared on mustard was found to be the best host for D. rapae based on high parasitisation (%), female-biased sex ratio and the shortest time required by the parasitoid for completion of the total developmental period. The parasitoid showed a higher preference towards second instar nymphs of L. erysimi, both in choice and no-choice tests. The per capita parasitisation and search efficiency of the parasitoid decreased with an increase in parasitoid density. Logistic regression exhibited type-II functional response for the parasitoid D. rapae. Overall, D. rapae appeared to be a potential biocontrol agent of L. erysimi that would supplement its biological control in oilseed brassicas.

Studies on biology of mango leaf webber Orthaga exvinacea (Hampson)

The laboratory studies on biology of mango leaf webber was conducted at the Department of Entomology, College of Horticulture, Bagalkot during 2018-19. The studies revealed that the mean preoviposition, oviposition and postoviposition periods lasted for 2.60±0.52, 4.10±0.74 and 1.90±0.74 days, respectively. The larva moulted six times by passing through seven larval instars. The mean durations of 1st, 2nd, 3rd, 4th, 5th, 6th and 7th instar were 4.80±0.92, 4.65±0.90, 4.41±0.63, 4.16±0.87, 4.52±0.51, 5.20±0.42 and 6.50±0.53 days, respectively with mean total larval period of 42.54±2.53 days. The mean duration of male and female pupal stage were 11.80±0.63 days and 14.30±1.43 days respectively. The mean longevity of adult male and female were 4.10±0.74 days and 5.80±0.42 days, respectively. The total life cycle completed in 58.44±3.90days in male and 62.64±4.59 days in female.

Longevity in a hunted population of reintroduced American bison (Bison bison)

Mean and maximum longevity (i.e., age-at-death) in free-ranging American bison (Bison bison) subject to natural selection is difficult to estimate in the wild; hence, data on age-at-death for free-ranging populations is sparse. I used a 20-year time series of age-at-death data from 1909 bison to estimate mean longevity of hunter-killed bison in a growing population. I tested the following predictions: (a) mean longevity of hunted females was greater than males, (b) mean longevity for hunted animals was less than those dying from natural causes, and (c) longevity did not respond to increasing population size (i.e., density independence). In support of my prediction, mean age-at-death of females (6.3 ± 3.8 (SD) years old) was greater than that for males (5.3 ± 2.7 years old); however, the difference was only 1 year. Most bison (45%) died as mature adults (4–7 years old), and few lived to become dominant or aged adults, which may have important implications for social ecology or population dynamics. Maximum longevity (i.e., oldest age-at-death) was 22 and 25 years old for males and females, respectively. The mean age-at-death of hunted females was 1.4 years younger than a small sample that died of natural causes. Contrary to my prediction, longevity increased slightly for females, but not males, with an increase in abundance. These data may be useful for better understanding bison demography and life history strategies, as well as parameterizing population models, particularly for hunted populations. Similar data from unhunted populations subject to natural selection would be informative to test the generality of these findings.

A Retrospective Analysis of Results and Outcomes after Cadence Total Ankle Arthroplasty Implanted through the End of 2017

Category:Ankle; Ankle ArthritisIntroduction/Purpose:Total ankle arthroplasty (TAA) is an increasingly popular operative treatment of ankle arthritis, due to its ability to decrease adjacent joint degeneration and preserve gait mechanics compared to ankle arthrodesis. However, ankle arthroplasty components have a shorter mean longevity then their hip, knee, or shoulder counterparts. The Cadence TAA entered clinical use in 2016 and was designed to address common failure modes of prior systems. We report here on radiographic and clinical outcomes and early complications of the Cadence TAA system at a minimum of 2 years follow-up.Methods:Patients who underwent primary Cadence TAA from 2016 through 2017 by one fellowship-trained foot and ankle surgeon were eligible. Exclusion criteria included prior ipsilateral ankle arthrodesis or arthroplasty and lack of followup. Chart review was performed for eligible patients to identify complications and reoperations. Patients were contacted to obtain Foot and Ankle Ability Measure (FAAM) Activities of Daily Living (ADL) and Sport subscores, SF-12 Mental (MCS) and Physical Health (PCS) subscores, and Visual Analog Scale (VAS) pain levels (rated 0-100). Scores were analyzed with 2-sided repeated measures T- tests, with P<0.05 as significant. A second, blinded, fellowship-trained foot and ankle surgeon evaluated followup 5-view radiographs of each ankle to measure range of motion (ROM), alignment, peri-implant osteolysis, and component loosening or subsidence. Subsidence or loosening were defined, respectively, as >2mm or >2⁰ change in position for the tibial component and>5mm or >5⁰ change for the talar component.Results:Sixty patients were included with mean age 64 and mean BMI 32.0. Thirty patients (50%) had concurrent other procedure(s). FAAM-ADL, FAAM-Sports, SF-12 PCS, and VAS pain scores all improved significantly at mean 2.24 years post-op (Table 1). Ten patients (6.7%) had operative complications requiring 15 surgeries (mean 265 days to first reoperation). Three patients (5%) required removal of one or both components, for 2-year implant survival of 95.0%. Two revisions were for infection and one for osteolysis. This produced a mechanical failure rate of 1/60 (1.7%). Radiographic analysis revealed average coronal alignment improved from 7.4⁰ from neutral preoperatively to 2.2⁰ postoperatively. Average ROM was 36.5⁰ total arc of motion.One of 38 (2.6%) had signs of peri-implant osteolysis, with no cases demonstrating loosening or subsidence.Conclusion:Two-year follow-up of the Cadence TAA system demonstrates mechanically stable implants resulting in improved patient function and preserved ankle range of motion. Outcomes compare favorably to those of other TAA systems at 2-year follow-up. Further radiographic and clinical follow-up are needed to evaluate implant longevity and long-term patient functional outcomes.

Development, reproduction and life table parameters of Tetranychus turkestani (Acari: Tetranychidae) on three different host plants

The strawberry spider mite, Tetranychus turkestani Ugarov and Nikolski, is one of the most important pests of different field and glasshouse crops in Iran. The objectives of the current study were to determine developmental time, survival, reproduction and life table parameters of T. turkestani on three plant species: cowpea (Vigna unguiculata L.), white bean (Phaseolus lunatus L.) and red bean (Phaseolus calcaratus Roxb.) at 25 ± 1 °C, 60 ± 10 % RH and a photoperiod of 16:8 (L:D). The mean developmental time from egg to adult on cowpea, white bean and red bean were 11.99, 10.43 and 10.46 days, respectively. The total preadult survival rates varied from 75% to 80%. Females of T. turkestani oviposited means of 65.13, 44.03 and 32.69 eggs on cowpea, white bean and red bean, respectively, and had a mean longevity of 13.92, 9.08 and 7.23 days on the same three host plants. The intrinsic rate of increase (rm) varied from 0.18 to 0.21. The net reproductive rate (R0) was higher on cowpea (42.33) than on white bean (24.95) or red bean (14.16). Using these measures, T. turkestani performance was best on cowpea, worst on red bean, and intermediate on white bean.

Sublethal effects of emamectin benzoate on life table parameters of the cotton leafworm, Spodoptera littoralis (Boisd.)

BackgroundThe cotton leafworm, Spodoptera littoralis (Boisd.), is a serious economic pest in Egypt. Pest control depends mainly on chemical control with several pesticides include conventional and modern insecticides. Comprehensive analysis of pesticides impacts needs to investigate sublethal effects in addition to lethal effect.ResultsIn the current study, the leaf-dip bioassay method was used to evaluate emamectin benzoate (EMB) sublethal concentrations. Results showed that EMB proved high toxicity against S. littorals with LC50 value of 0.019 mg liter−1. Life table analysis showed that treatments with LC5 and LC15 prolonged larval period, mean longevity of males and females, mean generation time (T), doubling time (DT), adult preovipositional period (APOP), and total preovipositional period (TPOP) compared with control. On the contrary, net reproduction rates (R0), intrinsic rates of increase (r), finite rate (λ), fecundity, gross reproductive rate (GRR), and relative fitness were decreased compared to control.ConclusionsThe current study clarified that sublethal concentrations of EMB induce adverse effects and suppress the population growth of S. littorals. Our results would be useful to assess the overall effects of EMB on S. littorals and can contribute effectively in pest management.

Fertility life table and biology of Tetrastichus giffardianus (Hymenoptera: Eulophidae) in the larvae of Ceratitis capitata (Diptera: Tephritidae).

Tetrastichus giffardianus is a gregarious koinobiont endoparasitoid of tephritids, including Ceratitis capitata, which is one of the most important fruit pests worldwide. The objective of this study was to evaluate the effect of constant temperatures on the biology and development of the egg-adult period of T. giffardianus in larvae/pupae of C. capitata to construct a fertility life table. The study was carried out in climatic chambers at constant temperatures of 15, 20, 25, 30, and 35 ± 1°C, 70 ± 10% relative humidity and a photophase of 12 h. Complete egg and larval development occurred only at temperatures of 20, 25, and 30°C. The mean longevity of males and females was inversely proportional to temperature. The time of development of the pre-imaginal period was influenced by temperature and ranged from 41 days at 20°C to 11 days at 25°C. The best T. giffardianus performance occurred at 25°C when the intrinsic rate of increase was 0.21, the mean generation time was 20.43 days, the time required to double the population was 3.33 days, and the finite rate of population increase (λ) was 1.23. The results of this study provided information for the establishment of mass rearing and an evaluation of the adaptability of T. giffardianus to different environments, which is necessary for the use of this parasitoid in the biological control of tephritid pests, particularly C. capitata.

A retrospective analysis of mortality in captive Magellanic penguins (Spheniscus magellanicus) in the United States, 2008-2018.

Mortality data for Magellanic penguins (Spheniscus magellanicus) housed in zoos and aquariums in the United States has not previously been published. Necropsy and histopathology records were examined for Magellanic penguins housed at 12 Association of Zoos and Aquariums institutions from 2008 through 2018. If birds lived through the first year, the mean longevity was found to be 18.9 years of age (standard deviation: 7.9). Prefledge chicks and geriatric penguins experienced the highest mortality rates. Aspergillosis was a major cause of death in this species. There was no significant difference in mortality between males and females. Based on these data, recommendations for the husbandry and veterinary care of captive Magellanic penguins can be made.

Biology of anthocorid predator, Blaptostethus pallescens Poppius (Heteroptera: Anthocoridae)

Biology of anthocorid predator Blaptostethus pallescens Poppius was studied on eggs of alternate host Corcyra cephalonica (Stainton). Eggs of B. pallescens, thrust within the plant tissue, hatched after a mean incubation period of 5.78 days. Nymphs, when reared on UV sterilized eggs of C. cephalonica under ambient conditions, developed normally with five instars, each having a mean duration of 2.63, 1.92, 2.01, 2.50 and 5.10 days, respectively. Females laid eggs after a pre-oviposition period of 4.2 days. Average fecundity of bugs was 134.04 eggs. Mean longevity of females was found to be higher (52.03 days) than that of males (40.18 days).

Predicting death by the loss of intestinal function.

The ability to predict when an individual will die can be extremely useful for many research problems in aging. A technique for predicting death in the model organism, Drosophila melanogaster, has been proposed which relies on an increase in the permeability of the fly intestinal system, allowing dyes from the diet to permeate the body of the fly shortly before death. In this study we sought to verify this claim in a large cohort study using different populations of D. melanogaster and different dyes. We found that only about 50% of the individuals showed a visible distribution of dye before death. This number did not vary substantially with the dye used. Most flies that did turn a blue color before death did so within 24 hours of death. There was also a measurable effect of the dye on the fly mean longevity. These results would tend to limit the utility of this method depending on the application the method was intended for.

Biological Studies and Estimation Life Table Parameters of Chrysanthemum Aphid, Macrosiphoniella sanborni under Different Temperature Conditions

This study was carried out to study the biology and life table parameters of Chrysanthemum aphid, Macrosiphoniella sanborni under laboratory conditions throughout three different temperatures degrees (winter, spring, and summer) during the 2018 year. Data obtained showed that the spring season more suitable for M. sanborni living (biology) more than winter and summer seasons, respectively. This showed clearly from the life table's parameters, which showed that the nymphal stages of M. sanborni in spring season were less than in winter and summer, respectively. Also, the life cycle, mean generation time, life span and longevity duration in spring season were less than in winter and summer seasons respectively. Lastly, the important parameter in the life table, intrinsic rate of increase (rm) in spring season was more than in winter and summer seasons, respectively.

The Impact of Insecticide-treated Bed Nets on Parity and Malaria Sporozoite Infectivity of Anopheles Species in Kamuli District, Uganda

Background: The main objective of treating bed nets with insecticides is to affect the mean longevity of the main vector population, and consequently the vector density and sporozoite rates.&#x0D; Objective: This study aimed at establishing the impact of insecticide-treated bed nets (ITNs) on the longevity and ability to transmit malaria sporozoites by the vector species as an assessment of effectiveness of the ITN intervention in Kamuli district, Uganda.&#x0D; Methods: Indoor human-biting mosquitoes were trapped in three randomly selected houses in two separate nights using battery-operated CDC light traps in both intervention (with ITNs) and non-intervention villages (without ITNs). The female anophelines were dissected and their parity rates and Plasmodium falciparum sporozoite positivity compared between the two zones. A sporozoite Enzyme-Linked Immuno Sorbent Assay, ELISA, was used to detect the presence of P. falciparum sporozoites in the parous vectors in both zones.&#x0D; The parity and P. falciparum sporozoite infectivity were compared between the two zones using the Kruskal-Wallis rank sum test of the R-Statistics software.&#x0D; Results: Out of the 166 Anopheles mosquitoes dissected, 37.3% (19 out of 51) and 53.9% (62 out of 115) were parous in the intervention and non-intervention zones, respectively, indicating that parity of the mosquitoes was higher in the non-intervention (p = 0.005). Infectivity of the vectors in the non-intervention exceeded that in the intervention zone (p = 0.032), with active sporozoite transmission observed before and after bed time in the non-intervention zone.&#x0D; Conclusion: Results showed that ITNs had impacted on the survival and consequently the density of the older malaria vectors, and on their ability to transmit Plasmodium sporozoites. This calls for intensification of use of this effective malaria control strategy, coupled with behavioural change communications strategy to promote correct use, as well as use of other interventions like repellents to provide additional protection especially before and after bed time.

The role of cement service-life on the efficient use of resources

The high demand for cement-based materials to support building and infrastructure systems is of growing concern as the production of cement leads to significant greenhouse gas (GHG) emissions and notable resource demand. While improved efficiency of cement use has been proposed as a means to mitigate these burdens, the effects of increasing longevity of cement in-use remains a poorly studied area. This work quantitatively explores the implications of using cement for a longer in-use residence times. Specifically, this work uses dynamic material flow analysis models to quantify the in-use stock of cement in the United States from 1900 to 2015. With these models, the implications of increasing or decreasing mean longevity of in-use cement on required cement production, demand for batching water, aggregates, and energy for cement-based materials, and GHG emissions are quantified. This work shows that a 50% increase in cement longevity could have led to a 14% reduction in material resource demand and GHG emissions from concrete production in the United States, equivalent to 0.28 to 0.83 Gt of batching water, 2.9 to 7.6 Gt of aggregates, 1E + 06 to 2.3E + 06 TJ of energy, and 0.4 to 0.7 Gt of CO2-eq emissions. This percent reduction exceeds goals for reducing GHG emissions through alternative energy resources, suggesting improving durability and longevity of in-use cement stock could be a critical means to mitigating environmental impacts.