Environmental change and the chemical record in Loch Lomond sediments

The chemical record in Loch Lomond sediments deposited since the end of the last Ice Age provides evidence of the Flandrian marine transgression some 5500–7000 ¹⁴C years B.P., sedimentation rates and the influence of man's local activities, environmental pollution and its sources since the onset of the Industrial Revolution, and of elemental mobility linked with the reduction-diffusion-oxidation cycle of early sedimentary diagenesis. Information derived from vertical profiles of halogen elements bromine and iodine, radionuclides ¹⁴C and ²¹⁰Pb, heavy metals lead, zinc, and cadmium, stable lead isotopes ²⁰⁶Pb and ²⁰⁷Pb, and redox-sensitive elements manganese, iron and arsenic is reviewed and assessed.     

Late Quaternary deep and surface water mass evolution in the northeastern Indian Ocean inferred from carbon and oxygen isotopes of benthic and planktonic foraminifera

New planktonic and benthic foraminiferal stable isotope records from core YDY05 (northeastern Indian Ocean) provide new insights into paleoceanographic changes in the northeastern Indian Ocean since the last glacial period. The distinct δ¹⁸O decrease was observed since the beginning of the deglaciation to the mid-Holocene (∼8–6 kyr BP), possibly reflecting a reduction in surface salinity in the central Bay of Bengal (BoB) water, which probably resulted from strengthened precipitation, concurrent enhanced river discharge and rising sea-level, related to the intensification of Indian Summer Monsoon (ISM). Variations in benthic δ¹³C and δ¹³C_{Planktonic-Benthic} in our core site reflect significant variations in source water characteristics over the LGM-Holocene. The large δ¹³C_{Planktonic-Benthic} offset during the glacial period suggests a more sluggish deep water circulation, and lower δ¹³C_{Planktonic-Benthic} from the deglaciation to the Holocene suggests an enhanced deep water circulation in the central BoB. The drastic depletion in benthic δ¹³C during the glacial period suggests a significant reduction of North Atlantic Deep Water (NADW) intrusion and a progressive influx of Antarctic Bottom Water (AABW) and ¹²C-rich Circumpolar Deep Water (CDW) into the central BoB. In contrast, since the deglaciation, the central BoB experienced a drastically increased intrusion of better ventilated and ¹³C-rich NADW. The differences in benthic δ¹⁸O between the LGM section and the Holocene exceeds the ice volume effect by ∼0.5‰, providing further evidence that the deep water mass of the central BoB was influenced by the less dense NADW, instead of the AABW, since the last deglaciation.     

Twentieth anniversary of Homo antecessor (1997‐2017): a review

It has been twenty years since diagnosis and publication of the species Homo antecessor.¹ Since then, new human fossils recovered from the TD6 level of the Gran Dolina site (Sierra de Atapuerca, northern Spain) have helped to refine its taxonomic and phylogenetic position. In this paper, we present a synthesis of the most characteristic features of this species, as well as our interpretation derived from the latest investigations. We focus on the phylogenetic interpretation of Homo antecessor, taking into account the most recent paleogenetic analyses and a reassessment of the European Middle Pleistocene hominin record. We try to show that, twenty years after its publication, H. antecessor provides a good opportunity to address the morphology of the last common ancestor of Neandertals and modern humans.     

Trace elements influenced by environmental changes in Lake Biwa: (II) Chemical variations in the hypolimnion over the last half-century

The history of the deep north basin of Lake Biwa extends over 430,000 years. Although it has probably been oxic and oligotrophic since its formation, human impacts have been changing lake conditions. In this paper, we discuss long-term changes in the chemistry of bottom water by compiling literature and through our own data over the last half-century. Long-term records show an increase in temperature, decrease in dissolved oxygen (DO), and increase in nutrients in bottom water. The stoichiometry among oxygen and nutrients indicates that changes are basically consistent with aerobic decomposition of organic matter. These changes are most likely the result of global warming and local eutrophication. Of particular note, yearly minimum DO concentrations <50 µmol kg^?1 have started to occur frequently at ~90 m depth since 1999. Manganese (Mn) concentrations in bottom water are at their minimum during the turnover period and at a maximum during the late stratification period each year. Yearly minimum Mn concentration has been within a narrow range over the last 30 years (0.25 ± 0.07 µmol kg^?1, n = 12). However, abnormally high Mn concentrations (up to 9.3 µmol kg^?1) were observed in 2007, caused by reductive release of a substantial amount of Mn from suboxic sediments and subsequent oxidation in bottom water. The concentration of arsenic (As) has gradually increased over the last 20 years in a similar manner, with a homologous element of phosphorus (P), resulting in an observed range of 17–29 nmol kg^?1 in 2010. The accumulation rate was ~0.8 nmol kg^?1 year^?1 for As and ~6 nmol kg^?1 year^?1 for P.     

Proteomics Data Collection – 4th ProDaC Workshop 15 August 2008, Amsterdam,The Netherlands

ProDaC (Proteomics Data Collection), a “Coordination Action” within the 6^th EU framework programme, was created to support the collection, distribution and public availability of data from proteomics experiments. Within the consortium standards are created and maintained enabling an extensive data collection within the proteomics community. Important elements of ProDaC are workshops held twice a year to allow communication between the ProDaC partners and to report the ongoing progress. The most recent assembly was the 4^th ProDaC workshop on August 15^th, 2008, in Amsterdam, The Netherlands. It took place directly before the 7^th HUPO Annual World Congress (Human Proteome Organisation). Work package coordinators and partners presented the progress achieved since the last meeting. Additionally, an EU official presented funding opportunities for proteomics in the next EU framework programme and five external speakers presented talks about their work in relation to ProDaC.     

A late quarternary lake in the central Namib desert,Southern Africa,and some implications

Lake bed carbonates from Narabeb in the central Namib Desert have been dated by the ²³⁴U/²³⁰Th method at between 210 000 and 240 000 years. Their survival on the ground surface implies that the climate has been arid since this time, and this is interpreted as confirming the hypothesis that the Benguela Current has maintained its influence over the climate of this area throughout the last two glacials.     

Growth decline of Pinus Massoniana in response to warming induced drought and increasing intrinsic water use efficiency in humid subtropical China

Pinus Massoniana is the most widely distributed coniferous species in southern China and one of the most distributed species for plantation in China. It is not uncertain about the responses of tree growth to the combined effects of regional drying and the increase in the intrinsic water-use efficiency (iWUE) due to increased atmospheric CO₂. This study addressed this issue by comparing the tree growth patterns as represented by three tree-ring width chronologies with climate variables and three iWUE series derived from three tree-ring stable carbon isotope discrimination chronologies (Δ¹³C) from Pinus Massoniana in Daiyun Mountain, central Fujian province of China. Among these chronologies, we reported the first tree-ring carbon isotope discrimination chronologies (Δ¹³C) from Fuzhou area spanning last 210 years. It was found that tree radial growth is mainly limited by dry condition from May to October. Growth limitation by cold condition was only found in one high altitude site (780m) in early spring and late autumn. The tree-ring carbon discrimination was enhanced under conditions with low relative humidity and sufficient sunshine in late summer and autumn. In general, the iWUE showed a significantly increasing trend since the 1850s for all the sites in response to the increase in atmospheric CO₂. However, the growth promotion of the increased iWUE on tree growth could not compensate the growth limitation caused by drought. Especially since the 1960s, a growth decline was found at two drought stressed sites at low altitudes. On the other hand, the increase in temperature of spring and autumn and iWUE has most likely enhanced tree growth at the high altitude site.     

Synchronous division induced in Escherichia coli K12 by gemts mutants of phage Mu

Summary Infection with the bacteriophage mutant Mu c ⁺ gemts2 at 42° C induces synchrony in cell division in cultures of Escherichia coli K12. This synchrony may last for several cycles and is not only due to selection since synchronization is observed even when bacterial survival to the infection is over 80% as in lysogens for Mu c ⁺ gemts2. The mechanism by which sycnhrony is induced is not known, but since the product of Mu gene gem (previously called lig) has been shown to interact with the enzymatic system in the bacteria controlling the degree of DNA supercoiling, the phenomenon could be a consequence of this interaction.     

Fission-track dating in paleoanthropology

During the last 30 years, fission-track dating has become a versatile geochronological tool.¹ Fission-tracks, discovered in the early 1960s,² were subsequently used to determine the age of minerals and glasses.³ Although low track densities can make fission-track dating tedious and time-consuming, the technique can provide important data for material in time ranges as young as the last few million years. In anthropological studies, fission-track dating is most useful for dating burned artifacts and volcanic ashes intercalated with hominid-bearing layers.     

Long-term trends and variation in <Superscript>137</Superscript>Cs activity concentrations in brown trout (<Emphasis Type="Italic">Salmo trutta</Emphasis>) from Øvre Heimdalsvatn,a Norwegian subalpine lake

The Norwegian mountain lake, Øvre Heimdalsvatn, received major fallout from the Chernobyl accident in the spring of 1986. Activity concentrations of ¹³⁷Cs have been monitored annually in the brown trout (Salmo trutta) population of the lake over a 22-year period since 1986. The activity concentrations of ¹³⁷Cs in brown trout have declined over the period, although in recent years there has been little or no reduction in activity concentrations. Throughout the period, there has been considerable individual variation in ¹³⁷Cs activity concentrations. Within a single year, fish weight was the most significant factor affecting activity concentrations of ¹³⁷Cs in individual fish, although sex and age·weight were significant explanatory variables. The “size effect” was not significant during the initial period after fallout and in some recent years. During the first years after fallout, the ecological half-life of ¹³⁷Cs in brown trout was 3–4 years, but during the last decade this has increased significantly and has approached the physical half-life of 30 years for ¹³⁷Cs, suggesting a dynamic equilibrium between catchments inputs, possible remobilisation from lake sediments and lake outputs of ¹³⁷Cs.     

Metabolic engineering for the optimization of hydrogen production in Escherichia coli: A review

Hydrogen is a potential sustainable energy source and it could become an alternative to fossil fuel combustion, thus helping to reduce greenhouse gas emissions. The biological production of hydrogen, instead of its chemical synthesis, is a promising possibility since this process requires less energy and is more sustainable and eco-friendly. Several microorganisms have been used for this purpose, but Escherichia coli is one of the most widely used in this field. The literature in this area has increased exponentially in the last 10 years and several strategies have been reported in an effort to improve hydrogen production. In this work, the stay of the art of hydrogen biosynthesis by E. coli and metabolic engineering strategies to enhance hydrogen production are reviewed. This work includes a discussion about the hydrogenase complexes responsible for the hydrogen synthesis in this microorganism and the central carbon metabolism pathways connected to this process. The main metabolic engineering strategies applied are discussed, including heterologous gene expression, adaptive evolution and metabolic and protein engineering. On the other hand, culture conditions, including the use of carbon sources such as glycerol, glucose or organic wastes, have also been considered. Yields and productivities of the most relevant engineered strains reported using several carbon sources are also compared.     

Twentieth century changes of tree-ring δ13C at the southern range-edge of Fagus sylvatica: increasing water-use efficiency does not avoid the growth decline induced by warming at low altitudes

We aimed to gain knowledge on the changes in intrinsic water use efficiency (iWUE) in response to increasing atmospheric CO₂ concentrations and climate change over the last century. We investigated the variation in the iWUE of mature Fagus sylvatica trees located in the higher, central and lower altitudinal forest limits (HFL, CFA and LFL) of one of the southernmost sites of beech distribution in Europe, the Montseny Mountains in Catalonia (northeast Spain), during the last century by analysing the δ¹³C of their tree rings. Pre‐ and post‐maturation phases of the trees presented different trends in δ¹³C, Δ¹³C, Ci (internal CO₂ concentration), iWUE and basal area increment (BAI). Moreover, these variables showed different trends and absolute values in the LFL than in the other altitudinal sites, CFA and HFL. Our results show the existence of an age effect on δ¹³C in the CFA and HFL (values increased by ca. 1.25‰ coinciding with the BAI suppression and release phases, previous to maturation). These age‐related changes were not found in the LFL, whose beech trees arrived to maturation earlier and experienced drier conditions during the suppression phase. In the last 26 years of comparable mature trees, the increase of iWUE deduced from the Δ¹³C analyses was ca. 10% in LFL, ca. 6% in CFA and not significant in HFL. These results show that climate change towards more arid conditions accounted for these higher Δ¹³C‐values and increases in the LFL more than the continuous increase in atmospheric CO₂ concentrations. This increased iWUE in the LFL did not avoid a decline in growth in these lowest altitudes of this beech southern range‐edge as a result of warming. Furthermore, since there was no apparent change in iWUE and growth in the beech forests growing in the more standard‐adequate environments of higher altitudes in the last 26 years, the rate of sequestration of C into temperate ecosystems may not increase with increasing atmospheric CO₂ concentrations as predicted by most models based on short‐term small scale experiments.     

Remote monitoring of parental incubation conditions in the greater sandhill crane

To monitor incubation conditions in nests of greater sandhill cranes, a radiotrans-mitting egg was built using six temperature sensors, a position sensor, and a light sensor. Sensor readings were received, along with time of observations, and stored in a computer. The egg was used to monitor incubation in nests of six pairs of cranes during 1987 and 1988. Ambient temperature was also measured. Analysis of covariance (ANCOVA) was used to relate highest egg temperature, core egg temperature, and lowest egg temperature to ambient temperature, time since the egg was last turned, and time since the beginning of incubation. Ambient temperature had the greatest effect on egg temperature (P < 0.0001), followed by the time since the beginning of incubation and time since the egg was last turned. Pair effect, the class variable in the ANCOVA, was also very significant (P < 0.0001). A nine-term Fourier series was used to estimate the average core egg temperature versus time of day and was found to fit the data well (r² = 0.94). The Fourier series will be used to run a mechanical incubator to simulate natural incubation conditions for cranes. © 1995 Wiley-Liss, Inc.     

Active‐Site Imprinting: Preparation of Fe–N–C Catalysts from Zinc Ion–Templated Ionothermal Nitrogen‐Doped Carbons

Atomically dispersed Fe–N–C catalysts are considered the most promising precious‐metal‐free alternative to state‐of‐the‐art Pt‐based oxygen reduction electrocatalysts for proton‐exchange membrane fuel cells. The exceptional progress in the field of research in the last ≈30 years is currently limited by the moderate active site density that can be obtained. Behind this stands the dilemma of metastability of the desired FeN₄ sites at the high temperatures that are believed to be a requirement for their formation. It is herein shown that Zn²⁺ ions can be utilized in the novel concept of active‐site imprinting based on a pyrolytic template ion reaction throughout the formation of nitrogen‐doped carbons. As obtained atomically dispersed Zn–N–Cs comprising ZnN₄ sites as well as metal‐free N₄ sites can be utilized for the coordination of Fe²⁺ and Fe³⁺ ions to form atomically dispersed Fe–N–C with Fe loadings as high as 3.12 wt%. The Fe–N–Cs are active electocatalysts for the oxygen reduction reaction in acidic media with an onset potential of E₀ = 0.85 V versus RHE in 0.1 m HClO₄. Identical location atomic resolution transmission electron microscopy imaging, as well as in situ electrochemical flow cell coupled to inductively coupled plasma mass spectrometry measurements, is employed to directly prove the concept of the active‐site imprinting approach.     

High-resolution sea surface temperature and salinity dynamics in the northern Okinawa Trough over the last 24 kyr

Based on the high-resolution Mg/Ca and oxygen isotope ratio (δ¹⁸O) of planktonic foraminifera Globigerinoides ruber, sea surface temperature (SST) and salinity (SSS) were reconstructed in Core PC-1 from the northern Okinawa Trough during the last 24 kyr. From the last glacial maximum to Holocene, SST varied from 20.2°C to 24.6°C. Millennial-scale climatic events of the SST during the last glacial, such as the Heinrich events, Bølling-Allerød warming, and Younger Dryas, have been identified, which are synchronous with the climate changes in the North Atlantic, suggesting a teleconnection between the northwestern Pacific and the North Atlantic. During the last 24 kyr, the SSS variation can be divided into three parts: (1) during 21–15.5 ka, there was a significantly low SSS; (2) during 15.5–11.7 ka, the SSS increased obviously; (3) since 11.7 ka, the SSS is relatively stable. In order to discuss the main factors influencing the SSS in the northern Okinawa Trough, the relative abundance of Pulleniatina obliquiloculata and the oxygen isotope difference between the northern and middle Okinawa Trough (Δδ¹⁸O_sw) have been used to indicate the intensity of the Kuroshio Current and Changjiang freshwater discharge, respectively. The Δδ¹⁸O_sw result shows that there is a large amount of Changjiang freshwater emptied into the northern Okinawa Trough during 18–15.5 ka, which is caused by the subtropical monsoon rain band lingering in the lower reaches of the Changjiang River drainage, supporting the Jet Transition Hypothesis. As the Kuroshio Current strengthened since 15.5 ka as indicated by the increased relative abundance of P. obliquiloculata, the variation of Kuroshio Current became the more important contribution to the SSS in the study region. The results of our study indicate that the key factor influencing the SSS in the northern Okinawa Trough is variable during the last 24 kyr.     

Variability of Coastal and Ocean Water Temperature in the Upper 700 m along the Western Iberian Peninsula from 1975 to 2006

Temperature is observed to have different trends at coastal and ocean locations along the western Iberian Peninsula from 1975 to 2006, which corresponds to the last warming period in the area under study. The analysis was carried out by means of the Simple Ocean Data Assimilation (SODA). Reanalysis data are available at monthly scale with a horizontal resolution of 0.5°×0.5° and a vertical resolution of 40 levels, which allows obtaining information beneath the sea surface. Only the first 21 vertical levels (from 5.0 m to 729.35 m) were considered here, since the most important changes in heat content observed for the world ocean during the last decades, correspond to the upper 700 m. Warming was observed to be considerably higher at ocean locations than at coastal ones. Ocean warming ranged from values on the order of 0.3°C dec⁻¹ near surface to less than 0.1°C dec⁻¹ at 500 m, while coastal warming showed values close to 0.2°C dec⁻¹ near surface, decreasing rapidly below 0.1°C dec⁻¹ for depths on the order of 50 m. The heat content anomaly for the upper 700 m, showed a sharp increase from coast (0.46 Wm⁻²) to ocean (1.59 Wm⁻²). The difference between coastal and ocean values was related to the presence of coastal upwelling, which partially inhibits the warming from surface of near shore water.     

Sampling grain influences trends in vegetation composition and diversity with time since fire in Australian heathland

Scale‐dependency of pattern and process is well‐understood for many ecological communities; however, the influence of spatial scale (sampling grain) in detecting temporal change in communities is less well‐understood. The temperate lowland heathlands of south‐east Australia are one of the most fire‐prone ecosystems on earth. Despite the extensive literature documenting the effect of time since fire on heathlands, we know little about how sampling grain influences trends in vegetation variables over time, and whether these trends are scale‐dependent. Using 3500 ha of heathland in the Gippsland Lakes Coastal Park, south‐east Australia, we investigated how above‐ground species composition and diversity, and trends in these variables with increasing time since fire, were influenced by sampling grain (1 m², 10 m², 100 m², 900 m², 1 ha, 4 ha). Sampling grain influenced patterns detected in vegetation variables and in some instances, significantly affected their relationship with time since fire. Richness decreased with time since fire, with mean richness decreasing at three of the four grains, while total richness decreased at half of the sampled grains. Evenness (J) decreased with increasing time since fire for all grains except 1 m². The decline in diversity (H) with time since fire appeared to be independent of scale, as all grains decreased significantly with increasing time since fire. Community heterogeneity demonstrated a weak response to time since fire across most grains. Changes in composition among young (0–6 years since fire), intermediate (9–19 years) and old (23–27 years) sites were dependent on sampling grain, with all grains exhibiting significant differences in composition, apart from the 1 m² grain and the 100 m² grain (presence/absence data). Overall, species composition, richness, evenness, diversity and community heterogeneity were dependent on the scale at which the vegetation was sampled. In addition, trends in many of these vegetation variables with increasing time since fire were scale‐dependent. This work provides strong evidence that sampling at multiple grains contributes substantially to understanding pattern and process in heathlands.     

The influence of dominant shrubs,fire, and time since fire on soil seed banks in mixed chaparral

The composition and density of soil seed banks beneath co-occurring Adenostoma fasciculatum and Ceanothus greggii shrubs from three chaparral stands last burned 9, 35 and 85 years before 1986 were investigated. The overall density of seeds in the soil, as estimated by germinations under greenhouse conditions, increased with time since fire (ca. 8000 to 25000/m²). However, this increase was due entirely to the accumulation of A. fasciculatum seed in the soil (ca. 2000 to 21000/m²). In contrast, the density of C. greggii seed was different in each of the three stands, but was not correlated with time since fire: maximum densities were recorded from the 35 year old stand (ca. 2000/m²).A total of 31 taxa germinated and 17 occurred in sufficient numbers to be analyzed statistically. Germinable seed densities of three herb species were not influenced by soil source (beneath A. fasciculatum or C. greggii), time since fire, or the direct effects of a controlled fire treatment. Germinable seed densities of a further nine species were significantly influenced by the elapsed time since stands last burned. The densities of four decreased and five increased. Four of the species that increased in seed density over the three stands were annuals, suggesting that the chaparral sub-canopy habitat is not as unfavorable for annuals as is often assumed. The fire treatment decreased germinable seed densities of four annual species by 40–70%, but increased the germinable seed densities of the shrubs A. fasciculatum and C. greggii, and the annual Phacelia brachyloba. Our results indicate that seeds of A. fasciculatum will increase in the soil bank for at least 85 years after fire in chaparral where it is dominant. In contrast, seed reserves of C. greggii appear to be influenced primarily by site-specific patterns of seed production and by the intensity of post-dispersal seed predation.     

Effectiveness of pertussis vaccination and duration of immunity

Background:A resurgence of pertussis cases among both vaccinated and unvaccinated people raises questions about vaccine effectiveness over time. Our objective was to study the effectiveness of the pertussis vaccine and characterize the effect of waning immunity and whole-cell vaccine priming.Methods:We used the test-negative design, a nested case–control study with test-negative individuals as controls. We constructed multivariable logistic regression models to estimate odds ratios (ORs). Vaccine effectiveness was calculated as (1 – OR) × 100. We assessed waning immunity by calculating the odds of developing pertussis per year since last vaccination and evaluated the relative effectiveness of priming with acellular versus whole-cell vaccine.Results:Between Dec. 7, 2009, and Mar. 31, 2013, data on 5867 individuals (486 test-positive cases and 5381 test-negative controls) were available for analysis. Adjusted vaccine effectiveness was 80% (95% confidence interval [CI] 71% to 86%) at 15–364 days, 84% (95% CI 77% to 89%) at 1–3 years, 62% (95% CI 42% to 75%) at 4–7 years and 41% (95% CI 0% to 66%) at 8 or more years since last vaccination. We observed waning immunity with the acellular vaccine, with an adjusted OR for pertussis infection of 1.27 (95% CI 1.20 to 1.34) per year since last vaccination. Acellular, versus whole-cell, vaccine priming was associated with an increased odds of pertussis (adjusted OR 2.15, 95% CI 1.30 to 3.57).Interpretation:We observed high early effectiveness of the pertussis vaccine that rapidly declined as time since last vaccination surpassed 4 years, particularly with acellular vaccine priming. Considering whole-cell vaccine priming and/or boosters in pregnancy to optimize pertussis control may be prudent.Whooping cough, or pertussis, is a highly contagious respiratory infection that has been inadequately controlled compared with other vaccine-preventable diseases. The incidence of pertussis in Canada decreased from 156 cases per 100 000 population during the prevaccination era to a historic low of 2.0 per 100 000 in 2011, increased to 13.9 in 2012, and then decreased to 3.6 in 2013.¹Ontario, Canada’s most populous province with a population of 13.5 million in 2013, experienced a localized outbreak in 2012. This outbreak started in a largely unvaccinated religious community and disproportionately affected infants, but then spread to the general population and mostly involved adolescents.² Consequently, the outbreak raised questions about product-specific vaccine effectiveness and waning immunity.Pertussis vaccines have been available in Ontario for more than 70 years. In 1997, owing to concerns about safety and effectiveness, acellular pertussis vaccine replaced the whole-cell product that had been in use since 1984.^3–5 In Ontario, only the 5-component acellular vaccine (containing pertussis toxoid, filamentous hemagglutinin, pertactin, and fimbriae types 2 and 3) has been available for infants and toddlers. Vaccination against pertussis is recommended at 2, 4, 6 and 18 months, and at 4–6 years. In 2003, an adolescent dose at 14–16 years was introduced, and in 2011, a program was started for single-dose adult vaccination against pertussis.⁶Other jurisdictions in Canada, the United States and Australia have reported lower effectiveness with the acellular product and rapidly waning immunity.^7–11 Canada has a unique history of using a whole-cell vaccine with lower effectiveness, and also has different secular trends in pertussis incidence and vaccination coverage, necessitating local evaluation of the effectiveness of the pertussis vaccine to inform vaccination policy. Our objective was to study the effectiveness of the pertussis vaccine in Ontario while characterizing the effect of waning immunity and whole-cell vaccine priming.