Human Population Change Research Articles

Human population reduction is not a quick fix for environmental problems.

The inexorable demographic momentum of the global human population is rapidly eroding Earth's life-support system. There are consequently more frequent calls to address environmental problems by advocating further reductions in human fertility. To examine how quickly this could lead to a smaller human population, we used scenario-based matrix modeling to project the global population to the year 2100. Assuming a continuation of current trends in mortality reduction, even a rapid transition to a worldwide one-child policy leads to a population similar to today's by 2100. Even a catastrophic mass mortality event of 2 billion deaths over a hypothetical 5-y window in the mid-21(st) century would still yield around 8.5 billion people by 2100. In the absence of catastrophe or large fertility reductions (to fewer than two children per female worldwide), the greatest threats to ecosystems--as measured by regional projections within the 35 global Biodiversity Hotspots--indicate that Africa and South Asia will experience the greatest human pressures on future ecosystems. Humanity's large demographic momentum means that there are no easy policy levers to change the size of the human population substantially over coming decades, short of extreme and rapid reductions in female fertility; it will take centuries, and the long-term target remains unclear. However, some reduction could be achieved by midcentury and lead to hundreds of millions fewer people to feed. More immediate results for sustainability would emerge from policies and technologies that reverse rising consumption of natural resources.

Demographic change, tourism expenditure and life cycle behaviour

The paper explores how demographic changes in human populations may impact on tourism decision-making of households over their life cycle. By means of hurdle models, the study focuses respectively on the decision to travel domestically or abroad and investigates if statistically significant differences exist as to the impact of age and cohort on the decision to travel and tourism expenditure. Using a vast dataset on Italian Household Expenditures over the period 1997–2007 the empirical results show that demographic aspects do have a strong effect on the tourism behaviour of families and that cohort and age effects act differently on the decision of households to make a trip and on how much they spend on tourism. Age has a negative effect on the desire to travel but a positive effect on tourism expenditure. On the other hand, older cohorts are inclined to travel but they have a low propensity to spend on tourism. Relevant differences in income elasticity along the life cycle of households have also been found. Finally, age and cohort aspects have a different effect on the decision as to whether to travel nationally or internationally.

An early assemblage of obsidian artifacts

Paleolithic Tools Levallois technology is the name for the stone knapping technique used to create tools thousands of years ago. The technique appeared in the archeological record across Eurasia 200 to 300 thousand years ago (ka) and appeared earlier in Africa. Adler et al. challenge the hypothesis that the technique's appearance in Eurasia was the result of the expansion of hominins from Africa. Levallois obsidian artifacts in the southern Caucasus, dated at 335 to 325 ka, are the oldest in Eurasia. This suggests that Levallois technology may have evolved independently in different hominin populations. Stone technology cannot thus be used as a reliable indicator of Paleolithic human population change and expansion. Science , this issue p. [1609][1] [1]: /lookup/doi/10.1126/science.1256484

Early Levallois technology and the Lower to Middle Paleolithic transition in the Southern Caucasus.

The Lower to Middle Paleolithic transition (~400,000 to 200,000 years ago) is marked by technical, behavioral, and anatomical changes among hominin populations throughout Africa and Eurasia. The replacement of bifacial stone tools, such as handaxes, by tools made on flakes detached from Levallois cores documents the most important conceptual shift in stone tool production strategies since the advent of bifacial technology more than one million years earlier and has been argued to result from the expansion of archaic Homo sapiens out of Africa. Our data from Nor Geghi 1, Armenia, record the earliest synchronic use of bifacial and Levallois technology outside Africa and are consistent with the hypothesis that this transition occurred independently within geographically dispersed, technologically precocious hominin populations with a shared technological ancestry.

Solving the Emerging Infectious Disease Crisis*

Today I speak to you as a witness from ‘‘ground zero’’ of the biodiversity crisis. I bring an urgent message. The human population grows daily, it’s on the move, and it’s carving a deep technological footprint on this planet. We alter landscapes and perturb ecosystems, inserting ourselves and other species into novel regions of the world, leading to potentially irreversible changes in the biosphere. This is not news. Half a century ago, Charles Elton, a founder of modern ecology, wrote, ‘‘We must make no mistake; we are seeing one of the greatest historical convulsions in the world’s fauna and flora.’’ We are also in the midst of an epidemiological crisis. Climate change alters movements and geographic distributions for myriad species. Transportation of people and goods carries countless pathogens around the globe. This brings isolated species into sudden contact. Pathogens encounter hosts with no resistance and no time to evolve any. This is also not news: Maladies rare or unknown 2 or 3 decades ago, like HIV (human immunodeficiency virus) and Ebola, West Nile virus and avian influenza, have become commonplace. In such a world—this world—events like these are ongoing. Scarcely a week passes without news of some freshly discovered strain of pathogen trading up to a human host...or bald eagles...or crop plants...or sea anemones. This is the crisis of emerging infectious disease (EID). We think of EID as isolated events, and we react only after the fact. We allocate massive resources to pathogens that have already made themselves known, while ignoring the far greater threat posed by those waiting in the wings. The ones we know are just the tip of the iceberg:—80–90% percent of the world’s pathogens haven’t been discovered yet. They’re discovering us easily enough—weekly outbreaks and endlessly mutating strains of recent years are ample evidence of that. This succession of crises is the new status quo. They’re far better at finding us than we have been at finding them. Why? The current EID crisis is a new manifestation of an old and repeating phenomenon. The rules have not changed. Every episode of global climate change and ecological perturbation throughout Earth history has produced new pathogens. More than a million years ago, our African ancestors moved from forest to savannah. Adopting a predatory lifestyle, sharing prey with grassland carnivores, early humans acquired pathogens previously found in hyenas, large cats, and African hunting dogs. They carried those pathogens out of Africa, where they added native hosts in new environments, while native pathogens returned the favor, infecting the newly arrived humans. Agriculture and urbanization brought people and animals into even closer contact, making infection and transmission easier than ever. In the past 100,000 yr, agriculture, domestication, and urbanization have disseminated EID risk on a global scale. If doctors had existed in those times, they would have remarked on a worrisome surge in the number of EIDs, responding to the crisis as best they could, after the fact. In the past 50 yr, exploding human population, rapid transit, and climate change have produced the real-time crisis you see on television daily. The EID crisis is a medical issue in only a superficial sense. It’s more fundamentally an evolutionary and ecological issue, a predictable consequence of separated species brought into close contact. The difference today is that human activity accelerates the rate of introductions, so outbreaks occur more frequently and over a wider geographic range than ever before. The potential for EID is a ‘‘built-in feature’’ of evolution. Research shows that those species best at surviving climate change will be the primary sources of EID. Pathogens are not only good at finding us, they are really good at surviving. There are many, not a few, evolutionary ‘‘accidents waiting to happen’’ out there, requiring only the catalyst of climate change, species introductions, and the intrusion of humans into areas they have never inhabited before. All of these are happening right now. * Speech given in acceptance of the Helminthological Society of Washington’s 2012 Anniversary Award. Comp. Parasitol. 81(2), 2014, pp. 152–154

Prehistoric demographic fluctuations in China inferred from radiocarbon data and their linkage with climate change over the past 50,000 years

Historic human–climate interactions have been of interest to scholars for a long time. However, exploring the long-term relation between prehistoric demography and climate change remains challenging because of the absence of an effective proxy for population reconstruction. Recently, the summed probability distribution of archaeological radiocarbon dates has been widely used as a proxy for human population levels, although researchers recognize that such usage must be cautious. This approach is rarely applied in China due to the lack of a comprehensive archaeological radiocarbon database, and thus the relation between human population and climate change in China remains ambiguous. Herein we systematically compile an archaeological 14C database (n = 4656) for China for the first time. Using the summed probability distributions of the radiocarbon dates alongside high-resolution palaeoclimatic records, we show that: 1) the commencement of major population expansion in China was at 9 ka cal BP, occurring after the appearance of agriculture and associated with the early Holocene climate amelioration; 2) the major periods of small population size and population decline, i.e., 46–43 ka cal BP, 41–38 ka cal BP, 31–28.6 ka cal BP, 25–23.5 ka cal BP, 18–15.2 ka cal BP, and 13–11.4 ka cal BP, correspond well with the dating of abrupt cold events in the Last Glacial (LG) such as the Heinrich and Younger Dryas (YD) events, while the major periods of high-level population in the Holocene, i.e., 8.5–7 ka cal BP, 6.5–5 ka cal BP and 4.3–2.8 ka cal BP, occur at the same times as warm-moist conditions and Neolithic cultural prosperity, suggesting that abrupt cooling in the climate profoundly limited population size and that mild climate episodes spurred a growth in prehistoric populations and advances in human cultures; and 3) populations in different regions experience different growth trajectories and that their responses to climate change are varied, due to both regional environmental diversity and the attainment of different levels of adaptive strategies.

Functional evaluation of hTM, CD46 and HLA‐E transgenes in vitro and in pig leg xenoperfusion experiments

BackgroundBesides α1,3 galactosyltransferase (Gal) gene knockout several transgene combinations to prevent pig‐to‐human xenograft rejection are being investigated. hCD46/HLA‐E double transgenic pigs were tested for prevention of xenograft rejection in an ex vivo pig‐to‐human xenoperfusion model. In addition, expression of human thrombomodulin (hTM‐) on wild‐type and/or multi‐transgenic (GalTKO/hCD46) background was evaluated to overcome pig‐to‐human coagulation incompatibility.MethodshCD46/HLA‐E double transgenic as well as wild‐type pig forelimbs were ex vivo perfused with whole, heparinized human blood and autologous blood, respectively. Blood samples were analyzed for production of porcine and/or human inflammatory cytokines. Biopsy samples were examined for deposition of complement proteins as well as E‐selectin and VCAM‐1 expression. Serial blood cell counts were performed to analyze changes in human blood cell populations. In vitro, PAEC were analyzed for ASGR1 mediated human platelet phagocytosis. In addition, a biochemical assay was performed using hTM‐only and multi‐transgenic (GalTKO/hCD46/hTM) pig aortic endothelial cells (PAEC) to evaluate the ability of hTM to generate activated protein C (APC). Subsequently, the anti‐coagulant properties of hTM were tested in a microcarrier based coagulation assay with PAEC and human whole blood.ResultsNo hyperacute rejection was seen in the ex vivo perfusion model. Extremity perfusions lasted for up to 12 h without increase of vascular resistance and had to be terminated due to continuous small blood losses. Plasma levels of porcine IL1β (P < 0.0001), and IL‐8 (P = 0.019) as well as human C3a, C5a and soluble C5b‐9 were significantly (P < 0.05–<0.0001) lower in blood perfused through hCD46/HLA‐E transgenic as compared to wild‐type limbs. C3b/c, C4b/c, and C6 deposition as well as E‐selectin and VCAM‐1 expression were significantly (P < 0.0001) higher in tissue of wild‐type as compared to transgenic limbs. Preliminary immunofluorescence staining results showed that the expression of hCD46/HLA‐E is associated with a reduction of NK cell tissue infiltration (P < 0.05). A rapid decrease of platelets was observed in all xenoperfusions. In vitro findings showed that PAEC express ASGR1 and suggest that this molecule is involved in human platelet phagocytosis. In vitro, we found that the amount of APC in the supernatant of hTM transgenic cells increased significantly (P < 0.0001) with protein C concentration in a dose‐dependent manner as compared to control PAEC lacking hTM, where the turnover of the protein C remained at the basal level for all of the examined concentration. In further experiments, hTM also showed the ability to prevent blood coagulation by three‐ to four‐fold increased (P < 0.001) clotting time as compared to wild‐type PAEC. The formation of TAT complexes was significantly lower when hTM‐transgenic cells (P < 0.0001) were used as compared to wild‐type cells.ConclusionsTransgenic hCD46/HLA‐E expression clearly reduced humoral xenoresponses since the terminal pathway of complement, endothelial cell activation, inflammatory cytokine production and NK‐cell tissue infiltration were all down‐regulated. We also found ASGR1 expression on the vascular endothelium of pigs, and this molecule may thus be involved in binding and phagocytosis of human platelets during pig‐to‐human xenotransplantation. In addition, use of the hTM transgene has the potential to overcome coagulation incompatibilities in pig‐to‐human xenotransplantation.

Changes in Human Population Characteristics and Environmental Change in the West Matogoro Catchment Area of Songea, Tanzania

The study was carried out in West Matogoro Catchment Area (WMCA) of Songea, Tanzania, to establish whether for the period between intercensal periods 1978-1988 and 1988-2002, and between 2002 and 2005 characteristics of human population of the area had changed in terms of size, age structure and sex composition. In case it did, then the study had to establish whether such changes may be used to explain the observed forest cover change that occurred in the area. Establishing whether the observed changes were proportionate was important in linking the relationship among factors at hand. The study partly tested the thesis by Liu and others which linked human population changes and their implications to the panda habitat [1]. The findings indicated existence of changes in human population characteristics for the period under review. Variations in terms of population size, age structure and sex composition were realized. While growth was measured by the total population and size of age group of the environmentally active population as identified by the study by Haule, sex composition was determined by sex ratios [2]. The environmentally active age group included males aged 20 to 44 and females aged 10 to 44, i.e. the key actors in felling trees for farm expansion and for firewood respectively. Geographic Information System (GIS) evidence indicated progressive forest cover deterioration. When compared, the changes in human population characteristics and those of the forest cover were noted to be un-proportional. Variations were in terms of increase in human population size and expansion of age group of the “actors” thus attributed to the augmenting deforestation. A positive relationship was demonstrated between population growth, expansion of age segment of the key actors and expanded deforestation. We reiterate that any sustainable measures to address the environmental issues should take into account changes in demographic characteristics of the in Situ population which forms the locus of the interface between population and environment. These factors signify the intensity and duration of the involved forces that characterize forest cover quality.

Extinction in Eden: identifying the role of climate change in the decline of the koala in south-eastern NSW

Context Reviews of climate change in Australia have identified that it is imposing additional stresses on biodiversity, which is already under threat from multiple human impacts. Aims The present study aimed to determine the contributions of several factors to the demise of the koala in the Eden region in south-eastern New South Wales and, in particular, to establish to what extent climate change may have exacerbated the decline. Methods The study built on several community-based koala surveys in the Eden region since 1986, verified through interviews with survey respondents. Historical records as far back as the late 19th century, wildlife databases and field-based surveys were used to independently validate the community survey data and form a reliable picture of changes in the Eden koala population. Analysis of the community survey data used a logistic model to assess the contribution of known threats to koalas, including habitat loss measured as changes in foliage projective cover, fire, increases in the human population and climate change in the form of changes in temperature and rainfall, to the regional decline of this species. Key results We found a marked, long-term shrinkage in the distribution of the koala across the Eden region. Our modelling demonstrated that a succession of multiple threats to koalas from land use (human population growth and habitat loss) and environmental change (temperature increase and drought) were significant contributors to this decline. Conclusions Climate change, particularly drought and rising temperatures, has been a hitherto hidden factor that has been a major driver of the decline of the koala in the Eden region. Implications Development of strategies to help fauna adapt to the changing climate is of paramount importance, particularly at a local scale.

The Younger Dryas impact hypothesis: a critical review

The Younger Dryas impact hypothesis suggests that multiple extraterrestrial airbursts or impacts resulted in the Younger Dryas cooling, extensive wildfires, megafaunal extinctions and changes in human population. After the hypothesis was first published in 2007, it gained much criticism, as the evidence presented was either not indicative of an extraterrestrial impact or not reproducible by other groups. Only three years after the hypothesis had been presented, a requiem paper was published. Despite this, the controversy continues. New evidence, both in favour and against the hypothesis, continues to be published.In this review we briefly summarize the earlier debate and critically analyse the most recent reported evidence, including magnetic microspherules, nanodiamonds, and iridium, shocked quartz, scoria-like objects and lechatelierite. The subsequent events proposed to be triggered by the impact event, as well as the nature of the event itself, are also briefly discussed. In addition we address the timing of the Younger Dryas impact, a topic which, despite its importance, has not gained much attention thus far. We show that there are three challenges related to the timing of the event: accurate age control for some of the sites that are reported to provide evidence for the impact, linking these sites to the onset of the Younger Dryas and, most importantly, an apparent age discrepancy of up to two centuries between different sites associated with the proposed impact event. We would like to stress that if the markers at different locations have been deposited at different points in time, they cannot be related to the same event. Although convincing evidence for the hypothesis that multiple synchronous impacts resulted in massive environmental changes at ∼12,900 yrs ago remains debatable, we conclude that some evidence used to support the Younger Dryas impact hypothesis cannot fully be explained at this point in time.

Status of exotic grasses and grass-like vegetation and potential impacts on wildlife in New England

The Northeastern section of the United States, known as New England, has seen vast changes in land cover and human population over the past 3 centuries. Much of the region is forested; grasslands and other open-land cover types are less common, but provide habitat for many species that are currently declining in abundance and distribution. New England also consists of some of the most densely populated and developed states in the country. The origin, distribution, and spread of exotic species are highly correlated with human development. As such, exotics are common throughout much of New England, including several species of graminoids (grasses and grass-like plants such as sedges and rushes). Several of the more invasive grass species can form expansive dense mats that exclude native plants, alter ecosystem structure and functions, and are perceived to provide little-to-no value as wildlife food or cover. Although little research has been conducted on direct impacts of exotic graminoids on wildlife populations in New England, several studies on the common reed (Phragmites australis) in salt marshes have shown this species to have variable effects as cover for birds and other wildlife, depending on the distribution of the plant (e.g., patches and borders of reeds are used more by wildlife than expansive densely growing stands). Direct impacts of other grasses on wildlife populations are largely unknown. However, many of the invasive graminoid species that are present in New England have the capability of outcompeting native plants and thereby potentially affecting associated fauna. Preservation, protection, and restoration of grassland and open-land cover types are complex but necessary challenges in the region to maintain biological and genetic diversity of grassland, wetland, and other open-land obligate species. © 2013 The Wildlife Society.

Design of an agent-based model to examine population–environment interactions in Nang Rong District, Thailand

The design of an agent-based model (ABM) is described that integrates Social and Land Use Modules to examine population–environment interactions in a former agricultural frontier in Northeastern Thailand. The ABM is used to assess household income and wealth derived from agricultural production of lowland, rain-fed paddy rice and upland field crops in Nang Rong District as well as remittances returned to the household from family migrants who are engaged in off-farm employment in urban destinations. The ABM is supported by a longitudinal social survey of nearly 10,000 households, a deep satellite image time-series of land use change trajectories, multi-thematic social and ecological data organized within a GIS, and a suite of software modules that integrate data derived from an agricultural cropping system model (DSSAT – Decision Support for Agrotechnology Transfer) and a land suitability model (MAXENT – Maximum Entropy), in addition to multi-dimensional demographic survey data of individuals and households.The primary modules of the ABM are the Initialization Module, Migration Module, Assets Module, Land Suitability Module, Crop Yield Module, Fertilizer Module, and the Land Use Change Decision Module. The architecture of the ABM is described relative to module function and connectivity through uni-directional or bi-directional links. In general, the Social Modules simulate changes in human population and social networks, as well as changes in population migration and household assets, whereas the Land Use Modules simulate changes in land use types, land suitability, and crop yields. We emphasize the description of the Land Use Modules – the algorithms and interactions between the modules are described relative to the project goals of assessing household income and wealth relative to shifts in land use patterns, household demographics, population migration, social networks, and agricultural activities that collectively occur within a marginalized environment that is subjected to a suite of endogenous and exogenous dynamics.

Long-Term Changes in Human Colonic Bifidobacterium Populations Induced by a 5-Day Oral Amoxicillin-Clavulanic Acid Treatment

The objective of this study was to assess the possible modifications due to amoxicillin-clavulanic acid (AMC) treatment on total bacteria and on Bifidobacterium species balance in human colonic microbiota. Eighteen healthy volunteers (19 to 36 years old) were given a 875/125 mg dose of AMC twice a day for 5 days. Fecal samples were obtained before and after antibiotic exposure. After total DNA extraction, total bacteria and bifidobacteria were specifically quantified using real-time PCR. Dominant species were monitored over time using bacterial and bifidobacterial Temporal Temperature Gradient gel Electrophoresis (TTGE). At the end of AMC exposure, total bacterial concentrations as well as bifidobacteria concentrations were significantly reduced compared to before AMC exposure:10.7±0.1 log10 16S rRNA gene copies/g vs 11.1±0.1 log10 (p = 0.003) and 8.1±0.5 log10 16S rRNA gene copies/g vs 9.4±0.3 log10 (p = 0.003), respectively. At the same time, the mean similarity percentages of TTGE bacteria and TTGE bifidobacteria profiles were significantly reduced compared to before AMC exposure: 51.6%±3.5% vs 81.4%±2.1% and 55.8%±7.6% vs 84.5%±4.1%, respectively. Occurrence of B. adolescentis, B. bifidum and B. pseudocatenulatum/B. catenulatum species significantly decreased. Occurrence of B. longum remained stable. Moreover, the number of distinct Bifidobacterium species per sample significantly decreased (1.5±0.3 vs 2.3±0.3; p = 0.01). Two months after AMC exposure, the mean similarity percentage of TTGE profiles was 55.6% for bacteria and 62.3% for bifidobacteria. These results clearly demonstrated that a common antibiotic treatment may qualitatively alter the colonic microbiota. Such modifications may have potential long-term physiological consequences.

Natural and anthropogenic variations in methane sources during the past two millennia

Methane is an important greenhouse gas that is emitted from multiple natural and anthropogenic sources. Atmospheric methane concentrations have varied on a number of timescales in the past, but what has caused these variations is not always well understood. The different sources and sinks of methane have specific isotopic signatures, and the isotopic composition of methane can therefore help to identify the environmental drivers of variations in atmospheric methane concentrations. Here we present high-resolution carbon isotope data (δ(13)C content) for methane from two ice cores from Greenland for the past two millennia. We find that the δ(13)C content underwent pronounced centennial-scale variations between 100 BC and AD 1600. With the help of two-box model calculations, we show that the centennial-scale variations in isotope ratios can be attributed to changes in pyrogenic and biogenic sources. We find correlations between these source changes and both natural climate variability--such as the Medieval Climate Anomaly and the Little Ice Age--and changes in human population and land use, such as the decline of the Roman empire and the Han dynasty, and the population expansion during the medieval period.

Anticipated human population and climate change effects on algal blooms of a toxic haptophyte in the south-central USA1This article is derived from a special session entitled “A New Hydrology: Inflow Effects on Ecosystem Form and Functioning” that took place at the February 2011 ASLO Aquatic Sciences conference in San Juan, Puerto Rico.

Effects of inflow on phytoplankton dynamics and assemblage structure have long been an interest of ecologists and resource managers, especially when they are linked to the incidence of harmful algal blooms. The frequency and magnitude of Prymnesium parvum bloom-preventing inflows likely in a drier landscape of south-central USA was explored, along with the relative importance of various factors important to blooms. We show that the number of large inflow events necessary to prevent blooms might decrease between 25% and 65% under drier conditions likely for this region. Long duration inflow events that are critical to lake flushing could nearly disappear, with inflow events lasting longer than 20 days decreasing 40-fold. These findings suggest that the frequency of P. parvum blooms and fish-kill events might increase in this region with human population and climate change. Multivariate analyses of monitoring data from multiple lakes indicate that other factors may be equally important to bloom occurrences. Inverse trends between toxic bloom events and nutrient concentrations, cyanobacteria, and lower pH are apparent. During periods when P. parvum populations were not toxic, an inverse relationship with zooplankton was observed. These other factors might be harnessed to mitigate P. parvum blooms in the future when inflows are reduced.

The Limits to Sustainability Science: Ecological Constraints or Endless Innovation?

The Limits to Sustainability Science: Ecological Constraints or Endless Innovation?

Distribution patterns of invasive alien species in Alabama, USA

Invasive alien species (IAS) cause environmental and economical problems. How to effectively manage all IAS at a large area is a challenge. Hypotheses about IAS (such as the “human activity” hypothesis, the “biotic acceptance” and the “biotic resistance”) have been proposed from numerous studies. Here the state of Alabama in USA, widely occupied by IAS, is used as a case study for characterizing the emergent patterns of IAS. The results indicate that most IAS are located in metropolitan areas and in the Black Belt area which is a historical intensive land use area. There are positive relationships between the richness of IAS and the change of human population, the species richness and the number of endangered species, as well as the total road length and farmland area across Alabama. This study partially supports the above three hypotheses and provides a general pattern of local IAS. Based on possible processes related with IAS, some implications for strategically managing local IAS are discussed.

Instantaneous Mass Profiling of Live Cells via Live Cell Interferometry

Live Cell Interferometry (LCI) is a real time imaging technology that is extremely well suited to capture motion on the micro- and even nano-scale, with a temporal dynamic range and field of view that far exceeds scanning probe techniques. We will describe the development and application of LCI for rapid, real-time quantification of single-cell mass changes in human embryonic stem cells and populations of cells exposed to a changing external and internal environments. LCI is a conceptual advance in providing a mechanism to assess whole populations of cells, one cell at a time, for identifying, tracking/monitoring, and measuring cellular responses, such as to therapeutic drugs.View Large Image | View Hi-Res Image | Download PowerPoint Slide

Effect of glycation of bovine β-lactoglobulin with galactooligosaccharides on the growth of human faecal bacteria

The in vitro fermentation selectivity of purified galactooligosaccharides (GOS) after their conjugation with bovine β-lactoglobulin (β-LG) via the Maillard reaction and a subsequent simulated gastrointestinal digestion was evaluated. Changes in human faecal bacterial populations, lactic acid and short-chain fatty acids after 10 h and 24 h of fermentation of the digested β-LG:GOS conjugates revealed that this mixture of glycated peptides had a similar bifidogenic activity to the unconjugated GOS. These findings could open up new applications for Maillard reaction products in the functional foods field.

Generic Modelling of Faecal Indicator Organism Concentrations in the UK

To meet European Water Framework Directive requirements, data are needed on faecal indicator organism (FIO) concentrations in rivers to enable the more heavily polluted to be targeted for remedial action. Due to the paucity of FIO data for the UK, especially under high-flow hydrograph event conditions, there is an urgent need by the policy community for generic models that can accurately predict FIO concentrations, thus informing integrated catchment management programmes. This paper reports the development of regression models to predict base- and high-flow faecal coliform (FC) and enterococci (EN) concentrations for 153 monitoring points across 14 UK catchments, using land cover, population (human and livestock density) and other variables that may affect FIO source strength, transport and die-off. Statistically significant models were developed for both FC and EN, with greater explained variance achieved in the high-flow models. Both land cover and, in particular, population variables are significant predictors of FIO concentrations, with r2 maxima for EN of 0.571 and 0.624, respectively. It is argued that the resulting models can be applied, with confidence, to other UK catchments, both to predict FIO concentrations in unmonitored watercourses and evaluate the likely impact of different land use/stocking level and human population change scenarios.