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Seroprevalence estimation using cross-sectional serosurveys can be challenging due to inadequate or unknown biological cut-off limits of detection. In recent years, diagnostic assay cut-offs, fixed assay cut-offs and more flexible approaches as mixture modelling have been proposed to classify biological quantitative measurements into a positive or negative status. Our objective was to estimate the prevalence of anti-HCV antibodies among drug users (DU) in France in 2011 using a biological test performed on dried blood spots (DBS) collected during a cross-sectional serosurvey. However, in 2011, we did not have a cut-off value for DBS. We could not use the values for serum or plasma, knowing that the DBS value was not necessarily the same. Accordingly, we used a method which consisted of applying a two-component mixture model with age-dependent mixing proportions using penalised splines. The component densities were assumed to be log-normally distributed and were estimated in a Bayesian framework. Anti-HCV prevalence among DU was estimated at 43.3% in France and increased with age. Our method allowed us to provide estimates of age-dependent prevalence using DBS without having a specified biological cut-off value.
Particular attention has been recently devoted to the development of biohybrid photoconverters based on the bacterial Reaction Center (RC) of Rhodobacter sphaeroides. This highly efficient photoenzyme has a conversion yield close to unit that makes it extremely appealing in the field of artificial photosynthesis. Isolated RCs suffer of a limited absorption cross-section in the visible spectral region that limits their applicative employment. Here we report the synthesis of two heptamethine cyanine molecules, whose photophysical properties make them potentially suitable as light harvesting antennas for the RC.
Important Bird and Biodiversity Areas (IBAs) are sites identified as being globally important for the conservation of bird populations on the basis of an internationally agreed set of criteria. We present the first review of the development and spread of the IBA concept since it was launched by BirdLife International (then ICBP) in 1979 and examine some of the characteristics of the resulting inventory. Over 13,000 global and regional IBAs have so far been identified and documented in terrestrial, freshwater and marine ecosystems in almost all of the world’s countries and territories, making this the largest global network of sites of significance for biodiversity. IBAs have been identified using standardised, data-driven criteria that have been developed and applied at global and regional levels. These criteria capture multiple dimensions of a site’s significance for avian biodiversity and relate to populations of globally threatened species (68.6% of the 10,746 IBAs that meet global criteria), restricted-range species (25.4%), biome-restricted species (27.5%) and congregatory species (50.3%); many global IBAs (52.7%) trigger two or more of these criteria. IBAs range in size from < 1 km2 to over 300,000 km2 and have an approximately log-normal size distribution (median = 125.0 km2, mean = 1,202.6 km2). They cover approximately 6.7% of the terrestrial, 1.6% of the marine and 3.1% of the total surface area of the Earth. The launch in 2016 of the KBA Global Standard, which aims to identify, document and conserve sites that contribute to the global persistence of wider biodiversity, and whose criteria for site identification build on those developed for IBAs, is a logical evolution of the IBA concept. The role of IBAs in conservation planning, policy and practice is reviewed elsewhere. Future technical priorities for the IBA initiative include completion of the global inventory, particularly in the marine environment, keeping the dataset up to date, and improving the systematic monitoring of these sites.
Herbicide resistance is ‘wicked’ in nature; therefore, results of the many educational efforts to encourage diversification of weed control practices in the United States have been mixed. It is clear that we do not sufficiently understand the totality of the grassroots obstacles, concerns, challenges, and specific solutions needed for varied crop production systems. Weed management issues and solutions vary with such variables as management styles, regions, cropping systems, and available or affordable technologies. Therefore, to help the weed science community better understand the needs and ideas of those directly dealing with herbicide resistance, seven half-day regional listening sessions were held across the United States between December 2016 and April 2017 with groups of diverse stakeholders on the issues and potential solutions for herbicide resistance management. The major goals of the sessions were to gain an understanding of stakeholders and their goals and concerns related to herbicide resistance management, to become familiar with regional differences, and to identify decision maker needs to address herbicide resistance. The messages shared by listening-session participants could be summarized by six themes: we need new herbicides; there is no need for more regulation; there is a need for more education, especially for others who were not present; diversity is hard; the agricultural economy makes it difficult to make changes; and we are aware of herbicide resistance but are managing it. The authors concluded that more work is needed to bring a community-wide, interdisciplinary approach to understanding the complexity of managing weeds within the context of the whole farm operation and for communicating the need to address herbicide resistance.
Seven half-day regional listening sessions were held between December 2016 and April 2017 with groups of diverse stakeholders on the issues and potential solutions for herbicide-resistance management. The objective of the listening sessions was to connect with stakeholders and hear their challenges and recommendations for addressing herbicide resistance. The coordinating team hired Strategic Conservation Solutions, LLC, to facilitate all the sessions. They and the coordinating team used in-person meetings, teleconferences, and email to communicate and coordinate the activities leading up to each regional listening session. The agenda was the same across all sessions and included small-group discussions followed by reporting to the full group for discussion. The planning process was the same across all the sessions, although the selection of venue, time of day, and stakeholder participants differed to accommodate the differences among regions. The listening-session format required a great deal of work and flexibility on the part of the coordinating team and regional coordinators. Overall, the participant evaluations from the sessions were positive, with participants expressing appreciation that they were asked for their thoughts on the subject of herbicide resistance. This paper details the methods and processes used to conduct these regional listening sessions and provides an assessment of the strengths and limitations of those processes.
Human papillomavirus (HPV) is a DNA virus linked to mucosal and cutaneous carcinogenesis. More than 200 different HPV types exist. We carried out a transversal study to investigate the prevalence of HPV types in two regions of Mexico. A total of 724 genital and non-genital samples from women (F) and men (M) were studied; 241 (33%) from North-Eastern (NE) and 483 (66%) from South-Central (SC) Mexico. The overall prevalence was 87%. In genital lesions from females, the NE group showed a prevalence of HPV types 16 (37%), 6 (13%), 59 (6%), 11, 18 and 66 (5.4% each); and the SC group showed types 6 (17%), 16 (15%), 11 (14.5%), 18 (12%) and 53 (6%). In the genital lesions from males, NE group showed types 16 (38%), 6 (21%), 11 (13%) and 59 plus 31 (7.5%) and the SC group showed types 6 (25%), 11 (22%), 18 (17%) and 16 (11.5%). When the two regions were compared, a higher prevalence of low-risk HPV 6 and 11 was found in the SC region and of high-risk HPV 59, 31 and 66 (the latter can also be present in benign lesions) in the NE region. Our findings complement efforts to understand HPV demographics as a prerequisite to guide and assess the impact of preventive interventions.
Stemming from The Worldwide Donkey Breeds Project, an initiative aiming at connecting international researchers and entities working with the donkey species, molecularly tested pedigree analyses were carried out to study the genetic diversity, structure and historical evolution of the Andalusian donkey breed since the 1980s to infer a model to study the situation of international endangered donkey breeds under the remarkably frequent unknown genetical background status behind them. Demographic and genetic variability parameters were evaluated using ENDOG (v4.8). Pedigree completeness and generation length were quantified for the four gametic pathways. Despite mean inbreeding was low, highly inbred animals were present in the pedigree. Average coancestry, relatedness, and non-random mating degree trends were computed. The effective population size based on individual inbreeding rate was about half when based on individual coancestry rate. Nei’s distances and equivalent subpopulations number indicated differentiated farms in a highly structured population. Although genetic diversity loss since the founder generations could be considered small, intraherd breeding policies and the excessive contribution of few ancestors to the gene pool could lead to narrower pedigree bottlenecks. Long average generation intervals could be considered when reducing inbreeding. Wright’s fixation statistics indicated slight inbreeding between farms. Pedigree shallowness suggested applying new breeding strategies to reliably estimate descriptive parameters and control the negative effects of inbreeding, which could indeed, mean the key to preserve such valuable animal resources avoiding the extinction they potentially head towards, making the present model become an international referent when assessing endangered donkey populations.
Starting from polydisperse diatomaceous earth (DE), we proposed an efficient separation method for obtaining different morphologies of biosilica from diatoms. DE is a very low-cost source of silica containing all the differently nanostructured elements. By a glucose gradient/dialysis, three types of biosilica morphologies were achieved: rods, valves, and clusters. We fully characterized the diatom fractions and we used them to produce fluorescent biosilica platforms (“tabs”). These supports exhibited good resistance in water, ethanol, and soft scraping. A preliminary biologic application by testing Saos-2 proliferation was also performed to check osteoblasts-like cells biologic attitude for this scaffolds with tunable nanostructure.
Introduction: The social determinants of health (SDoH) can play a significant role in a person’s overall wellbeing. This is especially true for adults with mental illness and mental health disorders. In this study, we describe the SDoH of patients presenting to an academic, inner-city emergency department (ED) with an acute mental health complaint (AMHC). Methods: We prospectively identified and enrolled a convenience sample of patients presenting to an ED with an annual census of 85,000 visits. Participants provided informed written consent, and completed a questionnaire package containing questions related to demographics and SDoH. As well, participants were asked to complete four mental health, quality of life, and recovery validated patient-reported outcome measures. Results: A total 108 participants were enrolled in this study, of which 65% were male, aged 37.5 years (IQR 26.7-50.3), 56% Caucasian, and 22% Aboriginal. Depression was the primary diagnosis reported by 55% of participants, with 58.9% meeting the PhQ-9 cutoff for moderate-severe depression. The highest level of educational achievement for 44% of participants was high school or less, with 75% reporting being unemployed. Almost half (45%) reported engaging in less than two hours of structured activity each week. Thirty eight percent of participants reported living in their own apartment, with 25% reporting being homeless and 17% living in a single-room housing unit. The majority of participants (56%) sampled were not satisfied with their housing, and 67% were actively looking for new housing. Sixty percent of participants reported smoking cigarettes daily and 40% reported weekly cannabis use. A total of 11% of the sample reported that they did not have access to clean drinking water; 35% worried that their food would run out, and 47% reported cutting the size of meals due to a lack of money. Conclusion: This study lends evidence towards the circumstances in which patients presenting to the ED with an AMHC live and work. A considerable proportion of patients reported homelessness or being marginally housed, lack access to clean drinking water and sufficient food, and high rates of unemployment. Mitigating the effects of harmful social determinants is critical for optimal health of this population. Future work is needed to clarify the role of the ED in the surveillance, screening, and intervention of SDoH for this vulnerable patient group.
Introduction: In the last year, Canada published its Strategy for Patient-Oriented Research (SPOR) to ensure that patients receive the right treatment at the right time. Approximately, one in five Canadians will experience a mental illness in their life time, with many presenting to the Emergency Department (ED) as their entry point into the system. In order to improve patient outcomes and focus on patient-identified priorities, the aim of this study was to identify the short-term goals of patients with an acute mental health complaint (AMHC) presenting to the ED. Methods: We prospectively recruited a convenience sample of patients presenting to an inner city, academic ED with an annual census of 85,000 visits. Patients provided written informed consent and completed a survey package that included questions about employment intentions and short-term life goals. We collated the goals and used a content analysis to summarize the frequency of themes that emerged. Results: This study reports on the preliminary data from 108 of the targeted 200 patients (mean age 39.7 ±13.6 years; 65% male). A total of 75% of participants reported being unemployed, 84% of whom reported that they would like to gain some form of employment in the near future. Over half the sample (52%) identified that they were not satisfied with their current housing situation. In addition to improving housing and obtaining work, improving mental health (n=34), improving relationships with family or friends (n=27), going back to school (n=22) and managing addiction problems (n=20) were identified as the most common short-term goals. Other goals/priorities included improving physical health, traveling, exercising, and eating better. Conclusion: This study provides new information about the priorities of adults presenting with AMHC to the ED. It also offers insight into how to collaborate with patients to build sustainable, accessible, and coordinated care pathways that can bring about positive changes in their lives. This information can be used to compliment current care for mental health problems, ensuring greater quality, accountability, and continuity of care for this vulnerable patient group.
To investigate socio-economic differences in children’s diet, activity and inactivity and changes in these differences over 4 years during which new policies on food in schools were introduced.
Two cross-sectional surveys in which diet was assessed by FFQ and physical activity and inactivity were assessed by interviewer-administered questionnaire. Socio-economic status was assessed by the area-based Scottish Index of Multiple Deprivation.
Scotland, 2006 and 2010.
Children aged 3–17 years (n 1700 in 2006, n 1906 in 2010).
In both surveys there were significant linear associations between socio-economic deprivation and intakes of energy, non-milk extrinsic sugars (NMES) as a percentage of food energy, sugar-sweetened beverages, confectionery, crisps and savoury snacks and leisure-time screen use (all higher among children in more deprived areas), while intakes of fruit, fruit juice and vegetables showed the opposite trend. In 2010 children in more deprived areas engaged in more physical activity out of school than those in more affluent areas, but between 2006 and 2010 there was an overall reduction in physical activity out of school. There were also small but statistically significant overall reductions in intakes of confectionery, crisps and savoury snacks, energy and NMES and saturated fat as a percentage of food energy, but no statistically significant change in socio-economic gradients in diet or activity between the two surveys.
Interventions to improve diet and physical activity in children in Scotland need to be designed so as to be effective in all socio-economic groups.
The response of the Antarctic ice sheet to climate change over the next 500
years is calculated using the output of a transient-coupled ocean-atmosphere
simulation assuming the atmospheric CO2 value increases up to
three times present levels. The main effects on the ice sheet on this
time-scale include increasing rates of accumulation, minimal surface
melting, and basal melting of ice shelves. A semi-Lagrangian transport
scheme for moisture was used to improve the model’s ability to represent
realistic rates of accumulation under present-day conditions, and thereby
increase confidence in the anomalies calculated under a warmer climate. The
response of the Antarctic ice sheet to the warming is increased accumulation
inland, offset by loss from basal melting from the floating ice, and
increased ice flow near the grounding line. The preliminary results of this
study show that the change to the ice-sheet balance for the
transient-coupled model forcing amounted to a minimal sea-level contribution
in the next century, but a net positive sea-level rise of 0.21 m by 500
years. This new result supercedes earlier results that showed the Antarctic
ice sheet made a net negative contribution to sea-level rise over the next
century. However, the amplitude of the sea-level rise is still dominated In
the much larger contributions expected from thermal expansion of the ocean
of 0.25 m for 100 years and 1.00 m for 500 years.
Diatoms represent a natural source of mesoporous silica whose applications range from biomedical to photonic fields. Porous hierarchically organized micro structures, the biosilica shells called frustules, can be obtained by removal of the organic biological matter from the unicellular living algae. Diatoms frustules have been investigated as scaffold for bone tissue growth taking advantage of their nanostructured surface and of the possibility to chemically modify the biosilica. Here we report on an easy way to calcium-doped biosilica supports for bone tissue regeneration by in vivo feeding the algae. FTIR and EDX analyses confirmed the incorporation of calcium into the mesopouros biosilica. Cell viability studies showed an ameliorative effect on the Saos-2 cells spreading compared with the cells grown on non-doped biosilica supports.
The United States is the third most populous country in the world after the two demographic billionaires, China and India. In 2015, the population of the United States numbered 321 million inhabitants, compared with 1.36 billion in China and 1.29 billion in India (PRB, 2015). When the first census was conducted in the United States in 1790, the population size of the country (as then defined geographically) was just under 4 million, which is about the size today of the metropolitan area of Phoenix, Arizona. In 220 years, the United States has increased tremendously in size, from 3.9 million inhabitants in 1790, to just under 309 million in 2010 (Figure 13.1), to more than 321 million in 2015. In this chapter, I trace the patterns of population growth of the United States from colonial times to the present and then examine some projections of the US population for the future.
HISTORY OF POPULATION CHANGE IN THE UNITED STATES
The Precolonial Period
Estimates for the precolonization period of the size of the population in the land now known as the United States are not easy to obtain, and they vary considerably: “There is probably no single figure that can be accepted as the ‘best’ estimate of the late fifteenth century North American population” (Snipp, 1989: 9). According to Zinn, “The Indian population of [around] 10 million that lived north of Mexico when Columbus came would ultimately be reduced to less than a million. Huge numbers of Indians would die from diseases introduced by the whites. A Dutch traveler in New England wrote in 1656 that ‘the Indians…affirm, that before the arrival of the Christians and before the smallpox broke out amongst them, they were ten times as numerous as they now are, and that their population had been melted down by this disease, whereof nine-tenths of them have died’” (2003: 16).
The number of Native Americans continued to decline over the next centuries and totaled between 125,000 and 150,000 by 1900 (Thornton, 1990: 42). This decline resulted in part from attrition during the continual warfare in which they participated in the defense of their tribal lands, as well as from unusual hardships and, as just noted, from diseases introduced by the European settlers.
You have now read through the first fifteen chapters of this book (I hope you have read all the chapters). You have learned a good deal about population and demography and the world in which we live. You now should know more demography than you did when you first started to read the book. I certainly hope so.
I have discussed the three demographic processes. I have discussed the basic population characteristics, especially age and sex, as well as the family and race/ethnicity. I have discussed population growth as well as population decline. In this final chapter, I look specifically at the population of the Earth, the number of inhabitants on our planet now and in the future. I will inquire how the world population now and in 2100 may be related to other major factors of life on Earth. I will consider the future of the Earth's population from the perspectives of ecology, sociology, and philosophy. Hence, this last chapter has less to do with demography per se and more to do with the influence of population in several other arenas.
In Chapter 12, I considered several different scenarios with respect to the size of the population of our world in the year 2100. I present here as Figure 16.1 the same figure I presented earlier as Figure 12.4. Let me consider the different scenarios to get an idea of what the size of the world's population might be in 2100.
In Chapter 12, I used world population projections prepared recently by the Population Division of the United Nations (2013d). I preferred them over projections prepared by other organizations because, in my view, the UN projections reflect the most reasonable assumptions about future demographic behavior. However, I remind you again, as I have already in Chapter 12, that these are projections about what the population of the world will be in 2100 according to stated assumptions. In no way should they be seen as predictions, nor should they be considered the final word. (Please look back at Chapter 12 for my discussion of the assumptions that guided the development of these UN projections.)
The first “international” migration of humans began around 60,000 years ago, and the migrations continue to this day. Of all the demographic topics presented in this book, none is discussed today by both laypeople and social scientists as frequently and as forcefully as international migration. International migration is migration that occurs between countries. Its dynamics differ from those of internal migration, that is, migration within the geographical boundaries of a single country. Thus, a separate chapter is devoted here to international migration.
I begin this chapter by considering some of the definitions and concepts used in the study of international migration. I next cover world immigration patterns over time. This is followed by a discussion of immigration to the United States. I then consider some of the positive and negative economic issues pertaining to international migration. Considerations of legal and unauthorized immigration are next reviewed. I conclude the chapter with a discussion of the meaning of the concept of zero net international migration.
DEFINITIONS AND CONCEPTS
Similar to the study of internal migration, demographers have developed a fairly standard set of concepts and definitions for studying international migration. The first distinction is between immigration and emigration. Immigration refers to the movement of people to a new country for the purpose of establishing permanent residence; an immigrant is a person who moves to a new country to reside there and crosses an international boundary in doing so. These concepts are analogous in the study of internal migration to in-migration and in-migrant. Conversely, emigration refers to the permanent departure of people from a country; an emigrant is one who migrates away from a country with the intention of establishing a permanent residence elsewhere. The analogous internal migration concepts are out-migration and out-migrant.
In every international migration, a migrant is simultaneously an immigrant and an emigrant. The key element in the definition of an immigrant is the establishment of a permanent residence in the new country. This usually means residence in the destination country for at least one year, and is referred to as long-term immigration.
Whether looking at the planet Earth, Africa, or the United States, it is clear that the population is far from being equally distributed. The distinguished demographer Mark Fossett has written that “structured patterns in spatial distribution are evident from the highest levels of macrospatial scale…to ‘fine-grained’ patterns in metropolitan areas…and nonmetropolitan hinterlands” (2005: 479).
Most know that China's population is more than 1.3 billion, and that the population of the United States is around 321 million. However, many may not be aware that China and the United States are very close in geographic size. China has 9.6 million km2 of surface area compared with the United States with 9.8 million km2. But the populations in both countries are not distributed randomly. Most of the people in both countries live in the eastern regions. However, the distribution in China is far more concentrated in the eastern half of the country, where 90 percent of the population resides. A night-time satellite map for the United States (Figure 14.1) shows that much more than 10 percent of the US population resides in the western half of the country, unlike the situation in China.
In some countries, people are more likely to be rural than urban dwellers. Generally, however, there is an urbanization movement throughout the world: “Without question, the dominant feature of spatial distribution in the United States and other developed countries is the concentration of population in densely settled urban areas” (Fossett, 2005: 479). For that matter, the way in which cities have evolved is a quite interesting phenomenon. In this chapter, I examine how the inhabitants of the world are distributed, and how most of us have become city dwellers rather than cave dwellers, as was the case thousands of years ago.
DISTRIBUTION OF THE POPULATION OF THE WORLD
Only about one-third of the Earth's land is permanently inhabited. Areas such as the Arctic and the Antarctic, as well as the vast deserts such as the Sahara, have very few people. The situation is similar where rugged mountains make it almost impossible for humans to survive. The geographic distribution of the global population is shown in Table 14.1. South Asia (mainly India) and east Asia (mainly China) are the most populated of the world regions, and Oceania (primarily Australia) is the least.
Fertility refers to the actual production of children, which in the strictest sense is a biological process. A zygote is produced when the sperm of a male and the egg of a female are united, and around nine months later a baby is born. Most often in this process, although not always, a man and a woman have sexual intercourse, the woman conceives, and the conception results in a live birth. Even though the production of a child is a biological process, the various activities and events that lead to the act of sexual intercourse and, later, to giving birth, are affected by the social, economic, cultural, and psychological characteristics of the woman and the man, as well as by the environment in which they live. The key to this paradox is that engaging in intercourse, conceiving, and giving birth are themselves behaviors that are influenced by other factors, most of them social and cultural. So while we have no influence at all with regard to the family and parents we receive when we are born, we do have a significant influence on our own fertility. We will decide whether or not we produce children, and, if so, the number and timing of the children produced. That is, whether we decide to engage in sexual intercourse, whether this intercourse results in a conception, and whether a live birth is the outcome are all driven largely by social and cultural considerations.
Fertility may be studied in different ways, one of which is cross-sectionally, that is, at one point in time; a cross-sectional perspective is also known as a period perspective. Were we to study the fertility behavior of women and men in the year 2015, we would develop cross-sectional fertility measures (also called period measures) that would show the number of births to women and men in the calendar year 2015. Most of the fertility measures I present in this chapter are period measures; they refer to a particular time period. A period rate is a rate based on behavior occurring at a particular point or period in time.