Measure Of Population Density Research Articles

What is known, unknown, and needed to be known about damage caused by wild pigs

AbstractDamage assessments provide evidence for initiating and evaluating management programs that protect natural resources and human livelihoods against invasive species. Wild pigs (Sus scrofa) cause extensive damage in their native and non-native ranges, but the extent of current damage and efficacy of management of the damage (i.e., population control of wild pigs, exclusion fencing, etc.) remains poorly described. We conducted a systematic review of physical damage caused by wild pigs to summarize what is known and identify knowledge gaps for damage assessment. Wild pig damage assessments have been overwhelmingly qualitative (84% of studies) and measured differently across studies, which prevents the determination of typical damage amounts to a particular resource and comparison across studies. Key priorities going forward are to standardize damage assessments quantitatively and measure population density (or index of such) of wild pigs concurrently with damage assessments to determine the relationship between damage and population levels. We provide a framework for inferring damage in new areas and assessing the benefits of management—to evaluate and optimize landscape-scale management programs. Overall, we recommend future studies strive for: (1) report the amount of damages in a standardized fashion (e.g., area damaged/area surveyed), (2) evaluate and report the amount of damage relative to the density of wild pigs, and (3) when reporting economic costs of damages incurred and management actions, describe the economic valuation method used along with the year of reference for the valuation. Capturing these elements are necessary steps to predict the benefits of management for an area with particular profile of resources and wild pig density, even in areas where damage assessments are not available. Meeting these criteria with allow for more generalizable results that can inform managers across the nearly global distribution of wild pigs.

Density, structure, growth, and mortality of the population of Ocypode gaudichaudii H. Milne Edwards & Lucas, 1843 (Brachyura, Ocypodidae) in Salaverry, Peru

Abstract The northern coast of Peru includes a series of dissipative desert beaches with varying levels of human impact. One endemic species to these beaches is Ocypode gaudichaudii, which has been shown to be an indicator of ecosystem disturbance. We measured population density, sex ratio, and cephalothorax length of O. gaudichaudii on three beaches near Salaverry between September 2021 and February 2022. The average population density was 0.15 burrows/m2. There was a higher proportion of males (56%); and average cephalothorax length was 28.8 ± 5.6 mm. Population, length, and sex variations during the study may be explained by behaviour of O. gaudichaudii and by temperature-dependent breeding. We also calculated the Von Bertalanffy growth parameters (, , ) and estimated the instantaneous mortality rate to be 0.84/year. These data indicate a high level of disturbance in the ecosystem, with few specimens approaching .

Contributions of mean temperature and temperature variation to population stability and community diversity.

Future climate changes are predicted to not only increase global temperatures but also alter temporal variation in temperature. As thermal tolerances form an important component of a species’ niche, changes to the temperature regime have the capacity to negatively impact species, and therefore, the diversity of the communities they inhabit. In this study, we used protist microcosms to assess how mean temperature, as well as temporal variation in temperature, affected diversity. Communities consisted of seven species in a multitrophic food web. Each ecosystem was inoculated with the same abundances of each species at the start of the experiment, and species densities, Hill's numbers (based on Shannon diversity), the number of extinctions, and the probability the microcosm contained predators were all calculated at the end of the experiment. To assess how mean temperature and temperature fluctuations affect stability, we also measured population densities through time. We found that increased temporal variation in temperature increased final densities, increased Hill's numbers (at low mean temperatures), decreased rates of extinctions, and increased the probability that predators survived till the end of the experiment. Mean temperatures did not significantly affect either the number of extinctions or the probability of predators, but did reduce the positive effect of increased temporal variation in temperature on overall diversity. Our results indicate that climatic changes have the potential to impact the composition of ecological communities by altering multiple components of temperature regimes. However, given that some climate forecasts are predicting increased mean temperatures and reduced variability, our finding that increased mean temperature and reduced temporal variation are both generally associated with negative consequences is somewhat concerning.

THE ENVIRONMENTAL PARAMETERS CONTROLLING THE HABITAT OF INVASIVE ALIEN SPECIES, SPARTINA ALTERNIFLORA IDENTIFIED BY PREDICTIVE MODELING

Spartina alterniflora introduced worldwide has impacted local Japanese ecosystems. Then the management methods of the species are seriously required. In 2019, the invasion of the species was reported at Aichi Prefecture, Japan. The vegetation of the species was grown up to 449 m2 for 5 years. However, the relationship between the habitation of the species and environmental factors remains unclear. Therefore, we made a habitat prediction model using GLM (general linear model) to define the environment of the S. alterniflora habitat of Aichi Pref., incorporating data in 2019. That measured population density, location, ignition loss of physical environmental data, pH, NaCl concentration and altitude over the sea level by us. Our analysis showed that the standardization parameter altitude over the sea level was the main effect in the predictive model (estimate 4.158) and had the greatest absolute value. And the Wald value is significantly large (42.426). Secondary the reciprocal relationship expression between the altitude and pH was high value, 1.007. The species likes the habitat that altitude is high and pH is 7.1-7.3. For the GLM, we made the distribution for the species, the reappearance is well done. Then the avoidance of the species expansion, the bank of the tidal area should erase the higher riverbed

Does BMI predict the early spatial variation and intensity of Covid-19 in developing countries? Evidence from India

This paper studies BMI as a correlate of the early spatial distribution and intensity of Covid-19 across the districts of India and finds that conditional on a range of individual, household and regional characteristics, adult BMI significantly predicts the likelihood that the district is a hotspot, the natural log of the confirmed number of cases, the case fatality rate, and the propensity that the district is a red zone. Controlling for air-pollution, rainfall, temperature, demographic factors that measure population density, the proportion of the elderly, and health infrastructure including per capita health spending and the proportion of respiratory cases, does not diminish the predictive power of BMI in influencing the spatial incidence and spread of the virus. The association between adult BMI and measures of spatial outcomes is especially pronounced among educated populations in urban settings, and impervious to conditioning on differences in testing rates across states. We find that among women, BMI proxies for a range of comorbidities (hemoglobin, high blood pressure and high glucose levels) that affects the severity of the virus while among men, these health indicators are also important, as is exposure to risk of contracting the virus as measured by work propensities. We conduct sensitivity checks and control for differences that may arise due to variations in timing of onset. Our results provide a readily available health marker that may be used to identify and protect especially at-risk populations in developing countries like India.

Where is Everyone? The Importance of Population Density Data: A Data Artefact Study of the Facebook Population Density Map

In this paper, we explore new and traditional approaches to measuring population density, and ways in which density information has frequently been used by humanitarian, private-sector and government actors to advance a range of private and public goals. We explain how new innovations are leading to fresh ways of collecting data—and fresh forms of data—and how this may open up new avenues for using density information in a variety of contexts. Section III examines one particular example: Facebook’s High-Resolution Population Density Maps (also referred to as HRSL, or high resolution settlement layer). This recent initiative, created in collaboration with a number of external organizations, shows not only the potential of mapping innovations but also the potential benefits of inter-sectoral partnerships and sharing. We examine three particular use cases of HRSL, and we follow with an assessment and some lessons learned. These lessons are applicable to HRSL in particular, but also more broadly. We conclude with some thoughts on avenues for future research.

Double integral involving G-function of two variables

In the study of certain boundary value problems integrals are useful with their connections. To obtain expansion formulae it also helps. In the study of integral equation, probability and statistical distribution, integrals are also used. To measure population density within a certain area, we can also use integrals. With integrals we can analyzed anything that changes in time. The object of this research paper is to establish a double integrals involving G-Function of two variables.

Does BMI Predict the Early Spatial Variation and Intensity of Covid-19 in Developing Countries? Evidence from India

This paper studies BMI as a correlate of the early spatial distribution and intensity of Covid-19 across the districts of India and finds that conditional on a range of individual, household, and regional characteristics, adult BMI significantly predicts the likelihood that the district is a hotspot, the natural log of the confirmed number of cases, the case fatality rate, and the propensity that the district is a red zone. Controlling for air-pollution, rainfall, temperature, demographic factors that measure population density, the proportion of the elderly, and health infrastructure including per capita health spending, the proportion of respiratory cases, and the number of viral disease outbreaks in the recent past, does not diminish the predictive power of BMI in influencing the spatial incidence and spread of the virus. The association between adult BMI and measures of spatial outcomes is especially pronounced among educated populations in urban settings, and impervious to conditioning on differences in testing rates across states. We find that among women, BMI proxies for a range of comorbidities (hemoglobin, high blood pressure and high glucose levels) that affects the severity of the virus while among men, these health indicators are less important and exposure to risk of contracting the virus as measured by work propensities is explanatory. We conduct heterogeneity and sensitivity checks and control for differences that may arise due to variations in timing of onset. Our results provide a readily available health marker that may be used to identify especially at-risk populations in developing countries like India.

Quality-adjusted Population Density

Quality-adjusted population density (QAPD) is population divided by land area that has been adjusted for geographic characteristics. We derive weights on these geographic characteristics from a global regression of population density at the quarter-degree level with country fixed effects. We show, first, that while income per capita is uncorrelated with conventionally measured population density across countries, there is a strong negative correlation between income per capita and QAPD; second, that the magnitude of this relationship exceeds the plausible structural effect of density on income, suggesting a negative correlation between QAPD and productivity or factor accumulation; and third, that higher QAPD in poor countries is primarily due to population growth since 1820. We argue that these facts are best understood as results of the differential timings of economic takeoff and demographic transition across countries, and particularly the rapid transfer of health technologies from early to late developers.

Abstract P157: Association of Rurality With Death in Patients With Heart Failure: a Community Study

Background: Previous studies have indicated that living in a rural or non-urban area may be associated with poor health outcomes. However, data on rurality and death in heart failure (HF) are scarce. Methods: Residents from 11 southeast MN counties with a first-ever code for HF (including codes ICD-9 428 and ICD-10 I50) between 1/1/2013 and 12/31/2016 were identified. Resident address was geo-coded and classified according to the Rural-Urban Commuting Area (RUCA) codes, which classifies US census tracts to measure population density, urbanization and daily commuting. Rurality was defined as living in a non-metropolitan area. Cox proportional hazards regression was used to determine the association between living in a rural vs. urban area and death. Results: Among 6,996 patients (mean age 73 years, 52% male), 54% of patients lived in a rural area. These patients were older and had a lower level of educational attainment and comorbidity burden (p<0.001). After a mean (SD) follow-up of 2.9 (1.3) years, 1,856 deaths occurred. Living in a rural area was univariately associated with a higher risk of death (HR 1.20, 95% CI: 1.09-1.31; Table). After adjustment for age, sex, education status and comorbidity burden, rurality remained associated with an increased risk of death (HR 1.15; 95% CI: 1.04-1.27). Conclusions: Among patients with HF, living in a rural area is associated with an increased risk of death. Further study to identify and address the mechanisms through which rural residence influences mortality in patients with HF is needed.

Environmental Correlates to Population Structure and Health of the Rare Piratebush (Buckleya distichophylla) within Poor Mountain Natural Area Preserve, Virginia

Piratebush (Buckleya distichophylla, Santalaceae) is a dioecious, hemi-parasitic shrub endemic to the Blue Ridge Ecoregion of the Appalachian Mountains. The Poor Mountain Natural Area Preserve (PMNAP) in southwestern Virginia protects the densest known population of this rare plant. Permanent transects were set within this natural area to measure population density, size-class structure and health indicators, and to analyze their relationship to ecological parameters. Within PMNAP, there were 9 ± 2 piratebush per 100 m2 of forest floor with a mean size of 4 ± 1 stems of 1.9 ± 0.6 cm diameter at ground height. Individual shrubs grew across a broad range of aspects, slopes (2–50%), and canopy cover (0–100%), exhibiting minimal crown death and a wide range of foliar color value. Weighted size class structure distribution was positively skewed, with low indication of recent seedling recruitment. Observed adventitious vegetative regeneration may mask the frequency of genetically distinct individuals, and indicate less genetic diversity within this population. Weighted size class was positively correlated to forest canopy cover (P < 0.001) and southerly aspect (P = 0.071). Foliar color value was positively correlated with canopy openness (P < 0.001) but neither weighted size class nor plant vigor. This study indicates that successful sexual reproduction within this piratebush population may be rare, and establishes a detailed baseline assessment of the largest extant piratebush population, enabling future study of factors relevant to the long-term viability of this species.

WILLIAM PETTY, THE MULTIPLICATION OF MANKIND, AND DEMOGRAPHIC DISCOURSE IN SEVENTEENTH-CENTURY ENGLAND

AbstractIn the 1650s, after a century of increase, the population of England stopped growing. It was not to increase substantially again before 1750. Over the same interval, and not wholly coincidentally, scholars and theologians were trying to defend the orthodox account of how global population had increased since the Creation and must continue to do so, and the first political arithmeticians were trying to measure and analyse demographic change. This article seeks to throw fresh light on this many-sided discourse by examining William Petty's attempt to write an account of the multiplication of mankind, and the reasons why he failed to complete it. It focuses particularly on Petty's part in developing methods of measuring population density which highlighted the potential for future growth, and on the equally important demonstration by John Graunt that high and rising mortality in cities was hindering population growth in reality. As Petty's cousin Robert Southwell pointed out, Graunt's ‘rule of mortality’ was wholly incompatible with any coherent account of the future multiplication of mankind. At the end of this particular discourse, newly discovered facts about demography triumphed over the presuppositions of divinity.

No effects of increased alcohol availability during adolescence on alcohol-related morbidity and mortality during four decades: a natural experiment

BackgroundA strict high legal age limit for alcohol purchases decreases adolescents’ access to alcohol, but little is known about long-term health effects. The aim was to estimate the effect of...

Land-use strategies to balance livestock production, biodiversity conservation and carbon storage in Yucatán, Mexico.

Balancing the production of food, particularly meat, with preserving biodiversity and maintaining ecosystem services is a major societal challenge. Research into the contrasting strategies of land sparing and land sharing has suggested that land sparing-combining high-yield agriculture with the protection or restoration of natural habitats on nonfarmed land-will have lower environmental impacts than other strategies. Ecosystems with long histories of habitat disturbance, however, could be resilient to low-yield agriculture and thus fare better under land sharing. Using a wider suite of species (birds, dung beetles and trees) and a wider range of livestock-production systems than previous studies, we investigated the probable impacts of different land-use strategies on biodiversity and aboveground carbon stocks in the Yucatán Peninsula, Mexico-a region with a long history of habitat disturbance. By modelling the production of multiple products from interdependent land uses, we found that land sparing would allow larger estimated populations of most species and larger carbon stocks to persist than would land sharing or any intermediate strategy. This result held across all agricultural production targets despite the history of disturbance and despite species richness in low- and medium-yielding agriculture being not much lower than that in natural habitats. This highlights the importance, in evaluating the biodiversity impacts of land use, of measuring population densities of individual species, rather than simple species richness. The benefits of land sparing for both biodiversity and carbon storage suggest that safeguarding natural habitats for biodiversity protection and carbon storage alongside promoting areas of high-yield cattle production would be desirable. However, delivering such landscapes will probably require the explicit linkage of livestock yield increases with habitat protection or restoration, as well as a deeper understanding of the long-term sustainability of yields, and research into how other societal outcomes vary across land-use strategies.

Estimation of aggregation kernels based on Laurent polynomial approximation

The dynamics of particulate processes can be described by population balance equations which are governed by the phenomena of growth, nucleation, aggregation and breakage. Estimating the kinetics of the latter phenomena is a major challenge particularly for particle aggregation because first principle models are rarely available and the kernel estimation from measured population density data constitutes an ill-conditioned problem. In this work we demonstrate the estimation of aggregation kernels from experimental data using an inverse problem approach. This approach is based on the approximation of the aggregation kernel by use of Laurent polynomials. We show that the aggregation kernel can be well estimated from in silico data and that the estimation results are robust against substantial measurement noise. The method is demonstrated for three different aggregation kernels. Good agreement between true and estimated kernels was found in all investigated cases.

The impact of urban regrowth on the built environment

After several decades, an increasing number of European cities have been experiencing population growth after a longer phase of decline. This new growth represents not just a quantitative phenomenon but also has qualitative implications for the urban space and the built environment. A juxtaposition of re- and de-densification, as well as changes in land use, in the form of a small-scale spatial mosaic, can be observed. A crucial factor for estimating the relationship between the built environment and demand for it is population density. Increasing population densities may put pressure on sustaining a certain quality of life and on ecological recovery spaces. In this vein, an indicator concept for re- and de-densification will be applied to the city of Leipzig, one of the most illustrative examples of a regrowing city, in order to shed light on the complex relationship between changing human housing demands and their impact on land use. The concept involves measuring population density. Our study has demonstrated that, although similar density changes can be observed in different periods in different parts of the city, they are dominated by different drivers, leading to the formation of different spatial patterns. The results of our study emphasise that regrowth should be understood as a distinctive process because it is distributed very heterogeneously within the city area, with a variety of spatial effects and impacts. The concept allows us to draw conclusions about processes that mitigate, drive or reinforce regrowth, and therefore contributes to a better understanding of this phenomenon and its implications for land use.

Relationship between built environment attributes and physical function in Japanese community-dwelling older adults.

To explore the relationships between the built environment and older adults' physical function. The present cross-sectional study carried out in 2010-2012 used data drawn from 509 community-dwelling older adults aged 65-86 years living in Kasama City, a Japanese rural region. We evaluated physical function with the following performance tests: grip strength, sit-to-stand, timed up & go and walking speed. Using geographic information systems, we measured population density and the number of destinations related to daily life, community centers, medical facilities and recreational facilities within participants' neighborhoods. After adjusting for potential confounders, we found lower population density was related to poor performance of sit-to-stand and walking speed in both sexes, and grip strength in women (trend P < 0.05). A lower number of daily life-related destinations was related to poor performance of sit-to-stand and walking speed in men, and grip strength and sit-to-stand in women. Similarly, the number of community centers was related to walking speed in both sexes. The number of medical and recreational facilities was also related to some physical performance in both sexes. A lower land use mix score, calculated by principal component analysis, was related to lower performance of sit-to-stand and walking speed in men, and grip strength and sit-to-stand in women. The present study suggests that, although there are some sex differences, low population density, land use mix, and fewer daily life-related destinations, community centers, medical facilities and recreational facilities are negative determinants of physical function. Geriatr Gerontol Int 2017; 17: 382-390.

Mathematical modelling and analysis of an industrial scale evaporative crystallizer producing lactose monohydrate

Lactose is industrially produced by a series of concentration steps to supersaturate the solution allowing crystallization to take place. This papers deals with the operation and analysis of a forced circulation evaporative crystallizer producing pharmaceutical lactose. A mathematical model of the operation of the crystallizer was developed. The model comprises of the mass balance, population balance, nucleation kinetics, growth kinetics and lactose solubility and mutarotation rate expressions. The steady state operation of the crystallizer was analysed from the classical mixed suspension mixed product removal (MSMPR) model perspective. It was found that the crystallizer behaviour deviated from ideal MSMPR behaviour with a steep upward curvature in the population density curve for crystal sizes below 40μm. A size dependent growth (SDG) rate model was used to model the deviation from ideal behaviour. The parameters of the SDG model were estimated by fitting it to the measured population density curve from the crystallizer. The crystallization kinetic parameters like growth and nucleation rate constants were then estimated by fitting the simulated trends to the measured date. The model showed that the average crystal size follows a transient decaying dynamics before settling down to a constant value. This was reflected in the actual data collected from the crystallizer. The transient dynamics disappeared from the model results when a simple size independent growth model was used.

The physics of bacterial decision making.

The choice that bacteria make between sporulation and competence when subjected to stress provides a prototypical example of collective cell fate determination that is stochastic on the individual cell level, yet predictable (deterministic) on the population level. This collective decision is performed by an elaborated gene network. Considerable effort has been devoted to simplify its complexity by taking physics approaches to untangle the basic functional modules that are integrated to form the complete network: (1) A stochastic switch whose transition probability is controlled by two order parameters—population density and internal/external stress. (2) An adaptable timer whose clock rate is normalized by the same two previous order parameters. (3) Sensing units which measure population density and external stress. (4) A communication module that exchanges information about the cells' internal stress levels. (5) An oscillating gate of the stochastic switch which is regulated by the timer. The unique circuit architecture of the gate allows special dynamics and noise management features. The gate opens a window of opportunity in time for competence transitions, during which the circuit generates oscillations that are translated into a chain of short intervals with high transition probability. In addition, the unique architecture of the gate allows filtering of external noise and robustness against variations in circuit parameters and internal noise. We illustrate that a physics approach can be very valuable in investigating the decision process and in identifying its general principles. We also show that both cell-cell variability and noise have important functional roles in the collectively controlled individual decisions.

Relationship between habitat characteristics and densities of southern Idaho ground squirrels

Many wildlife species living in sagebrush-steppe habitats of the Intermountain West of the United States have experienced population declines. Effective management of such species, especially restoration efforts, is contingent on understanding relationships between habitat characteristics and population densities of the target species. Unfortunately, even such basic information is often lacking. The goal of this 2-year study was to determine the relationship between southern Idaho ground squirrel (Urocitellus endemicus) population densities and habitat variables: soils (texture), topography (slope, aspect), and vegetation (canopy cover, species diversity). We measured population density indirectly through burrow entrance counts and categorized them into high-burrow and low-burrow densities. We used logistic regression and Akaike's Information Criterion to identify a best subset of models. We employed model averaging and calculated odds ratios for averaged parameter estimates found in the best models. A high density of burrows was associated with greater percentages of silt; east-facing aspects; greater plant species diversity; and greater cover of perennial grasses, perennial grasses and forbs, and native perennial forbs. Low burrow density was associated with greater percentages of sand; south-facing aspects; greater cover of exotic annuals; and lesser plant species diversity. Management of southern Idaho ground squirrel habitat should focus on protecting areas with existing native vegetation and restoring native, perennial vegetation in areas that are infested with exotic annuals, especially in areas possessing suitable soil types and topographic features. © 2013 The Wildlife Society.