To see the other types of publications on this topic, follow the link: Population control.
Dissertations / Theses on the topic 'Population control'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Population control.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Ng, Wing-fai. "Density control in Hong Kong /." [Hong Kong : University of Hong Kong], 1991. http://sunzi.lib.hku.hk/hkuto/record.jsp?B1311735X.
Full text
2
Landolt, Laura K. "Norms, population control, USAID and Egypt." Diss., The University of Arizona, 2004. http://hdl.handle.net/10150/290116.
Full textAbstract:
This dissertation examines the conceptualization, promotion and diffusion of the norm of population control at international and domestic levels, as well as adoption and implementation in Egypt. It also offers a critique of mainstream constructivism, an increasingly popular analytical approach to norm diffusion. Constructivists present convincing evidence that nonstate actors change state preferences through the promotion and diffusion of norms, or "shared expectations about appropriate behavior held by a community of actors" (Finnemore 1996, 22). To emphasize the independent influence of social factors, and to downplay material factors, however, constructivists select cases in which norm diffusion occurred before state sponsorship. Constructivist research answers the question, 'How are norms diffused in the absence of material constraint?' Aside from its censorship of material factors, additional constructivist shortcomings include its proclivity for examining only liberal or progressive norms, and its inattention to domestic political process and elites' broader decision-making options. This dissertation demonstrates that diffusion of the norm of population control depended on a combination of material and social factors related to an alliance among strange bedfellows, namely the United States and allied donors and INGOs, UN agencies, populationist and liberal feminist NGOs, and international financial institutions. In this case, the 'norm cascade' of formal state adoptions of population control followed formal social and material support by the United States and, subsequently, the United Nations. This research seeks to demonstrate that relationships of social and material inequality strongly condition the norms that are selected or rejected by international society and states, and the ways in which opponents conceptualize and mobilize for change. The case of population control suggests interesting answers to a different question, namely: How and why are certain international norms, and not others, successfully promoted, diffused and adopted by states? This dissertation also examines the mechanics of norm mutation, or efforts by the international women's health movement to substitute the original population control paradigm, family planning, with the new reproductive health paradigm. This new paradigm was adopted at the 1994 UN International Conference on Population and Development (ICPD), and the final chapter examines the current prospects for paradigm change in Egypt.
3
Conway, Michael. "Improving transgenic approaches to mosquito population control." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:44ba0b39-cded-4e96-a796-570affd53de0.
Full textAbstract:
The disease vectors Aedes aegypti and Aedes albopictus are serious and growing threats to global health. As vectors of the arboviruses dengue fever and chikungunya, these mosquitoes are responsible for hundreds of millions of cases and thousands of deaths each year. Absent specific treatments or vaccines, effective control of mosquito populations remains the only option for tackling a growing public health challenge. More effective control tools are urgently needed. Recently, a novel approach to pest population control has been developed based on the release of insects carrying a repressible, dominant lethal allele. This approach has achieved dramatic reductions in Ae. aegypti populations in regulated open field experiments. Despite this success, there remains scope to improve upon the current technology. It is proposed that an 'ideal' strain would combine the following features: (i) repressible lethality in late juvenile phases; (ii) a mechanism for removing females at an early developmental stage in the release generation; and (iii) orthogonal expression control mechanisms allowing both these systems to be combined in a single strain. This thesis describes research undertaken in pursuit of a 'next generation' strain. Two novel promoters from putative Osiris genes have been identified which confer a 102-103 – fold up-regulation in transgene expression specific to late pupal stages. One of these 'Osiris' promoters has been used to develop transgenic Aedes aegypti strains. 5 lines showed pupal-specific lethality of 98-100% penetrance, which was repressed in the presence of tetracycline. An Ae. albopictus orthologue of the sex-determining gene doublesex (dsx) has been isolated and characterised and a female-specific expression system developed. Transgenic lines show female-specific expression of a transgene; however, there remains some 'leaky' expression in male insects. Finally, a potential expression control tool based on an auxin-inducible expression system has been investigated. 11 different transgenic lines were developed based on three different construct designs. None showed auxin-inducible expression of a transgene.
4
Alton, Michelle. "Control of the oocyte population in mouse ovaries." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=81585.
Full textAbstract:
Oocyte loss and meiotic prophase progression was studied in XY sex-reversed and XO female mice, two mouse models that lack pairing between their sex chromosomes. An arrest at the pachytene stage of meiosis was not observed, nor was a significant loss of oocytes at this stage compared to normal XX control mice. Thus, it was concluded that a pairing checkpoint either does not exist in oocytes or is not as stringent as the one observed in males.The effect of mutating the pro-apoptotic Bax molecule was studied at three distinct ages corresponding to the time when female germ cells are premeiotic, in meiotic prophase, and arrested in dictyotene. Although it appeared that more germ cells were retained in the Bax homozygous mutant compared to the wild-type and heterozygous mice at 18.5 dpc, by 24.5 dpc all of the mice possessed similar numbers of germ cells. These results indicate a role for Bax in germ cell death but also support the idea that an alternative pathway can compensate for the elimination of this molecule.
5
Coats, Rachel. "Fine motor control in a healthy aging population." Thesis, University of Reading, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.515882.
Full text
6
Slocombe, Tom. "Control of plasma cell generation and population dynamics." Thesis, University of Edinburgh, 2012. http://hdl.handle.net/1842/7646.
Full textAbstract:
Plasma cells, the effector stage of the B cell compartment, secrete large amounts of antibody. These cells arise in two waves during T-‐dependent immune responses; an early wave (extrafollicular plasma cells) generate low-‐affinity antibodies that provide a first line of defence against invading pathogens. Later, plasma cells emerge from the germinal centre reaction and secrete high-‐affinity antibodies. These plasma cells have the capacity to migrate to the bone marrow, where they become established as long-‐lived, non-‐dividing plasma cells. Here, I show that plasma cells found in the bone marrow of young (5-‐week-‐old) mice had a turnover comparable to that seen in the spleen. Long-‐lived plasma cells accumulated over the ensuing weeks until they came to dominate the bone marrow plasma cell compartment by 30-‐weeks of age. This accumulation required MHC II, CD40 and a normal B cell receptor repertoire, implying that these cells are generated during T-‐dependent immune responses. Secondly, I determine the signalling pathways required to generate splenic extrafollicular plasma cell responses in the T-‐dependent response to sheep red blood cells (SRBC) and in bacterial infection with Salmonella. While T cell help, antigen recognition through the B cell receptor (BCR) and TLR signalling were required for maximal plasma cell responses to SRBC, in Salmonella infection TLR signalling was required for day 4 IgM plasma cell responses, whereas class-‐ switched responses at day 8 required T cell help. The extrafollicular responses generated in Salmonella persisted for around 35 days, far greater than the 2-‐3 days seen following SRBC immunisation. This was likely due to both antigen persistence causing the generation of new plasma cells, and the induction of cellular populations that produced the plasma cell survival factor APRIL. Thirdly, I document the failure of chronic immune responses to generate long-‐ lived bone marrow plasma cells. This was accomplished by measuring the generation and survival of bone marrow plasma cells in models of rheumatoid arthritis (K/BxN mice), long-‐term infection with Salmonella, and a direct comparison between acute and chronic delivery of the T-‐dependent protein antigen NP-‐KLH. In all cases, chronic immune responses generated few bone marrow plasma cells, ostensibly due to a failure to migrate to the organ. Finally, I show the depletion of bone marrow plasma cell populations caused by inflammatory episodes. This was observed in Salmonella infection, Schistosoma mansoni infection and immunisation with protein antigen plus adjuvants. This depletion mediated a reduction of antigen-‐specific bone marrow plasma cell populations and serum antibody previously established by the secondary response to NP-‐KLH.
7
Biddulph, Matthew John. "Population Control in Insurgencies: Tips for the Taliban." Ohio University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1319657998.
Full text
8
Lloyd, Stephanie Jane. "Robust and optimal control of disturbed population dynamics." Thesis, University of Exeter, 2015. http://hdl.handle.net/10871/20860.
Full textAbstract:
We use control theory to explore management of populations affected by disturbances and uncertainty. We consider five related topics. Chapter 2 uses linear programming to find optimal translocation strategies between wild and captive populations. To allow comparison of the solutions we classify the optimal strategy depending on which stage classes are kept in captivity. We find depending on species, that different stages are targeted when the resource available is limited. In Chapter 3 we use linear programming to create management strategies for an invading population affected by disturbance. For a sinusoidal disturbance, the final population with control is bounded between a transfer function approximation and a feedback control solution. Then we assume worst case disturbance, which creates a 2-player game. In this linear programming context then it is possible that minimax < maximin. Chapter 4 considers a 2-player linear-quadratic problem and introduces the use of disturbance attenuation into ecology. Disturbance attenuation shows how a disturbance is amplified or attenuated by the system. In Chapter 5 we consider an invading population, and we explore the effect that stochasticity has on the relationship between Allee effect and population inertia needed for successful invasion. We find that for small population densities, then demographic stochasticity dramatically reduces the likelihood of invasion and survival of the resident.
9
Bolin, Nicholas John. "Indian and American Demography, Expertise, and the Family Planning Consensus: 1930-1970." Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/95816.
Full textAbstract:
Indian population policy in the twentieth century was shaped by a blend of unique Indian concerns about population growth, legacies of British colonialism, and American foreign aid. This blend of influences resulted in the first national family planning program in the world.Master of Arts
10
Bycroft, Clare. "Genomic data analyses for population history and population health." Thesis, University of Oxford, 2017. https://ora.ox.ac.uk/objects/uuid:c8a76d94-ded6-4a16-b5af-09bbad6292a2.
Full textAbstract:
Many of the patterns of genetic variation we observe today have arisen via the complex dynamics of interactions and isolation of historic human populations. In this thesis, we focus on two important features of the genetics of populations that can be used to learn about human history: population structure and admixture. The Iberian peninsula has a complex demographic history, as well as rich linguistic and cultural diversity. However, previous studies using small genomic regions (such as Y-chromosome and mtDNA) as well as genome-wide data have so far detected limited genetic structure in Iberia. Larger datasets and powerful new statistical methods that exploit information in the correlation structure of nearby genetic markers have made it possible to detect and characterise genetic differentiation at fine geographic scales. We performed the largest and most comprehensive study of Spanish population structure to date by analysing genotyping array data for ~1,400 Spanish individuals genotyped at ~700,000 polymorphic loci. We show that at broad scales, the major axis of genetic differentiation in Spain runs from west to east, while there is remarkable genetic similarity in the north-south direction. Our analysis also reveals striking patterns of geographically-localised and subtle population structure within Spain at scales down to tens of kilometres. We developed and applied new approaches to show how this structure has arisen from a complex and regionally-varying mix of genetic isolation and recent gene-flow within and from outside of Iberia. To further explore the genetic impact of historical migrations and invasions of Iberia, we assembled a data set of 2,920 individuals (~300,000 markers) from Iberia and the surrounding regions of north Africa, Europe, and sub-Saharan Africa. Our admixture analysis implies that north African-like DNA in Iberia was mainly introduced in the earlier half (860 - 1120 CE) of the period of Muslim rule in Iberia, and we estimate that the closest modern-day equivalents to the initial migrants are located in Western Sahara. We also find that north African-like DNA in Iberia shows striking regional variation, with near-zero contributions in the Basque regions, low amounts (~3%) in the north east of Iberia, and as high as (~11%) in Galicia and Portugal. The UK Biobank project is a large prospective cohort study of ~500,000 individuals from across the United Kingdom, aged between 40-69 at recruitment. A rich variety of phenotypic and health-related information is available on each participant, making the resource unprecedented in its size and scope. Understanding the role that genetics plays in phenotypic variation, and its potential interactions with other factors, provides a critical route to a better understanding of human biology and population health. As such, a key component of the UK Biobank resource has been the collection of genome-wide genetic data (~805,000 markers) on every participant using purpose-designed genotyping arrays. These data are the focus of the second part of this thesis. In particular, we designed and implemented a quality control (QC) pipeline on behalf of the current and future use of this multi-purpose resource. Genotype data on this scale offers novel opportunities for assessing quality issues, although the wide range of ancestral backgrounds in the cohort also creates particular challenges. We also conducted a set of analyses that reveal properties of the genetic data, including population structure and familial relatedness, that can be important for downstream analyses. We find that cryptic relatedness is common among UK Biobank participants (~30% have at least one first cousin relative or closer), and a full range of human population structure is present in this cohort: from world-wide ancestral diversity to subtle population structure at sub-national geographic scales. Finally, we performed a genome-wide association scan on a well-studied and highly polygenic phenotype: standing height. This provided a further test of the effectiveness of our QC, as well as highlighting the potential of the resource to uncover novel regions of association.
11
Pijls, C. F. N. R. M. J. "Population genetics of fungicide resistance in Septoria tritici." Thesis, University of Reading, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308103.
Full text
12
Smith, G. C. "Urban foxes (Vulpes vulpes) and rabies control." Thesis, University of Bristol, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234565.
Full text
13
Gurney, Joanne Elizabeth. "The use of semiochemicals for vertebrate pest population control." Thesis, University of York, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.273829.
Full text
14
Usborne, Cornelie. "Fertility control and population policy in Germany 1910-1928." Thesis, Open University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329908.
Full text
15
White, Adam Edward. "An adaptive strategy to control the space debris population." Thesis, University of Southampton, 2014. https://eprints.soton.ac.uk/377012/.
Full textAbstract:
As a result of the last 60 years of satellite launches, a significant amount of space debris has been generated in Earth orbit. Growing consensus amongst experts over the last decade, has suggested that removing existing debris, alongside mitigation efforts, can assist in controlling the size of the low Earth orbit (LEO) population. However, no objective or long-term strategy exist to ensure the most effective use of active debris removal (ADR). The way we utilise near-Earth space, and the way the space environment will behave in the future will directly affect the number of debris objects required to be removed. This then, makes it difficult to identify any potential future ADR strategy that will perform effectively in all possible future cases. This thesis explores a novel adaptive strategy that determines how many debris objects should be removed to control the size of the LEO debris population. The strategy adapts and adjusts the number of removals performed by ADR in response to the evolution of the debris population. The framework for the strategy was inspired by the methods incorporated in adaptive management and control engineering. The University of Southampton’s Debris Analysis and Monitoring Architecture to the Geosynchronous Environment (DAMAGE) model was used to represent the space environment, whilst a new debris model entitled the Computational Adaptive Strategy to Control Accurately the Debris Environment (CASCADE) was used to predict the evolution of DAMAGE, and required removal rate. Predictions using DAMAGE were run under a variety of launch, explosion, mitigation and solar activity for both the ≥10 cm and ≥5 cm LEO populations. Two key parameters of the adaptive strategy were also investigated: modifying the frequency of implementation and exploring different high-level objeives for the strategy. Using the adaptive strategy increased the probability of achieving its objective and required fewer removals, as each prediction had a bespoke number of removals. On average, 3.1 removals (standard deviation: 1.2) were required to provide an 88% probability in preventing the growth of the ≥10 cm LEO population. Whereas, implementing realistic variations in launch, explosion, mitigation and solar activity, on average, 6.3 removals (standard deviation: 6.8) were required to prevent the growth of the ≥5 cm LEO population with 76% confidence. This compared with a “traditional” strategy of removing five objects per year that only provided 49% confidence. This approach then, represents a rational method to calculate the number of removals required to ensure the future sustainability of outer space activities.
16
Potireddy, Santhi. "TRANSLATIONAL CONTROL OF MATERNAL mRNA POPULATION IN MOUSE EMBRYOS." Diss., Temple University Libraries, 2010. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/67111.
Full textAbstract:
BiochemistryPh.D.
Early mammalian development before the oocyte-to-embryo transition is under 'maternal control' from factors deposited in the cytoplasm during oocyte growth, synthesized independent of de novo transcription. Maternal mRNAs encode proteins necessary for early embryo development. Two elements in the mRNA 3’untranslated region (UTR), the cytoplasmic polyadenylation element (CPE) and the hexanucleotide (AAUAAA) are involved in the control of translation of specific mRNAs during meiotic maturation. Despite advances in understanding the translational regulation during meiotic maturation, regulation at the 1-cell stage has not been explained. More studies are required to explain this complex mechanism of temporal mRNA recruitment after fertilization. Maternal mRNAs translated at different stages were examined to understand how specific maternal mRNAs are synthesized and stored, what are these maternal mRNAs, which maternal mRNAs are translated, and how these maternal mRNAs are temporally regulated. Polysomal mRNAs from eggs and 1-cell embryos were analyzed by microarray analysis and this indicated that temporally significant biological activities were encoded by mRNAs recruited at different stages of development. The mRNAs recruited in eggs were involved in homeostasis and transport mechanisms and those recruited in zygotes were involved in biosynthesis and metabolic activities. These data indicated that there is a temporal regulation of maternal mRNAs to meet the different biological requirements of the embryos. After the identification of temporally translated mRNAs, experiments were performed to understand the mechanism underlying temporal translation. The prevalence of the CPE differed between the two mRNA populations translated i.e., egg and 1-cell stage polysomal mRNAs. CPEs were present in ~53% of transcripts at the 1-cell stage compared to ~86% at the MII stage. This indicated that novel motifs other than CPEs regulate translation of mRNAs at the 1-cell stage. Truncation and deletion experiments were conducted using chimeric mRNAs based on one mRNA that was enriched in the 1- cell polysomes (Bag4). These experiments led to the identification of two regulatory regions that control translation at the 1-cell stage, an 80 nt region and a 43 nt region with different regulatory motifs. The 80 nt region is involved in activation of translation and the 43 nt region has an inhibitory effect on translation at the MII and early 1-cell stage. These results provide a detailed picture of how specific maternal mRNAs are prevented from undergoing translation at the MII stage and how the effect of inhibition is eliminated by the late 1-cell stage.
Temple University--Theses
17
DOTTOR, ALBERTO. "MOTOR CONTROL OF THUMB-INDEX SYSTEM IN HEALTHY POPULATION." Doctoral thesis, Università degli studi di Genova, 2021. http://hdl.handle.net/11567/1057767.
Full textAbstract:
Thumb and Index fingers are involved in many daily tasks, it is understandable how injuries, musculoskeletal, rheumatologic, and neurological diseases could affect hand function causing severe disability. The evaluation of motor control deficits of the thumb-index system is necessary to identify impairments and to propose specific therapeutic or surgical proposes.
Pinch maximal voluntary contraction is the most investigated parameter, it is a valid estimator of general hand function. However, thumb and index are rarely involved at their maximal contraction, usually they are used in precision pinches at low submaximal forces exerted for a short-to-long time. For this reason other parameters must be investigated.
In this dissertation, a multiparametric evaluation of thumb-index system was proposed. The battery of tests consisted of the maximal voluntary contraction (MVC) of pinch grip (TP, tip pinch and PP, palmar pinch) and of the opposite movement (E, extension of thumb and index), the endurance (SC, sustained contraction), the accuracy and precision of pinch force in a pinch and release task (DC, dynamic contraction) and the force coordination between hands in a bimanual simultaneous task (BSC, bimanual strength coordination).
The tasks were measured with a measurement system consisted of two pinch gauges, connected to a PC, the visual feedback was displayed on a monitor through the graphical user interface of an ad-hoc developed software.
To be usable in the clinical context, it is important to check the reliability of the tasks and collecting data in healthy samples permits on the one hand to analyse how values changes as function of anthropometric variables, hand dominance, dexterity, and on the other hand to define the reference values to compare pathological populations.
Therefore this dissertation was conducted through test-retest reliability studies and cross-sectional studies to establish normative data of PP, TP, E MVCs, SC, DC and BSC in the Italian population.
All the tasks proved reliable and consistent, MVC and SC showed high reliability, DC and BSC reliability was lower but clinically suitable.
Strength, analysed through PP, TP, E MVCs, declined in line with the normal process of aging that also entails muscle fibers and the reduction of daily activities in older adults. In relative terms, E-MVC showed the highest strength loss in the over 75y. SC showed similar values in all age groups, variables of DC and BSC showed instead large effect related to age-decline. Women performed better than men only in SC, in MVC, DC and BSC men excelled. A hand dominance effect emerged only in TP and PP MVC. Correlations between tasks were very low to low, suggesting that different constructs were measured by the tasks.
This Ph.D. project proposed novel tasks to evaluate pinch motor control which were showed reliable in healthy people and their normative data were obtained, representing a useful aid in the clinical field.
The results become a starting point for future studies to highlight impairments of the thumb-index system in different neurological and musculoskeletal disorders and to guide the rehabilitation and the therapeutic intervention.
18
Ward, Alastair Iain. "The ecology and sustainable management of roe deer (Capreolus capreolus) in multiple use forestry." Thesis, University of York, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.247728.
Full text
19
Ellender, Tommas Jan. "Perisomatic-targeting interneurons control the initiation of hippocampal population bursts." Thesis, University of Oxford, 2009. http://ora.ox.ac.uk/objects/uuid:9c9c34af-a20f-4c9c-9cb3-85f110a1e38e.
Full textAbstract:
Replay of spike sequences can be seen during sharp wave – ripple population burst activity in the hippocampus. It is thought that this activity, which occurs during rest and sleep, is involved in memory consolidation. The cellular mechanisms underlying the initiation of these replay events are not well understood. To investigate this, a hippocampal slice model, showing spontaneous sharp wave – ripple activity, and a combination of planar multi-electrode array recordings and whole-cell patch-clamp recordings of anatomically identified hippocampal neurons were used. Firstly, the spatial and temporal profile of sharp waves in vitro was analysed in detail. Sharp waves were generated by changing subpopulations of pyramidal neurons in the CA3 region and had characteristics similar to those found in vivo. Secondly, four major receptor types present in hippocampal CA3, namely NMDA, AMPA, GABAA and GABAB receptors, were investigated for their involvement in sharp wave generation. Surprisingly, not only AMPA receptor-mediated events, but also phasic GABAA receptor-mediated inhibition, were necessary for sharp wave generation. Thirdly, single perisomatic-targeting interneurons were activated. This experiment showed that induced spiking activity of an individual perisomatic-targeting interneuron can both suppress and subsequently enhance local sharp wave generation. Spiking activity of other neuron types (i.e. pyramidal neurons, dendritic-targeting interneurons and interneuron-selective interneurons) had no significant effect on sharp wave incidence. Finally, it is suggested that this post-inhibitory enhancement of sharp wave generation can be mediated by a transient increase in the ratio of excitation to inhibition in the local network. In conclusion, these results suggest a new role for perisomatic-targeting interneurons in controlling the local initiation of sharp waves by selectively suppressing and subsequently enhancing recruitment of a subpopulation of pyramidal neurons. These results further imply that interneurons may play an integral part in the local information processing that takes place in the hippocampal network.
20
Brown, Malcolm. "Rats in an agricultural landscape : population size, movement and control." Thesis, University of Leicester, 2007. http://hdl.handle.net/2381/8193.
Full textAbstract:
This research investigated the effects of coordinating rodent control across areas up to 400 ha, using conventional and alternative strategies, to see if it was possible to reduce rat numbers and to keep them at a lower level compared with uncoordinated control. The aims were to reduce the rat numbers, reduce the amount of rodenticide used over time and to reduce the risk of secondary poisoning of non-target animals. Rodenticide loads in rat carcasses were investigated using historical and new samples from Berkshire, Leicestershire and Yorkshire in order to quantify risk to non-target predators of rats. Movement was also studied to see if rats were moving into farmyards in the autumn and out in the spring as is generally assumed. Analysis of radio-tracking data showed that the majority of rats tracked stayed within a small home range, two moved and stayed away from the trap site and only one moved into a farmyard. Analysis of the movement of the rats caught in traps showed that the movement towards and away from farms was in roughly equal numbers. The rodenticide analysis showed that rats from areas of rodenticide resistance carried a far greater body load of poison than those from non-resistance areas. Thus resistance increases the risk of a predator or scavenger of rats ingesting a lethal dose more quickly in areas of rodenticide resistance. The coordinated rat control was broadly successful over a period of two to three years. Rat numbers varied greatly between Yorkshire and Leicestershire, with Yorkshire having the larger numbers. Rat control in the coordinated areas showed a decreasing trend over the period. Bait take also generally showed a decline over the period. The results revealed an apparent delayed synchrony in rat numbers between coordinated and uncoordinated areas in Yorkshire that requires further investigation to explain.
21
Vollmer, Ulrich [Verfasser]. "Control of Crystallization Processes Based on Population Balances / Ulrich Vollmer." Aachen : Shaker, 2005. http://d-nb.info/1186577274/34.
Full text
22
Lintott, Rachel A. "Mathematical modelling of population and disease control in patchy environments." Thesis, University of Stirling, 2014. http://hdl.handle.net/1893/21173.
Full textAbstract:
Natural populations may be managed by humans for a number of reasons, with mathematical modelling playing an increasing role in the planning of such management and control strategies. In an increasingly heterogeneous, or `patchy' landscape, the interactions between distinct groups of individuals must be taken into account to predict meaningful management strategies. Invasive control strategies, involving reduction of populations, such as harvesting or culling have been shown to cause a level of disturbance, or spatial perturbation, to these groups, a factor which is largely ignored in the modelling literature. In this thesis, we present a series of deterministic, differential equation models which are used to investigate the impact of this disturbance in response to control. We address this impact in two scenarios. Firstly, in terms of a harvested population, where extinction must be prevented whilst maximising the yield obtained. Secondly, we address the impact of disturbance in an epidemic model, where the aim of the control strategy is to eradicate an endemic pathogen, or to prevent the invasion of a pathogen into a susceptible population. The movement of individuals between patches is modelled as both a constant rate, and a function which is increasing with population density. Finally, we discuss the 'optimal' control strategy in this context. We find that, whilst a population harvested from a coupled system is able to produce an inflated yield, this coupling can also cause the population to be more resistant to higher harvesting efforts, increasing the effort required to drive the population to extinction. Spatial perturbation raises this extinction threshold further still, providing a survival mechanism not only for the individuals that avoid being killed, but for the population as a whole. With regards to the eradication of disease, we show that disturbance may either raise or lower the pathogen exclusion threshold depending on the particular characteristics of the pathogen. In certain cases, we have shown that spatial perturbation may force a population to be susceptible to an infectious invasion where its natural carrying capacity would prevent this.
23
Cloutier, Daniel. "Population dynamics of yellow nutsedge (Cyperus esculentus L.)." Thesis, McGill University, 1986. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=74003.
Full text
24
Adebiyi, Ayodeji O. "Mathematical modeling of the population dynamics of tuberculosis." University of the Western Cape, 2016. http://hdl.handle.net/11394/4928.
Full textAbstract:
>Magister Scientiae - MScTuberculosis (TB) is currently one of the major public health challenges in South Africa, and in many countries. Mycobacterium tuberculosis is among the leading causes of morbidity and mortality. It is known that tuberculosis is a curable infectious disease. In the case of incomplete treatment, however, the remains of Mycobacterium tuberculosis in the human system often results in the bacterium developing resistance to antibiotics. This leads to relapse and treatment against the resistant bacterium is extremely expensive and difficult. The aim of this work is to present and analyse mathematical models of the population dynamics of tuberculosis for the purpose of studying the effects of efficient treatment versus incomplete treatment. We analyse the spread, asymptotic behavior and possible eradication of the disease, versus persistence of tuberculosis. In particular, we consider inflow of infectives into the population, and we study the effects of screening. A sub-model will be studied to analyse the transmission dynamics of TB in an isolated population. The full model will take care of the inflow of susceptibles as well as inflow of TB infectives into the population. This dissertation enriches the existing literature with contributions in the form of optimal control and stochastic perturbation. We also show how stochastic perturbation can improve the stability of an equilibrium point. Our methods include Lyapunov functions, optimal control and stochastic differential equations. In the stability analysis of the DFE we show how backward bifurcation appears. Various phenomena are illustrated by way of simulations.
25
Mortimer, Simon Richard. "The control of population size of sparse perennials in chalk grassland." Thesis, University of Cambridge, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319820.
Full text
26
Brak, Bastiaan. "Modelling weed population dynamics : impact of cultural control and climate change." Thesis, University of Warwick, 2009. http://wrap.warwick.ac.uk/2743/.
Full textAbstract:
Over the last three decades, concern about food safety and the management of natural resources has increased. Instigated by the previous EU pesticide review, (EU 91/414) carrot growers in particular have been hit by the revocation of several post-emergence herbicides. There is real concern among growers that this may impair profits. To identify alternative weed control strategies, a modelling framework capable of simulating the impact of alternative weed management strategies on long-term weed population dynamics, was proposed. Scentless mayweed (Tripleurospermum inodorum) was chosen as model weed species. The system represented in ECOSEDYN (Effects of Cultural control and climate On SEedbank DYN For each component model in ECOSEDYN the literature was reviewed to identify the best mathematical representation and then the model was parameterised. To improve accuracy of model projections and address gaps in knowledge, field experiments were conducted in two areas: soil cultivation, and plant growth and reproduction. The results of the cultivation experiments revealed that key assumptions in models for weed seed re-distribution are incorrect. The experiments focusing on plant growth and reproduction resulted in a novel approach to the modeling of biomass increase, flowering and seed shedding where the different processes were quantitatively and temporally linked using Beta functions. amics), comprises a six-year crop rotation: one year of carrot and five years winter wheat and repeated four times. The weed management strategies consist of combinations of cultural control measures (sowing time and crop maturity time). In addition, the interaction of climate with the cultural control measures was assessed by implementing two future climate scenarios, (‘No change’ vs ‘Heating up’) based on weather data over the last 18 years. The results of the ECOSEDYN simulations showed that, regardless of the prevailing climate, choosing a fast maturing carrot cultivar is by far the most important factor in maintaining the weed seedbank low. In addition, the risk for higher seedbank levels in the long-term under ‘Heating up’ climate is largest if carrot is continuously sown late.
27
Liu, Xiaoshi Melody, and 劉曉詩. "Case-control study of coronary heart disease in YS country population." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2008. http://hub.hku.hk/bib/B41711233.
Full text
28
Amos-Landgraf, James. "A HUMAN POPULATION STUDY OF THE GENETIC CONTROL OF X-INACTIVATION." Case Western Reserve University School of Graduate Studies / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=case1089861669.
Full text
29
Coates, James W. "Rat Population Assessment and Control in Eastern Suburbs of Cleveland, Ohio." Cleveland State University / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=csu1265291743.
Full text
30
Klaimanee, Wiphusana. "The need to improve population and resource control in Thailand's counterinsurgency." Thesis, Monterey, Calif. : Naval Postgraduate School, 2008. http://edocs.nps.edu/npspubs/scholarly/theses/2008/Dec/08Dec%5FKlaimanee.pdf.
Full textAbstract:
Thesis (M.S. in Defense Analysis)--Naval Postgraduate School, December 2008.Thesis Advisor(s): Borer, Douglas ; Lober, George. "December 2008." Description based on title screen as viewed on January 30, 2009. Includes bibliographical references (p. 113-115). Also available in print.
31
Liu, Xiaoshi Melody. "Case-control study of coronary heart disease in YS country population." Click to view the E-thesis via HKUTO, 2008. http://sunzi.lib.hku.hk/hkuto/record/B41711233.
Full text
32
So, Chin-Hung. "Economic development, state control, and labour migration of women in China." Thesis, University of Sussex, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361403.
Full text
33
Choquenot, David, and n/a. "Feral donkeys in northern Australia : population dynamics and the cost of control." University of Canberra. Applied Science, 1988. http://erl.canberra.edu.au./public/adt-AUC20061113.145306.
Full textAbstract:
(1) Rate of increase was measured for feral donkey
populations in parts of northern Australia as the average
exponential rate of increase, r, in a population subjected
to substantial reduction.
(2) The annual rate of increase was estimated to be r =
0.21. This estimate was compared with the exponential rate
of increase in another recovering donkey population and
found to be in close agreement.
(3) Ultimate and proximate factors regulating the
abundance of feral donkey populations were examined by
monitoring and sampling two populations; one at or close to
equilibrium density, the other below equilibrium density and
recovering from reduction.
(4) The size of the population at equilibrium density
remained stable over the 12 months of monitoring while the
size of the recovering population increased by 20 percent
(r = 0.18/yr).
(5) Growth and body condition were significantly
depressed in the population at equilibrium density
suggesting that donkey populations are limited by the food
resources available to them.
(6) Breeding occured over a discrete season, with
births occurring between September and February.
11
(7) Fecundity was high, with more than 75 percent of
mature females breeding in each year, and was independent of
population density.
(8) Adult and juvenile mortality were density
dependent, with mortality over the first six months of life
the most important demographic factor influencing rate of
increase in donkey populations, and hence population
abundance.
(9) Implications of the estimated rate of population
increase for the cost of long-term control of feral donkey
populations were examined by constructing numerical models
predicting the relative cost of ongoing control.
(10) These models were constructed using functions to
describe density dependent variation in population
productivity and the cost per donkey removed.
(11) The cost of removing donkeys at various population
densities was estimated using predator-prey theory. The
cost, measured in hours of helicopter time per removal, was
found theoretically and empirically to take the form of an
inverted functional response curve, with cost saturated at
high donkey densities.
(12) The utility of models predicting the cost of
continuing pest control is illustrated by comparing the
relative costs of two potential strategies for feral donkey
control.
34
Nekoie-Moghadam, Mahmoud. "Planning and management of population programmes in Islamic Republic of Iran : social factors influencing effective planning and cost-effectiveness considerations for management." Thesis, Keele University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321406.
Full text
35
Winder, Linton. "Modelling the effects of polyphagous predators on the population dynamics of the grain aphid Sitobion avenae (F.)." Thesis, University of Southampton, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.278694.
Full text
36
Wang, Duolao. "Contraceptive use dynamics in China." Thesis, University of Southampton, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.259492.
Full text
37
Canatto, Bianca Davico. "Caracterização das populações de cães e gatos domiciliadas no município de São Paulo." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/10/10134/tde-03022011-131309/.
Full textAbstract:
O presente trabalho teve como objetivo estimar as populações canina e felina domiciliadas nos distritos administrativos do município de São Paulo, caracterizando-as demograficamente, bem como o oferecimento de cuidados veterinários e a forma de manutenção dos animais em domicílio. Para tal, utilizou-se amostragem complexa com seleção aleatória em dois estágios: setores censitários e domicílios. Em cada distrito administrativo, foram visitados seis setores censitários e 20 domicílios em cada setor sorteado. De setembro de 2006 a setembro de 2009, um total de 11.272 entrevistas foram feitas. A média de cão/domicílio com cão foi estimada em 1,60 e a média de gato/domicílio com gato, 1,69. A razão homem:cão foi estimada em 4,34 e a razão homem:gato, 19,33. A partir da população humana de 10.882.121 habitantes, no ano de 2007, estimou-se a população animal em 2.507.401 cães e 562.965 gatos. A população canina é composta de 52,7% de machos, enquanto a felina, de 45,1%. A proporção de felinos castrados (39,0%) foi superior a dos caninos (17,1%), considerando ambos os gêneros. As proporções de fêmeas esterilizadas (23,4% dentre os cães e 46,1% dentre os gatos) são superiores às de machos (11,4% dentre os cães e 31,5% dentre os gatos), em ambas as espécies. A idade média de cães foi estimada em 4,99 anos e a de gatos, 3,53 anos. A proporção de gatos não vacinados contra a raiva nos últimos 12 meses (6,8%) foi superior à proporção de cães (1,6%). A proporção de cães com restrição de acesso à rua (64,4%) foi superior à dos gatos (42,5%). A restrição e a esterilização dos animais são reflexos da posse responsável que deve ser incessantemente discutida e divulgada a fim de promover conscientização dos proprietários quanto aos modos de manutenção e oferecimento de cuidados veterinários. A caracterização das populações animais é a base da estruturação de progamas de controle populacional e de zoonoses. Estudos populacionais que respeitam a heterogeinedade dos aspectos administrativos e geográficos de um município, permitem medidas de ações em saúde mais direcionadas.The present work aimed at estimate the owned dog and cat populations at the administrative districts of São Paulo city, in terms of its demography, but also the veterinary care and maintenance of animals. To achieve this goal, a complex sample with random selection in two stages (censitary sectors and households) was used. Six censitary sectors in each administrative district and 20 households in each sampled sector were visited. From September 2006 to September 2009, 11.272 interviews were made. The dog per household with dogs average was 1.60 and the cat per household with cats average was 1.69. The human:dog ratio was 4.34 and the human:cat ratio was 19.33. Since the human population was 10,882,121, in 2007, the dog population was estimated in 2,507,401 and the cat population in 562,965. The dog population was composted of 52.7% males, while among the cat population was 45.1%. The proportion of both male and female sterilized cats (39,0%) was higher than dogs (17.1%). The proportion of sterilized females (23.4% among dogs and 46.1% among cats) was higher than males (11.4% among dogs and 31.5% among cats) in both species. The mean age of dogs was 4.99 years as for cats, 3.53 years. The proportion of cats non-vaccinated against rabies (6.8%) was higher than dogs (1.6%) in the last 12 months. The proportion of restricted (access to the street) dogs (64.4%) was higher than restricted cats (42.5%). The animal restriction and sterilization are effects of responsible ownership and must be constantly discussed and disseminated to improve owners awareness about the way of maintaining and providing veterinary care to dogs and cats. The characterization of canine and feline populations is essential to structure an animal population management programme and zoonosis control. Population studies must respect the heterogeneity of administrative and geographical aspects of a municipality in order to provide more focused measures of public health.
38
Maas, Sylvana, and n/a. "Population dynamics and control of feral goats in a semi-arid environment." University of Canberra. Resource, Environmental & Heritage Sciences, 1997. http://erl.canberra.edu.au./public/adt-AUC20060825.132138.
Full textAbstract:
The ability of feral herbivores to reduce the amount of food available to domestic livestock has
rarely been quantified. This thesis seeks to examine the degree to which feral goats (Capra
hircus) reduce the availability of pasture and shrub biomass for other herbivores. The
interaction between feral goat populations and their food supply will be explored using a
modelling approach. In addition to this it will also examine the cost of controlling goats and
attempt to identify the cost efficient target densities for control operations. The implications of
this information for management will be discussed.
There are two ways an animal population can interact with its food supply, through: (1)
intrinsic food shortages, and (2) extrinsic food shortages. Intrinsic food shortages occur when a
negative feed-back loop exists between the animal population and their food supply. This
means the animals affect the availability of their food and their food supply affects the
dynamics of the animal population. Since the animals are affecting their own food supply it
could be said that they will also affect the availability of that food to other herbivores if they
consume the same species. Extrinsic food shortages occur when there is no feed-back from the
animals to their food supply. Food availability is determined by extrinsic factors such as
rainfall and is unaffected by the animal population. To determine how feral goats interact with
their food supply several models will be examined, and these include: (1) single species models
which use data from the animal population only. These have historically been used to identify
density dependence which is commonly caused by the animal population being regulated
through their food supply in the case of large herbivores, and (2) trophic models which
incorporate data from at least two trophic levels in an ecosystem, in this case those being the
animal population and the vegetation they are thought to consume. These models allow a more
direct examination of the relationship between the feral goat population and their food supply.
The various models were fitted to data collected on the field sites and the following results
were obtained:
(1) the dynamics of the feral goat populations could not be represented by single-species
models. This was most probably due to the stochastic environment in which they lived
causing the level of density dependence experienced by the goats to vary greatly masking its
presence.
(2) the rate of increase of the goat population could be predicted by the numerical response of
rate of increase to pasture biomass. This demonstrated that food availability influenced the
dynamics of the goat population.
(3) goat density affected the availability of some species of shrub biomass. There was,
however, no response seen in the availability of pasture species to changes in goat density.
Since the study was conducted during a drought this is in agreement with other studies
which indicated that goats will primarily browse during dry spells but switch to pasture
species when conditions improve following rainfall.
These results indicate that a negative feed-back loop does exist between feral goat populations
and their food supply since the goats affected the availability of some shrub species and so they
suffer intrinsic food shortages. This means goats have the ability to reduce the availability of
food to other herbivores providing both are eating the same species.
Cost-efficiency analysis showed that the cost of removing individual feral goats increases
exponentially as density decreases because the search time per animal becomes greater. This
relationship was used to construct a model that predicted the cost of achieving a target density.
The model describing cost of control over density was also combined with a productivity
model based on the numerical response of feral goats to pasture biomass to predict the cost of
maintaining target densities under different environmental conditions. Using these models the
most cost-efficient density identified was 11 goats/km2.
From this study we can make the following conclusions:
(1) feral goats have the ability to reduce the amount of shrub biomass available to other
herbivores during dry conditions
(2) their ability to influence the availability of pasture species remains unknown
(3) given the cost of initial and ongoing control and the minimal benefits that result it would be
difficult to justify controlling goats during a drought on the field sites.
39
Skeat, Andrew, and n/a. "Feral buffalo in Kakadu National Park : survey methods, population dynamics and control." University of Canberra. Applied Science, 1990. http://erl.canberra.edu.au./public/adt-AUC20061108.161608.
Full textAbstract:
(1) Aerial survey methods for estimating
population size of feral water buffalo in northern
Australia were examined.
(2) Line transect models underestimated population
size. Of six models tested the most accurate
underestimated by nearly half. The models give
biased estimates most probably because not all
animals on the survey line were sighted .
(3) Aerial strip transect surveys were also
negatively biased. The extent of this bias was
estimated in index-removal experiments.
Experiments were carried out on two populations in
areas of differing obstructive canopy cover.
(4) In woodland habitat with a canopy cover of 30-
60%, a correction factor of 3.2 was required to
take account of animals not seen. In forest
habitat with a canopy cover of 60-100%, a
correction factor of 4.9 was required.
(5) Using these results, the population size of
feral buffalo, cattle and horses in Kakadu National
Park was estimated by aerial survey at the end of
each year over 6 years. Annual rates of increase
for three regions of the Park were estimated,
taking into account known removals from the
population. The effects of dry season rainfall and
population density in the preceding year on rate of
increase were examined for each species.
(6) The mean annual exponential rate of increase
for each species was 0.10 yr-1 for buffalo, 0.23
yr-1 for cattle and -0.14 yr-1 for horses.
(7) The annual rates of increase varied greatly
between years within all species and were highly
correlated with dry season rainfall in the year of
survey for buffalo and cattle but not for horses.
(8) No significant effect of preceding density on
rate of increase was found for any species. A
large reduction in buffalo populations did not
correspond with an increase in unharvested
populations of horses, suggesting the two species
do not compete for food or other resources.
(9) A campaign to control populations of feral
water buffalo in Kakadu National Park was assessed.
Between 1979 and 1988, approximately 79,000 animals
were removed, 54% by commercial live-capture, 35%
by shooting from helicopters and 10% by shooting
from the ground.
(10) In the period 1983-1988 when population
estimates from aerial survey are available, mean
buffalo population density was reduced from
5.60 km-2 to 1.17 km-2 over the surveyed area of
the Park.
(11) The costs of removal by shooting from
helicopters, capturing animals alive and shooting
from the ground were compared. The mean costs per
animal in 1988 were $24.13, $74.53, and $86.02
respectively.
(12) The effects of initial density and time spent
shooting on number of animals removed by shooting
from helicopters were examined. One linear and two
curvilinear models were fitted to data from four
different removal exercises. The relationship
between time spent shooting and number removed was
best described by a curvilinear (Ivlev) function.
This model was used to estimate costs of control to
a specified density.
(13) Model regression coefficients differed
between removal exercises, suggesting that the
number removed may be affected by variables other
than time spent shooting and initial density. Data
from the range of conditions encountered during
removal is thus likely to be required for robust
estimation of removal costs.
40
Sun, Jingjing Ph D. Massachusetts Institute of Technology. "Towards synthetic ecology : genetically programmable 4-module population control system in yeast." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/90678.
Full textAbstract:
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Biological Engineering, 2014.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 155-165).
Communities of microorganisms are found nearly ubiquitously on earth. They survive and proliferate through interactions within and between microbial species, which are mediated by the exchange of small signaling modules. Understanding how they regulate the interactions is both crucial and challenging, with applications including industrial biotechnology, human health and environmental sustainability. In microbial ecology, researchers have been trying to culture pure and mixed species in different conditions to elucidate the rules behind the interactions. However, the studies have been complicated by multiple variables at both the genotype and phenotype levels. To address these challenges, I demonstrate a synthetic ecological system as a proof of principle to observe microbial population level behaviors. Using a formalized design process and engineering principles, I design and construct a synthetic multi-module ecological system for population homeostasis. The synthetic ecological system consists of four functionally distinct modules - quorum sensing, high threshold killing, low threshold killing, and intermediate rescuing modules. The system is able to maintain the yeast population within a programmable range in liquid culture. However, when the same system is studied in solid medium, heterogeneity in growth rate and population size is observed. To further study the heterogeneity issue in solid medium, I develop a cell deposition platform to evaluate sub-population level or even single-cell level behavior. With a commercial Nano eNabler machine, cells with pre-defined patterns are deposited on agarose surface. This technique can be used to study microbial communities in a spatially distributed fashion.
by Jingjing Sun.
Ph. D.
41
Chapman, Allison Claire. "The changing Phytophthora infestans population : implications for late blight epidemics and control." Thesis, University of Dundee, 2012. https://discovery.dundee.ac.uk/en/studentTheses/a651a487-9b3f-4bd8-956b-703dec57d514.
Full textAbstract:
Phytophthora infestans, the causal agent of potato late blight, causes millions of pounds of losses worldwide each year. Within the UK P. infestans populations there has been a dramatic increase in the proportion of the A2 mating type due to genotype 13_A2 and concerns have been raised about whether this population change affects the reliability of the UK late blight forecasting system. The Smith Period is commonly used in the UK to predict blight risk on the basis of two criteria; on two consecutive days the minimum temperature must be 10°C or above and the relative humidity must be 90% or above for 11 hours on each of the days. The objective of this thesis is to examine the aggressiveness, competitiveness and response of contemporary UK genotypes to temperature and humidity. This was to understand more about what has driven the success of the 13_A2 lineage and how the population changes may have affected the validity of blight predictions based on the Smith Period. The laboratory studies did not provide conclusive evidence to explain the UK dominance of genotype 13_A2 as there were few consistent differences in aggressiveness or environmental response observed between genotypes. However, 13_A2 outcompeted other genotypes in the field trial showing that aggressiveness is best determined over multiple life cycles. The biological parameters tested showed that infection was seen at 6°C for 10 of the 11 contemporary UK genotypes tested. In whole plant tests, some infection was recorded after as little as 2 hours exposure to high humidity and after 6 hours exposure more than 10% foliar blight was seen. The Smith Period criteria thus need to be revaluated using up to date biological parameters of contemporary P. infestans populations to provide accurate prediction of potato late blight risk for growers.
42
Stich, Daniel Stephen. "Behavior and population dynamics of grass carp incrementally stocked for biological control." Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/34212.
Full textAbstract:
Grass carp Ctenopharyngodon idella have been stocked throughout the world due to their utility as a biological control. In the United States, the species has been used to successfully control invasive, aquatic weeds such as hydrilla Hydrilla verticillata. Despite the large body of research surrounding the use of grass carp, few studies have demonstrated widely applicable methods for evaluating the success of weed control based on grass carp behavior and population dynamics. Classic methods of biological control using grass carp often rely on a single, large stocking of fish. Few of these studies have demonstrated success in achieving intermediate levels of weed control. Managers would be better equipped to make decisions regarding stocking and maintenance grass carp populations with better information about behavior, survival, and population structure. Improved decision making could result in reduced cost and increased effectiveness of stocking. In order to examine current knowledge gaps for management, I investigated the movements and habitat use of grass carp, post-stocking survival, age-specific survival rates, and population dynamics of grass carp in Lake Gaston, North Carolina and Virginia.
I characterized relationships between grass carp behavior and environmental factors using radio-telemetry. The average rate of movement for grass carp in Lake Gaston was about 137 m/d. Rapid dispersal after stocking was followed by long periods of no movement. However, when time after stocking was held constant in models of behavior, fish moved about 200 m/d more in the second year after stocking than in the first year, and were found closer to shore. On average, grass carp were found about 40 m from shore in about 2.5-3.5 m of water, although mean depth of water at grass carp locations varied seasonally, being shallowest in summer and deepest in winter. Although depth of water at grass carp locations did not vary by stocking location, Grass carp were found closer to shorelines in the upper reservoir than in the lower reservoir. I found significant relationships between grass carp behavior and hydrological processes such as lake elevation and dam releases in the reservoir, as well as with other environmental factors such as water temperature, photoperiod, and weather conditions. The results of this study should be useful in better understanding how behavior can affect management decisions. Specifically, grass carp behavior appears to change with age and environmental conditions within large reservoir systems. Future research should focus more closely on the effects of large-scale flow dynamics on grass carp behavior.
I estimated age-1 survival of grass carp from mark-recapture models designed for radio-tagged animals, and characterized relationships between age-1 survival and factors under the control of management, such as stocking locations and size at stocking. . According to the most-plausible model developed in this study, survival of age-1 grass carp in Lake Gaston varied throughout the year, and the probability of an individual grass carp surviving to the end of its first year (±SE) was 0.57(±0.10). According to the second-most-plausible model developed in this study, grass carp survival varied between stocking locations, and was twice as high in the upper reservoir (0.87±0.09) than in the lower reservoir (0.43±0.11). The differences in survival between stocking locations suggest that the cost-effectiveness of grass carp stocking could be improved by focusing stocking efforts in specific regions of Lake Gaston. Furthermore, none of the models developed in this study that incorporated the effects of size (length and weight) or condition factor accounted for a meaningful amount of the total model weights. These results suggest that costs of grass carp stocking could be reduced in Lake Gaston by using a smaller minimum size (352 mm, TL) than is commonly referred to in the literature (450 mm, TL).
I used grass carp collected by bowfishers in Lake Gaston to characterize the age, growth, and survival of grass carp in the system. From these data, I characterized relationships between fish population dynamics and annual hydrilla coverage. Grass carp collected from Lake Gaston ranged in age 1-16 years. Growth of grass carp in Gaston was described by the von Bertalanffy growth function as Lt = 1297(1-e -0.1352 (t+1.52)). I estimated mortality from the von Bertalanffy growth parameters using methods based on growth, temperature, and age; and with each mortality estimate I estimated population size and standing biomass of grass carp. Use of age-specific mortality rates produced lower estimates of grass carp numbers and standing biomass in Lake Gaston than did the use of a single, instantaneous mortality rate for all ages. I determined that growth of grass carp slowed considerably after the fourth year and that slowed growth, in combination with changes in mortality, resulted in a decrease in the amount of hydrilla controlled by a given cohort after four years in Lake Gaston. This phenomenon resulted in an approximately linear relationship between the biomass of grass carp at year i and hectares of hydrilla at year i+3. Based on this relationship, I predicted that the biomass of grass carp necessary to reduce hydrilla coverage to the target level of 120 ha in Lake Gaston is about 91,184 kg (±38,146 kg) and that the current biomass of grass carp in Lake Gaston is about 108,073 kg (±3,609 kg). I conclude that grass carp biomass is at or near levels that should reduce hydrilla coverage to 120 ha between 2013 and 2018. This research provides an effective means for synthesis of information that is critical to understanding sterile, triploid grass carp populations when assumptions of other methods cannot be met. The results of this study should be of immediate utility to hydrilla management efforts in Lake Gaston and other systems. Furthermore, the age-specific mortality rates developed in this study should be useful as starting values for grass carp management in similar systems.Master of Science
43
Teel, William Baldwin. "A population-based case-control study risk factors for connective tissue diseases /." Thesis, Connect to this title online; UW restricted, 1997. http://hdl.handle.net/1773/10893.
Full text
44
Milwertz, Cecilia Nathansen. "Accepting population control : urban Chinese women and the one-child family policy /." Richmond : Curzon, 1997. http://catalogue.bnf.fr/ark:/12148/cb37023631d.
Full text
45
Klosinski, Vance J. "Population and resource control measures a conceptual framework for understanding and implementation." Thesis, Monterey, California : Naval Postgraduate School, 2009. http://edocs.nps.edu/npspubs/scholarly/theses/2009/Dec/09Dec%5FKlosinski.pdf.
Full textAbstract:
Thesis (M.S. in Defense Analysis)--Naval Postgraduate School, December 2009.Thesis Advisor(s): Simmons, Anna. Second Reader: Lee, Doowan. "December 2009." Description based on title screen as viewed on January 27, 2010. Author(s) subject terms: Population and resource control measures, Population control, Counterinsurgency, COIN, Populationcentric COIN, Social control, Social movement theory. Includes bibliographical references (p. 51-53). Also available in print.
46
Greer, Beverley Jean. "Personality type, spirituality, and locus-of-control in an older adult population." Diss., The University of Arizona, 1992. http://hdl.handle.net/10150/186036.
Full textAbstract:
The purpose of this dissertation was to examine the relationships among spirituality, personality preferences, and locus of control. Subjects, aged 50 and over, completed four self-report instruments in small group sessions. The instruments included a biographical information questionnaire, an abbreviated version of Rotter's Internal Versus External Control of Reinforcement Scale, the Spiritual Perspective Scale, and the Myers-Briggs Type Indicator Form G (shortened version). Data were collected in one-hour sessions. One hundred sixty-one Caucasian men and women from varied socioeconomic levels were involved in the study. Initial data analysis indicated that there was only one significant relationship among the sociodemographic variables and the main study variables. Subjects rated their financial situation using a 4-item scale ranging from just enough money to enough money and substantial savings. Reported higher income level correlated with internal locus of control. An analysis of locus of control scores and spirituality scores using a t-test for mean differences indicated that there was no significant difference between the mean scores of men and of women on either instrument. The mean locus of control scores and the mean spirituality scores of subjects aged 50-64 and those of subjects aged 65-83 likewise did not differ significantly. To analyze the relationships between personality preferences and locus of control, or personality preferences and spirituality, a one-way analysis of variance using least significant difference for multiple comparisons for all the groups was used. Results indicated that one study combination of personality preferences, NT (intuition with thinking), had significantly lower (more internal) locus of control scores than two of the other groupings, ST (sensing with thinking) and SF (sensing with feeling). Results from analyses of the spirituality scores indicated that all groupings containing the feeling (F) dimension had significantly higher scores on spirituality than the other groupings. Comparison of locus of control and spirituality scores showed no relationship. An analysis of the relationships of physical variables, personality variables, and social variables to internal locus of control revealed that only the function group of NT (intuition with thinking) showed a slight, but significant, relationship to internal locus of control.
47
Scott, Penelope Anne. "The efficacy of a mass media population control campaign in Jamaica's national development." Thesis, University of Leicester, 1992. http://hdl.handle.net/2381/34612.
Full textAbstract:
In 1983 the Jamaican Parliament officially endorsed a National Population Policy which made the island the first in the Caribbean region to formulate such a policy. The Population Policy defined Jamaica's accelerating population as a negative constraint on the country's national development. One of the aims therefore, of the Policy was the introduction of replacement fertility i.e. a two child family. This was stipulated as a prerequisite to limit Jamaica's population growth. In an effort to disseminate the message of the two child family three mass media campaigns were conducted in the nineteen eighties. This thesis examines the efficacy of this replacement fertility campaign strategy in Jamaica's national development. The campaign's efficacy will be examined on the basis of its conceptualisation and implementation. This thesis constructs the argument that firstly, the conceptualisation of the media campaign was based on academically discredited views and assumptions on the role of the media in development. This position is substantiated in two ways. Firstly, through a semiotic analysis of the advertising campaign which revealed the implicit level of expectations concerning the campaign as well as the media's role in development. Secondly, through interviews with campaign planners and policy makers which disclosed the explicit expectations regarding the media and the campaign's function in development. It is argued that the ideological nature of the campaign's mythic structure, deciphered through the semiotic analysis, implies a role for the media in development which is consistent with the views of communication scholars who were advocates of the currently discredited Modernisation based model of communication in national development. An analysis of interviews with the campaign planners and policymakers demonstrates that their expressed views on the role of the media in development are identifiable with assumptions on this role inherent in the Modernisation paradigm. The thesis argues secondly, that the misinformed criteria and expectations directing the campaign are further reinforced by several features of the campaign design and implementation. It is shown that certain principles and practices of campaign design such as audience research, pretesting and interpersonal communication, which are academically proven ingredients of successful campaigns, were neglected in the campaign's construction. This calls into question the integrity of the campaign as a mechanism of social intervention. Further challenges to the campaign's efficacy are raised by findings from a social survey among the target group. This survey sought to assess the audience's view on the two child family; patterns of mass media use; sources of information on family planning; the credibility of these sources compared with the credibility of the media; contraceptive use and information needs on contraception.
48
Medina, Carlos. ""The Very Insides of Nationality": Reproduction, Reform, and Birth Control as Population Control in 20th Century Puerto Rico." OpenSIUC, 2020. https://opensiuc.lib.siu.edu/dissertations/1853.
Full textAbstract:
This dissertation examines the long term effects of population control initiatives brought to the U.S. commonwealth of Puerto Rico to reveal the connections between insular reform programs and the constraints placed on reproductive autonomy for Puerto Rican women in a colonial setting. The history of these interventions exposes how various interest groups including mainland reformers, the Catholic Church, Puerto Rican nationalists and socialists, and colonial intermediaries obscured the damage done to Puerto Rico through poor colonial management during the first thirty years of U.S. occupation by shifting the blame for Puerto Rico’s problems to the supposedly dangerous reproductive habits of poor and working class Puerto Rican women. In all cases, overpopulation discourse and the production of knowledge claims regarding Puerto Rican sexuality, reproduction, population control as a tool of modernization contributed heavily to these pressure groups’ appeals to legitimacy of rule over the island throughout the century. In less than fifty years the conflation of birth control practices, eugenic ideology, and population control legislation would transform Puerto Rico into a social science/contraceptive laboratory, having such a profound impact on the trajectory of birth control culture that a 1981 fertility survey showed that over one third (39%) of the island’s women were sterile. By analyzing the production of this distorted representation of insular conditions and reproduction trends in Puerto Rico during this early phase of U.S. control over the island, this dissertation explores how the convergence of modernizing reform initiatives, population control policy, social science, and overpopulation discourse contributed to the colonial domination of Puerto Rican women’s reproductive autonomy and transformed their into sites of colonial encounters despite living in a nation which denies its own colonial status and history.
49
Liu, Huolong. "Modeling and control of batch pulsed top-spray fluidized bed granulation." Thesis, De Montfort University, 2014. http://hdl.handle.net/2086/11006.
Full textAbstract:
In this thesis, a thorough study of the batch top-spray fluidized bed granulation was carried out including experimental study, population balance model (PBM), computational fluid dynamic (CFD) study and control strategy development. For the experimental study, the influence variables of pulsed frequency, binder spray rate and atomization pressure of a batch top-spray fluidized bed granulation process were studied using the Box-Behnken experimental design method. Different mathematical models were developed to predict the mean size of granules, yield, relative width of granule distribution, Hausner ratio and final granule moisture content. Validation experiments have shown the reliability and effectiveness of using the Box-Behnken experimental design method to study a fluidized bed granulation process. The one-dimensional population balance models (ODPBMs) have been developed to model a pulsed top-spray fluidized bed granulation, linking the operating factors of the pulsed frequency, the binder spray rate, and atomization air pressure with the granule properties to predict granule growth behavior at different operating conditions. A multi-stage open optimal control strategy based on the developed ODPBMs was proposed to reduce the model and process mismatch through adjusting the trajectory of the evolution of the granule size distribution at predefined sample intervals. The effectiveness of the proposed modeling and multi-stage open optimal control strategy has been validated by experimental and simulation tests. In addition, an Eulerian-Eulerian two-fluid model (EETFM) was developed to describe the gas-particle two-phase flow in the fluidized bed granulator. By computational fluid dynamic analysis, it has been proven that the fluidized bed granulation system is not homogeneous, based on which a two-compartmental population balance model (TCPBM) was developed to describe the particle growth in the fluidized bed granulation. Validation experiments have shown the effectiveness and superior accuracy of the TCPBM comparing with the ODPBM in predicting the final particle size distribution.
50
Bill, Adam. "Nonnegative feedback systems in population ecology." Thesis, University of Bath, 2016. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.698987.
Full textAbstract:
We develop and adapt absolute stability results for nonnegative Lur'e systems, that is, systems made up of linear part and a nonlinear feedback in which the state remains nonnegative for all time. This is done in both continuous and discrete time with an aim of applying these results to population modeling. Further to this, we consider forced nonnegative Lur'e systems, that is, Lur'e systems with an additional disturbance, and provide results on input-to-state stability (ISS), again in both continuous and discrete time. We provide necessary and sufficient conditions for a forced Lur'e system to have the converging-input converging-state (CICS) property in a general setting before specializing these results to nonnegative, single-input, single-output systems. Finally we apply integral control to nonnegative systems in order to control the output of the system with the key focus being on applications to population management.