Assessment of anthropogenic-causing-agents act on waterbirds-diversity in the vicinity of Tarbela Dam, Indus River, Pakistan

Abstract Birds are among the best bio-indicators, which can guide us to recognize some of the main conservation concerns in ecosystems. Anthropogenic impacts such as deforestation, habitat degradation, modification of landscapes, and decreased quality of habitats are major threats to bird diversity. The present study was designed to detect anthropogenic causative agents that act on waterbird diversity in Tarbella Dam, Indus River, Pakistan. Waterbird censuses were carried out from March 2019 to February 2020 in multiple areas around the dam. A total of 2990 waterbirds representing 63 species were recorded. We detected the highest waterbird richness and diversity at Pehure whereas the highest density was recorded at Kabbal. Human activity impacts seemed to be the main factor determining the waterbird communities as waterbirds were negatively correlated with the greatest anthropogenic impacts. Waterbirds seem to respond rapidly to human disturbance.

Resumo As aves estão entre os melhores bioindicadores, o que pode nos orientar a reconhecer algumas das principais preocupações de conservação dos ecossistemas. Impactos antrópicos como desmatamento, degradação de habitat, modificação de paisagens e diminuição da qualidade dos habitats são as principais ameaças à diversidade de aves. O presente estudo foi desenhado para detectar agentes causadores antropogênicos que atuam na diversidade de aves aquáticas na Represa de Tarbella, rio Indus, Paquistão. Censos de aves aquáticas foram realizados de março de 2019 a fevereiro de 2020 em várias áreas ao redor da barragem. Um total de 2.990 aves aquáticas representando 63 espécies foi registrado. Detectamos a maior riqueza e diversidade de aves aquáticas em Pehure, enquanto a maior densidade foi registrada em Kabbal. Os impactos da atividade humana parecem ser o principal fator determinante das comunidades de aves aquáticas, uma vez que as aves aquáticas foram negativamente correlacionadas com os maiores impactos antrópicos. As aves aquáticas parecem responder rapidamente às perturbações humanas.

Assessment of anthropogenic-causing-agents act on waterbirds-diversity in the vicinity of Tarbela Dam, Indus River, Pakistan / Avaliação de agentes antropogênicos que agem na diversidade de aves aquáticas nas proximidades da Represa de Tarbela, rio Indus, Paquistão

Abstract Birds are among the best bio-indicators, which can guide us to recognize some of the main conservation concerns in ecosystems. Anthropogenic impacts such as deforestation, habitat degradation, modification of landscapes, and decreased quality of habitats are major threats to bird diversity. The present study was designed to detect anthropogenic causative agents that act on waterbird diversity in Tarbella Dam, Indus River, Pakistan. Waterbird censuses were carried out from March 2019 to February 2020 in multiple areas around the dam. A total of 2990 waterbirds representing 63 species were recorded. We detected the highest waterbird richness and diversity at Pehure whereas the highest density was recorded at Kabbal. Human activity impacts seemed to be the main factor determining the waterbird communities as waterbirds were negatively correlated with the greatest anthropogenic impacts. Waterbirds seem to respond rapidly to human disturbance.

Resumo As aves estão entre os melhores bioindicadores, o que pode nos orientar a reconhecer algumas das principais preocupações de conservação dos ecossistemas. Impactos antrópicos como desmatamento, degradação de habitat, modificação de paisagens e diminuição da qualidade dos habitats são as principais ameaças à diversidade de aves. O presente estudo foi desenhado para detectar agentes causadores antropogênicos que atuam na diversidade de aves aquáticas na Represa de Tarbella, rio Indus, Paquistão. Censos de aves aquáticas foram realizados de março de 2019 a fevereiro de 2020 em várias áreas ao redor da barragem. Um total de 2.990 aves aquáticas representando 63 espécies foi registrado. Detectamos a maior riqueza e diversidade de aves aquáticas em Pehure, enquanto a maior densidade foi registrada em Kabbal. Os impactos da atividade humana parecem ser o principal fator determinante das comunidades de aves aquáticas, uma vez que as aves aquáticas foram negativamente correlacionadas com os maiores impactos antrópicos. As aves aquáticas parecem responder rapidamente às perturbações humanas.

Seasonal Changes in Hematological Parameters in House Sparrows of Subtropical Pakistan.

House sparrow is a globally adaptive bird. The way this creature adapted to all areas of the world, having different selection pressures, is interesting to understand. The present study is focused on seasonal changes, having different selection pressures and how it is adapted to these changes and whether hematological flexibility plays a role in this success. House sparrow's adaptations in the same area, during different seasons, have been studied in a sub-tropical area, Potohar, Pakistan. We used hematological parameter analysis for this purpose. Blood samples were collected from Sparrows in winter, spring, and summer and analyzed for some hematological parameters. White blood cells (WBCs) were higher in spring and summer which may relate to mating promiscuity. Sparrows were more stressed in summer. The Red blood cells (RBCs) and hematocrit (Hct) were greater in summer. Mean corpuscular volume (MCV) is lower in summer. This may have an adaptation to cope with high stress in summer as small-size RBCs increase gaseous exchange. Platelets were not affected by season or gender. Mean corpuscular volume and Mean corpuscular hemoglobin (MCH) are positively correlated with each other. Red blood cells, hemoglobin (Hb) and MCV were higher in males during the spring season perhaps as an adaptation to energetic activities during spring like mating calls and search for nesting sites. White blood cells remained the same in both genders in summer and winter, and effected in spring may be related to the mating system. Behavioral state is linked with physiological states that shows tradeoff and life history traits. This study is a small effort to know this incredible species. We can work further in different parts of the world to explore different aspects of it.

El gorrión común es un ave que se adapta globalmente. La forma en que esta criatura se adaptó a todas las áreas del mundo, teniendo diferentes presiones de selección, es interesante de entender. El presente estudio se centra en los cambios estacionales, teniendo diferentes presiones de selección y cómo se adapta a estos cambios y si la flexibilidad hematológica juega un papel en este éxito. Las adaptaciones de House Sparrow en la misma área, durante diferentes estaciones, se han estudiado en un área subtropical, Potohar, Pakistán. Utilizamos el análisis de parámetros hematológicos para este propósito. Se recogieron muestras de sangre de gorriones en invierno, primavera y verano y se analizaron algunos parámetros hematológicos. Los glóbulos blancos (WBC) fueron más altos en primavera y verano, lo que puede relacionarse con la promiscuidad de apareamiento. Los gorriones estaban más estresados ​​en verano. Los glóbulos rojos (GR) y el hematocrito (Het) fueron mayores en verano. El volumen corpuscular medio (MCV) es menor en verano. Esto puede tener una adaptación para hacer frente al alto estrés en verano, ya que los glóbulos rojos de pequeño tamaño aumentan el intercambio gaseoso. Las plaquetas no se vieron afectadas por la estación o el género. El MCV y la hemoglobina corpuscular media (MCH) se correlacionan positivamente entre sí. Los glóbulos rojos, la hemoglobina (Hb) y el MCV fueron más altos en los machos durante la temporada de primavera, tal vez como una adaptación a las actividades energéticas durante la primavera, como llamadas de apareamiento y búsqueda de sitios de anidación. Los glóbulos blancos se mantuvieron iguales en ambos sexos en verano e invierno, y los efectuados en primavera pueden estar relacionados con el sistema de apareamiento. El estado de comportamiento está relacionado con estados fisiológicos que muestran rasgos de compensación y de historia de vida. Este estudio es un pequeño esfuerzo por conocer esta increíble especie. Podemos trabajar más en diferentes partes del mundo para explorar diferentes aspectos del mismo.

Le Moineau domestique est un oiseau qui s"adapte à l"échelle mondiale. La façon dont cette créature s"est adaptée à toutes les régions du monde, ayant des pressions de sélection différentes, est intéressante à comprendre. La présente étude se concentre sur les changements saisonniers, ayant différentes pressions de sélection et comment il est adapté à ces changements et si la flexibilité hématologique joue un rôle dans ce succès. Les adaptations du Moineau domestique dans la même zone, à différentes saisons, ont été étudiées dans une zone subtropicale, Potohar, Pakistan. Nous avons utilisé l"analyse des paramètres hématologiques à cette fin. Des échantillons de sang ont été prélevés sur des moineaux en hiver, au printemps et en été et analysés pour certains paramètres hématologiques. Les globules blancs (WBC) étaient plus élevés au printemps et en été, ce qui peut être lié à la promiscuité sexuelle. Les moineaux étaient plus stressés en été. Les globules rouges (GR) et l"hématocrite (Het) étaient plus élevés en été. Le volume corpusculaire moyen (MCV) est plus faible en été. Cela peut avoir une adaptation pour faire face à un stress élevé en été, car les globules rouges de petite taille augmentent les échanges gazeux. Les plaquettes n"étaient pas affectées par la saison ou le sexe. Le MCV et l"hémoglobine corpusculaire moyenne (MCH) sont positivement corrélés l"un à l"autre. Les globules rouges, l"hémoglobine (Hb) et le MCV étaient plus élevés chez les mâles au printemps, peut-être en raison d"une adaptation aux activités énergétiques au printemps comme les cris d"accouplement et la recherche de sites de nidification. Les globules blancs sont restés les mêmes chez les deux sexes en été et en hiver, et effectués au printemps peuvent être liés au système d"accouplement. L"état comportemental est lié aux états physiologiques qui montrent des traits de compromis et d'histoire de vie. Cette étude est un petit effort pour connaître cette espèce incroyable. Nous pouvons continuer à travailler dans différentes parties du monde pour en explorer différents aspects.

Protease production and molecular characterization of a protease dipeptidyl-aminopeptidase gene from different strains of Sordaria fimicola.

The current research was designed to reach extracellular protease production potential in different strains of Sordaria fimicola which were previously obtained from Dr. Lamb (Imperial College, London) from North Facing Slope and South Facing Slope of Evolution Canyon. After initial and secondary screening, two hyper-producers strains S2 and N6 were selected for submerged fermentation and cultural conditions including temperature, pH, incubation period, inoculum size, substrate concentration, and different carbon and nitrogen sources were optimized for enzyme production. S2 strain showed maximum protease production of 3.291 U/mL after 14 days of incubation at 30 °C with 7 pH, 1% substrate concentration and 1 mL inoculum, While N6 strain showed maximum protease production of 1.929 U/mL under fermentation optimized conditions. Another aim of the present research was to underpin the biodiversity of genetics and post-translational modifications (PTMs) of protease DPAP (peptidyl-aminopeptidase) in Sordaria fimicola. Five polymorphic sites were observed in amino acid sequence of S. fimicola strains with reference to Neurospora crassa. PTMs prediction from bioinformatics tools predicted 38 phosphorylation sites on serine residues for protease peptidyl-aminopeptidase in S1 strain of S. fimicola while 45 phosphorylation sites on serine in N7 strain and 47 serine phosphorylation modifications were predicted in N. crassa. Current research gave an insight that change in genetic makeup effected PTMs which ultimately affected the production of protease enzyme in different strains of same organism (S. fimicola). The production and molecular data of the research revealed that environmental stress has strong effects on the specific genes through mutations which may cause genetic diversity. S. fimicola is non- pathogenic fungus and has a short life cycle. This fungus can be chosen to produce protease enzyme on a commercial scale.

Assessment of anthropogenic-causing-agents act on waterbirds-diversity in the vicinity of Tarbela Dam, Indus River, Pakistan.

Birds are among the best bio-indicators, which can guide us to recognize some of the main conservation concerns in ecosystems. Anthropogenic impacts such as deforestation, habitat degradation, modification of landscapes, and decreased quality of habitats are major threats to bird diversity. The present study was designed to detect anthropogenic causative agents that act on waterbird diversity in Tarbella Dam, Indus River, Pakistan. Waterbird censuses were carried out from March 2019 to February 2020 in multiple areas around the dam. A total of 2990 waterbirds representing 63 species were recorded. We detected the highest waterbird richness and diversity at Pehure whereas the highest density was recorded at Kabbal. Human activity impacts seemed to be the main factor determining the waterbird communities as waterbirds were negatively correlated with the greatest anthropogenic impacts. Waterbirds seem to respond rapidly to human disturbance.

Radiative Double-Electron Capture by Bare and One-Electron Ions on Gas Targets.

Radiative double-electron capture (RDEC) involves the transfer of two electrons with the simultaneous emission of a single photon. This process, which can be viewed as the inverse of double photoionzation, has been studied for 2.11 MeV/u F^{9+} and F^{8+} ions striking gas targets of N_{2} and Ne. The existence of RDEC is conclusively shown for both targets and the results are compared with earlier O^{8+} and F^{9+} findings for thin-foil carbon and with theory. The data for the carbon target showed some evidence for the existence of RDEC, but the interpretation was clouded by high-probability, unavoidable multiple collisions causing the exiting charge state to be increased.

Association of the MTHFR C677T (rs1801133) polymorphism with idiopathic male infertility in a local Pakistani population.

The present study determined an association between idiopathic sperm disorders in a local Pakistani infertile male population and the MTHFR C677T polymorphism. After ruling out non genetic factors, a total of 437 idiopathic infertile men including 57 azoospermic, 66 oligospermic, 44 asthenozoospermic, 29 teratozoospermic, 20 oligoasthenospermic and 221 infertile normospermic men were recruited. Furthermore, 218 normospermic fertile men, who had two children (or more) were included as controls. The polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique was used to determine MTHFR C677T (rs1801133) polymorphism. A significant association of the minor MTHFR 677T allele with male infertility was observed (p <0.05). In addition, men with MTHFR 677 CT and TT genotypes were at a greater risk [odds ratio (OR): 1.81, 95% confidence interval (95% CI): 1.17-2.80, p = 0.008 and OR: 9.24, 95% CI: 1.20-70.92, p = 0.032, respectively] of infertility. All the subgroups of male infertility (azoospermic, oligospermic, asthenospermic, oligoasthenoteratospermic (OAT) and normospermic infertile) had significantly (p <0.05) higher frequencies of CT and TT genotypes when compared to fertile men. The combined genotypes (CT + TT) were also found significantly (OR: 2.01, 95% CI: 1.31-3.08, p <0.001) associated with male infertility. The results suggest that the polymorphism might be a factor of male infertility in the Pakistani population.

Domestic violence and consanguineous marriages - perspective from Rawalpindi, Pakistan.

Domestic violence is globally endemic and adversely impacts the health and economic well-being of women and society. This study used the standardized and validated assessment instrument "Woman Abuse Screening Tool" to study the prevalence of various forms of domestic violence among married women. The relationship between domestic violence and consanguineous marriage was studied using the chi-squared test. Cumulatively, 1010 married women were interviewed. Emotional abuse was the most commonly reported abuse, reported by 721 (71.4%) women as either often or sometimes, followed by sexual abuse and physical abuse, reported by 527 (52.2%) and 511 (50.6%) respectively. Being married to one's cousin did not protect married women from being abused either emotionally or physically by their husbands; thsi was statistically significant. There is a need for better understanding of the magnitude and scale of domestic violence in Pakistan by using standardized assessment tools for meaningful comparisons across different parts of the country over time.

Band gap engineering of zinc selenide thin films through alloying with cadmium telluride.

This work investigates band gap engineering of zinc selenide (ZnSe) thin films. This was achieved by mixing ZnSe with cadmium telluride (CdTe). The mass ratio (x) of CdTe in the starting material was varied in the range x = 0-0.333. The films were prepared using thermal evaporation. The chemical composition of the films was investigated through energy dispersive spectroscopy and Rutherford backscattering spectrometry. Structural analysis was carried out using X-ray diffraction and atomic force microscopy. Normal incidence transmittance and reflectance were measured over the wavelength range 300-1300 nm. The absorption coefficients and band gaps were determined from these spectrophotometric measurements. The band gap monotonically decreased from 2.58 eV (for x = 0) to 1.75 eV (for x = 0.333). Photocurrent measurements indicated that the maximum current density was obtained for films with x = 0.286. A figure of merit, based on crystallinity, band gap, and photocurrent, was defined. The optimum characteristics were obtained for the films with x = 0.231, for which the band gap was 2.14 eV.

PGC-1α transcriptional response and mitochondrial adaptation to acute exercise is maintained in skeletal muscle of sedentary elderly males.

The aim of the present study was to examine the effects of ageing and training status on (1) markers of skeletal muscle mitochondrial content and (2) the ability to activate the acute signalling pathways associated with regulating exercise-induced mitochondrial biogenesis. Muscle biopsies were obtained from the vastus lateralis muscle of young untrained (24 ± 4 years, n = 6; YU), young trained (22 ± 3 years, n = 6; YT), old untrained (65 ± 6 years, n = 6; OU) and old trained (64 ± 3 years, n = 6; OT) healthy males before and after (3 h and 3 days post-exercise) completion of high-intensity interval cycling exercise. In resting muscle, lifelong training preserved mtDNA, PGC-1α and COXIV protein content such that muscles from OT individuals were comparable to muscles from both YU and YT individuals, whereas lifelong sedentary behaviour reduced such markers of mitochondrial content. Regardless of age or training status, acute exercise induced comparable increases in p38MAPK phosphorylation immediately post-exercise, PGC-1α and COXIV mRNA expression at 3 h post-exercise and COXIV protein at 3 days post-exercise. Data demonstrate that lifelong endurance training preserves skeletal muscle PGC-1α content and that despite the mitochondrial dysfunction typically observed with sedentary ageing, muscles from sedentary elderly individuals retain the capacity to activate the acute signalling pathways associated with regulating the early processes of mitochondrial biogenesis. We consider our data to have immediate translational potential as they highlight the potential therapeutic effects of exercise to induce skeletal muscle mitochondrial biogenesis persist late in adulthood, even after a lifetime of physical inactivity.

Fatalism and its implications for risky road use and receptiveness to safety messages: a qualitative investigation in Pakistan.

Given the increasing vehicle numbers and expanding road construction in developing countries, the importance of safe road user behaviour is critical. Road traffic crashes (RTCs) are a significant problem in Pakistan; however, the factors that contribute to RTCs in Pakistan are not well researched. Fatalistic beliefs are a potential barrier to the enhancement of road safety, especially participation in health-promoting and injury prevention behaviours, and also contribute to risk taking. Fatalistic beliefs relating to road safety have been found in some developing countries, although research is scarce and indicates that the nature and extent of fatalism differs in each country. Qualitative research was undertaken with a range of drivers, religious orators, police and policy makers to explore associations between fatalism, risky road use and associated issues. Findings indicate that fatalistic beliefs are pervasive in Pakistan, are strongly linked with religion, present a likely barrier to road safety messages and contribute to risky road use. Fatalism appears to be a default attribution of RTC and the intensity of belief in fate surpasses the kinds of fatalism noted in the limited existing literature. These findings have importance to developing road safety countermeasures in countries where fatalistic beliefs are strong.

Effect of xanthine oxidase-generated extracellular superoxide on skeletal muscle force generation.

Skeletal muscle contractions increase superoxide anion in skeletal muscle extracellular space. We tested the hypotheses that 1) after an isometric contraction protocol, xanthine oxidase (XO) activity is a source of superoxide anion in the extracellular space of skeletal muscle and 2) the increase in XO-derived extracellular superoxide anion during contractions affects skeletal muscle contractile function. Superoxide anion was monitored in the extracellular space of mouse gastrocnemius muscles by following the reduction of cytochrome c in muscle microdialysates. A 15-min protocol of nondamaging isometric contractions increased the reduction of cytochrome c in microdialysates, indicating an increase in superoxide anion. Mice treated with the XO inhibitor oxypurinol showed a smaller increase in superoxide anions in muscle microdialysates following contractions than in microdialysates from muscles of vehicle-treated mice. Intact extensor digitorum longus (EDL) and soleus muscles from mice were also incubated in vitro with oxypurinol or polyethylene glycol-tagged Cu,Zn-SOD. Oxypurinol decreased the maximum tetanic force produced by EDL and soleus muscles, and polyethylene glycol-tagged Cu,Zn-SOD decreased the maximum force production by the EDL muscles. Neither agent influenced the rate of decline in force production when EDL or soleus muscles were repeatedly electrically stimulated using a 5-min fatiguing protocol (stimulation at 40 Hz for 0.1 s every 5 s). Thus these studies indicate that XO activity contributes to the increased superoxide anion detected within the extracellular space of skeletal muscles during nondamaging contractile activity and that XO-derived superoxide anion or derivatives of this radical have a positive effect on muscle force generation during isometric contractions of mouse skeletal muscles.

Elevated core and muscle temperature to levels comparable to exercise do not increase heat shock protein content of skeletal muscle of physically active men.

AIM: Exercise-associated hyperthermia is routinely cited as the signal responsible for inducing an increased production of heat shock proteins (HSPs) following exercise. This hypothesis, however, has not been tested in human skeletal muscle. The aim of the present study was to therefore investigate the role of increased muscle and core temperature in contributing to the exercise-induced production of the major HSP families in human skeletal muscle. METHODS: Seven physically active males underwent a passive heating protocol of 1 h duration during which the temperature of the core and vastus lateralis muscle were increased to similar levels to those typically occurring during moderately demanding aerobic exercise protocols. One limb was immersed in a tank containing water maintained at approximately 45 degrees C whilst the contra-lateral limb remained outside the tank and was not exposed to heat stress. Muscle biopsies were obtained from the vastus lateralis of both legs immediately prior to and at 48 h and 7 days post-heating. RESULTS: The heating protocol induced significant increases (P < 0.05) in rectal (1.5 +/- 0.2 degrees C) and muscle temperature of the heated leg (3.6 +/- 0.5 degrees C). Muscle temperature of the non-heated limb showed no significant change (P > 0.05) following heating (pre: 36.1 +/- 0.5, post: 35.7 +/- 0.2 degrees C). Heating failed to induce a significant increase (P > 0.05) in muscle content of HSP70, HSC70, HSP60, HSP27, alphaB-crystallin, MnSOD protein content or in the activity of superoxide dismutase and catalase. CONCLUSIONS: These data demonstrate that increases in both systemic and local muscle temperature per se do not appear to mediate the exercise-induced production of HSPs in human skeletal muscle and suggest that non-heat stress factors associated with contractile activity are of more importance in mediating this response.

Desaturation and interconversion of dietary stearic and palmitic acids in human plasma and lipoproteins.

Dietary saturated fatty acids are implicated as a risk factor for atherosclerosis. The conversion of the major dietary saturated fatty acids stearic acid (18:0) and palmitic acid (16:0) to monounsaturated fatty acids in whole plasma and lipoprotein fractions is reported for seven healthy adult humans over 6 d using [U-13C]stearic acid (18:0*) and [U-13C]palmitic acid (16:0*) and high-precision mass spectrometry. A tracer dose (28-32 mg) of 18:0* or 16:0* was loaded into an emulsion and orally administered before breakfast. Serial blood samples were collected on day 1 and fasting blood was drawn daily until day 7. Overall conversion of 18:0 to 18:1 was approximately 14%, whereas that of 18:0 to 16:0 was approximately 2% in plasma up to 144 h. Conversion of 16:0 to 16:1 was < 2%, whereas conversion of 16:0 to 18:0 was approximately 6%. No other fatty acid metabolites were detected for 18:0* or 16:0*. The conversion products were observed mainly in chylomicrons and very-low-density lipoproteins, indicating that the intestine and liver have comparable roles in desaturating 18:0 and 16:0. Overall, these data indicate that dietary 18:0 desaturation is severalfold greater than 16:0 desaturation. The low level (14%) of 18:0 desaturation in omnivorous adults may have little influence on blood lipid profiles relevant to atherosclerosis risk.

Marriage delays in Pakistan: analysis of selected view points.

The authors explore reasons for the observed increases in marriage age in Pakistan. "Using anecdotal data from urban Pakistan, an attempt is made in this paper to analyse the perceived reasons that cause delay in marriage as well as some suggestions made by the respondents of this study to overcome the delay if necessary. In [pursuing] this objective, regional and gender variations with regard to reasons and suggestions are discussed."

Evaluation of international population projections: lessons and experiences.

Global and regional population projections produced by the United Nations are evaluated and compared with actual population estimates. While general observations pertaining to the global level are made, the focus is on Latin America for selected years from 1950 to 1980. It is found that "the quality of population projections improved since 1950. In addition, short-term projections are found to be relatively more accurate than those for the long-term.... In the medium- or long-term projections, at least in the Latin American case, the assumptions regarding mortality were far from the real situation. The important factors in the projections are found to be in the order of base population, fertility and mortality."

Stabilization process of human population: a descriptive approach.

PIP: An attempt is made to inquire into the process of stabilization of a human population. The same age distribution distorted by past variations in fertility is subjected to several fixed schedules of fertility. The schedules are different from each other monotonically over a narrow range. The primary concern is with the process, almost year by year, through which the populations become stable. There is particular interest in the differential impact in the same original age distribution of the narrowly different fixed fertility schedules. The exercise is prepared in 3 stages: general background of the process of stabilization; methodology and data used; and analysis and discussion of the stabilization process. Among the several approaches through which the analysis of stable population is possible, 2 are popular: the integral equation and the projection matrix. In this presentation the interest is in evaluating the effects of fertility on the stabilization process of a population. Therefore, only 1 initial age distribution and only 1 life table but a variety of narrowly different schedules of fertility have been used. Specifically, the U.S. 1963 female population is treated as the initial population. The process of stabilization is viewed in the light of the changes in the slopes between 2 successive age groups of an age distribution. A high fertility schedule with the given initial age distribution and mortality level overcomes the oscillations more quickly than the low fertility schedule. Simulation confirms the intuitively expected positive relationship between the mean of the slope and the level of fertility. The variance of the slope distribution is an indicator of the aging of the distribution.^ieng

[Comparison between the U.N. population projections for Latin America and actual estimates, 1950-1980]. / Comparacion entre proyecciones de poblacion elaboradas por las Naciones Unidas para la America Latina y estimaciones actuales, 1950-1980

"The purpose of this paper is to compare population projections prepared by the United Nations in the 1950's with the actual estimates for the countries and the regions of Central (including Mexico) and South America. The comparison is made in terms of (a) base population used in the projections (1950), (b) the projected and the estimated population for 1980, and (c) the projected and the estimated rates (including rates of growth) and numbers of births, deaths and migration over the 30 year period of the projections (1950-1980)." (SUMMARY IN ENG)