Birth Pulse Research Articles

Who is afraid of modelling time as a continuous variable?

Abstract Most models of ecological and eco‐evolutionary processes involve creating trajectories of something, be it population densities, average trait values, or environmental states, over time. This requires decision‐making regarding how to represent the flow of time in models. Most ecologists are exposed to continuous‐time models (typically in the form of ordinary differential equations) as part of their training, especially since the famous Lotka‐Volterra predator–prey dynamics are formulated this way. However, few appear sufficiently well trained to produce their own work with continuous‐time models and may lack exposure to the true versatility of available methods. Specifically, knowledge that discrete individuals can be modelled in continuous time using the Gillespie algorithm is not as widespread as it should be. I will illustrate the flexibility of continous‐time modelling methods such that researchers can make informed choices, and not resort to discretizing time as a ‘default’ without a clear biological motivation to do so. I provide three example‐based tutorials: (1) a comparison of deterministic and stochastic dynamics of the Lotka‐Volterra predator–prey model, (2) an evaluation of matelessness in a hypothetical insect population (and of selection to mate more often by either searching more efficiently or by shortening the ‘time out’ after each mating) and (3) within‐season density dependence followed by a birth pulse leading to Beverton‐Holt or Ricker dynamics depending on whether the deaths of conspecifics help reduce the mortality of others or not (compensatory mortality). I highlight properties of the exponential distribution that, while counter‐intuitive, are good to know when deriving expected lifetime reproductive success or other similar quantities. I also give guidance on how to proceed if the so‐called memorylessness assumption does not hold in a given situation, and show how continuous and discrete times can be freely mixed if the biological situation dictates this to be the preferred option. Continuous‐time models can also be empirically fitted to data, and I review briefly the insight this gives into the so‐called ‘do hares eat lynx?’ paradox that has been plaguing the interpretation of the Hudson Bay hare and lynx dataset.

A Comparative Study of Coagulation Profiles in Preeclamptic and Normotensive Patients in Relation to Maternal and Fetal Outcomes.

Background Hypertensive complications during pregnancy play a significant role in the increased rates of maternal and perinatal morbidity and mortality on a global scale. Preeclampsia is characterized by elevated blood pressure levels and the presence of protein in the urine and is associated with diverse hematological alterations, particularly impacting the coagulation cascade. The primary objective of this research was to conduct a comparative analysis of the coagulation profiles and pregnancy outcomes in women with preeclampsia versus those with normal blood pressure during pregnancy. Methods This was a prospective case-control study with 74 participants across two groups, conducted from September 2022 to May 2024. The participants were enrolled and divided into two groups, with 37 in the clinically diagnosed preeclampsia group and 37 in the normotensive group. Coagulation parameters including platelet count, bleeding time, clotting time, international normalized ratio (INR), activated partial thromboplastin time (APTT), prothrombin time (PT), fibrinogen levels, alkaline phosphatase (ALP) levels, D-dimer levels, and fibrin degradation products (FDP) levels were assessed. Maternal and neonatal outcomes were also compared. In our study, we comprehensively examined both maternal and neonatal outcomes in preeclampsia and normotensive groups. Maternal complications analyzed included mode of delivery, incidence of eclampsia, placental abruption, hemolysis, elevated liver enzymes, and low platelets (HELLP) syndrome, postpartum hemorrhage (PPH), and peripartum cardiomyopathy (PPCM). For neonatal outcomes, we assessed birth weight, appearance, pulse, grimace, activity, and respiration (APGAR) scores, and the duration of neonatal intensive care unit (NICU) stays. Results The results showed that mean platelet count was significantly lower in the preeclampsia group (151,503 ± 59,875/µL) compared to the normotensive group (245,405 ± 69,021/µL) (p < 0.0001). Bleeding time, INR, APTT, and PT showed significant elevation in the preeclampsia group, indicating a slower coagulation process. Fibrinogen levels, ALP levels, and D-dimer levels were significantly higher in the preeclampsia group (p < 0.0001). The preeclampsia group had a higher rate of cesarean sections (65% vs. 24%) and lower neonatal birth weights (mean 2.3 kg vs. 2.5 kg). APGAR scores were comparable between groups, but a higher number of neonates went to the NICU in the preeclampsia group (64.9% vs. 10.8%). The preeclampsia group also showed higher rates of low birth weight (27%), intrauterine growth restriction (27%), respiratory distress syndrome (10.8%), and asphyxia (5.4%). Conclusion Preeclampsia is associated with significant hematological changes, particularly in coagulation parameters, and adverse fetomaternal outcomes. Early identification and monitoring of these changes are crucial for timely intervention and improving maternal and neonatal health outcomes.

Optimal Timing of Cesarean Section Following Two or More Prior Cesareans: An Investigation Into Maternal and Neonatal Outcomes (a Two-Center Study).

Objective This study aimed to determine the optimal timing of elective cesarean sections for women with two or more prior cesarean deliveries by investigating maternal and neonatal outcomes across different gestational ages (37weeks, 38 weeks, and 39 weeks). Methods A retrospective cohort study was conducted at Tawam and Kanad Hospitals in Al Ain, United Arab Emirates, including 435 women with previous cesarean deliveries. Data were collected on patient demographics, obstetric history, maternal complications, and neonatal outcomes, such as birth weight, appearance, pulse, grimace, activity, and respiration (APGAR) scores, neonatal intensive care unit (NICU) admissions, and length of NICU stay. The patients were divided into two groups: those with two prior cesareans and those with three or more. Outcomes were analyzed based on gestational age at delivery. Results Elective cesarean sections constituted 81.0% of the procedures, with no significant difference in the distribution of elective versus emergency cesareans across the studied gestational weeks (P = 0.073). Neonatal outcomes indicated healthy birth weights and low NICU admissions. For women with two prior cesareans, the NICU admission rates were 23.53% for deliveries at 37weeks, 8.11% at 38 weeks, and 4.35% for deliveries beyond 39 weeks. For women with three or more prior cesareans, NICU admission rates were 18.18% for 37weeks, 20.00% for 38weeks, and 10.00% for 39 weeks. The average birth weight increased with gestational age, and NICU stays were longer for earlier deliveries (P = 0.0065 for stays > 5 days). Conclusion The findings suggest that the optimal timing for elective cesarean sections in women with two or more prior cesareans is 39 weeks of gestation. This timingis associated with the best neonatal outcomes, including lower NICU admission rates and healthy birth weights while minimizing the risks associated with earlier deliveries. Scheduling elective cesarean sections at 39 weeks will improve maternal and neonatal health benefits.

Dynamics of a predator–prey fishery model with birth pulse, impulsive releasing and harvesting on prey

Dynamics of a predator–prey fishery model with birth pulse, impulsive releasing and harvesting on prey

A Bayesian analysis of birth pulse effects on the probability of detecting Ebola virus in fruit bats

A Bayesian analysis of birth pulse effects on the probability of detecting Ebola virus in fruit bats

Season, prey availability, sex, and age explain prey size selection in a large solitary carnivore.

Prey selection is a fundamental aspect of ecology that drives evolution and community structure, yet the impact of intraspecific variation on the selection for prey size remains largely unaccounted for in ecological theory. Here, we explored puma (Puma concolor) prey selection across six study sites in North and South America. Our results highlighted the strong influence of season and prey availability on puma prey selection, and the smaller influence of puma age. Pumas in all sites selected smaller prey in warmer seasons following the ungulate birth pulse. Our top models included interaction terms between sex and age, suggesting that males more than females select larger prey as they age, which may reflect experiential learning. When accounting for variable sampling across pumas in our six sites, male and female pumas killed prey of equivalent size, even though males are larger than females, challenging assumptions about this species. Nevertheless, pumas in different study sites selected prey of different sizes, emphasizing that the optimal prey size for pumas is likely context-dependent and affected by prey availability. The mean prey weight across all sites averaged 1.18 times mean puma weight, which was less than predicted as the optimal prey size by energetics and ecological theory (optimal prey = 1.45 puma weight). Our results help refine our understanding of optimal prey for pumas and other solitary carnivores, as well as corroborate recent research emphasizing that carnivore prey selection is impacted not just by energetics but by the effects of diverse ecology.

Kenyan Free-Tailed Bats Demonstrate Seasonal Birth Pulse Asynchrony with Implications for Virus Maintenance

Ecological information on wildlife reservoirs is fundamental for research targeting prevention of zoonotic infectious disease, yet basic information is lacking for many species in global hotspots of disease emergence. We provide the first estimates of synchronicity, magnitude, and timing of seasonal birthing in Mops condylurus, a putative ebolavirus host, and a co-roosting species, Mops pumilus (formerly Chaerephon pumilus). We show that population-level synchronicity of M. condylurus birthing is wide (~ 8.5 weeks) and even wider in M. pumilus (> 11 weeks). This is predicted to promote the likelihood of filovirus persistence under conditions of bi-annual birthing (two births per year). Ecological features underlying the magnitude of the birth pulse—relative female abundance (higher than expected for M. condylurus and lower for M. pumilus, based on literature) and reproductive rate (lower than expected)—will have countering effects on birthing magnitude. Species-specific models are needed to interpret how identified birth pulse attributes may interact with other features of molossid ebolavirus ecology to influence infection dynamics. As a common feature of wildlife species, and a key driver of infection dynamics, detailed information on seasonal birthing will be fundamental for future research on these species and will be informative for bat-borne zoonoses generally.

A study to evaluate the burden of hearing loss and its correlation with risk factors among high-risk infants at a teaching institution, Jaipur.

Hearing loss is a global issue of hearing disability and early detection and rehabilitation of hearing loss are important for the development of speech and language skills in hearing-impaired infants. There are multiple risk factors that aid in hearing loss but some are potential factors that contribute toward hearing loss in infants. The aim of this study was to assess the burden of hearing loss and its correlation with risk factors among high-risk infants at a teaching institution in Jaipur, Rajasthan. This study was carried out after approval of institutional ethics committee on a total of 320 high-risk infants at RUHS College of medical sciences and associated hospitals. Hearing loss was assessed by brainstem evoked response audiometry (BERA). Statistical analysis of data was done by cross-tabulation analysis with Pearson correlation and quantile regression. Out of 320 high-risk infants, 59.69% of infants had normal hearing, 9.09% Unilaterally hearing impaired, 20.31% were bilaterally mild-moderate hearing loss, and 10.94% had severe-profound deafness. The prevalence of important risk factors viz. hyperbilirubinemia, low birth weight, appearance, pulse, grimace, activity, and respiration score, meconium aspiration, respiratory distress, and ventilation greater than five days were 86%, 58.9%, 40%, 36%, 29%, and 22%, respectively. In high-risk infants, hearing loss is a common hearing disorder. Because of this, early diagnosis of hearing loss gives them the best chance of developing functional speech. Brainstem evoked response audiometry is a simple, reliable, and effective technique for the assessment of auditory functions in infants.

An Observational Study on Impact of COVID-19 in Pregnancy: Clinical Profiles and Foetomaternal Outcomes in Caesarean Section Cases at a Tertiary Care Centre, Gujarat, India

Introduction: The Coronavirus Disease 2019 (COVID-19) pandemic, caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection, has resulted in a crippled healthcare system worldwide. In this unprecedented situation, it is important to analyse the impact on the vulnerable population of pregnant women, especially those with high-risk pregnancies and those undergoing a Caesarean section (CS). Aim: To analyse the clinical profile, foetomaternal outcomes, and co-morbidities in COVID-19-affected pregnancy cases undergoing a CS. Materials and Methods: This was a retrospective observational study conducted at the Department of Obstetrics and Gynaecology, Government Medical College, and New Civil Hospital in Surat, Gujarat, India during the first wave of the COVID-19 pandemic from April 2020 to December 2020. The study included a total of 65 cases of COVID-19-positive mothers undergoing a C-section. Demographic parameters such as age, obstetric history, details of the C-section (like gestational age at the time of the procedure, indication, and category of the C-section), associated co-morbidities, severity of COVID-19- related symptoms and treatment, neonatal parameters {such as birth weight, Appearance, Pulse, Grimace, Activity and Respiration (APGAR) score, and COVID-19 status of the baby at birth} were analysed. Additionally, a comparison of the C-section rate and complications such as the development of severe anaemia requiring blood transfusion, postoperative development of urinary tract infections, surgical site infections, and the association of hypertensive disorders of pregnancy was conducted between COVID-19-affected and unaffected pregnancies undergoing a C-section during the study period. Data on COVID-19 negative cases were obtained from the monthly labour room statistics submitted to the department. The Chi-square test and Fisher’sexact test were used to compare parameters of the COVID-19 positive and negative groups and a p-value of less than 0.05 was considered statistically significant. Results: Out of a total of 6246 deliveries conducted at the institute during the study period, the CS rate among affected and non affected women was 44.5% (65 out of 146) vs. 32.8% (2006 out of 6100) {p=0.003, Relative Risk (RR) 1.3, 95% Confidence Interval (CI) 1.12-1.62}. The mean age of women with COVID19 undergoing a CS was 25.3 years. The difference in the rate of blood transfusion requirement in COVID-19-affected cases was 9 out of 65 (13.8%) vs. 120 out of 2006 (6%) in COVID-19 negative pregnancies (RR 2.3, 95% CI: 1.2-4.3). The difference in the rate of urinary tract infections in the postoperative period was statistically significant in COVID-19-infected patients, 5 out of 65 (7.7%) vs. 58 out of 2006 (2.9%) in non infected patients (p=0.0451, RR 2.6, 95% CI 1.1-6.4). The prevalence of hypertensive disorders among COVID-19 positive and negative mothers undergoing CS was very high in the present study (16 out of 65, 24.6% vs. 160 out of 2006, 8.1%, RR 3.08, 95% CI 1.9-4.8). Neonatal parameters like low APGAR score at birth were seen in 5 cases (8%), low birth weight in 20 cases (30%), and 3 babies (4.5%) were COVID-19 positive at birth. Conclusion: Higher rates of caesarean sections, increased prevalence of hypertensive disorders of pregnancy, anaemia requiring blood transfusion, and postoperative development of urinary tract infections among COVID-19-affected mothers undergoing a caesarean section.

Spreading dynamics of an impulsive reaction-diffusion model with shifting environments

This paper focuses on the effects of environmental improvement and worsening on the spread and invasion of populations with birth pulse. We propose an impulsive reaction-diffusion model with a shifting environment to describe the dynamics of species with distinct reproduction stage and dispersal stage. First, the impulsive reaction-diffusion model is reduced to a discrete-time recursive system defined by a discrete map. Next, with the aid of the appropriate test function and comparison principle, we obtain some sufficient conditions on the nonexistence and uniqueness of nontrivial fixed points of the discrete map. This, combined with the abstract theory of spatially non-translation dynamical systems, enables us to establish the existence of traveling wave solutions and the asymptotic propagation properties of the model.

Dynamical Behaviors in a Stage-Structured Model with a Birth Pulse

This paper presents an exploitation model with a stage structure to analyze the dynamics of a fish population, where periodic birth pulse and pulse fishing occur at different fixed time. By utilizing the stroboscopic map, we can obtain an accurate cycle of the system and investigate the stability thresholds. Through the application of the center manifold theorem and bifurcation theory, our research has shown that the given model exhibits transcritical and flip bifurcation near its interior equilibrium point. The bifurcation diagrams, maximum Lyapunov exponents and phase portraits are presented to further substantiate the complexity. Finally, we present high-resolution stability diagrams that demonstrate the global structure of mode-locking oscillations. We also describe how these oscillations are interconnected and how their complexity unfolds as control parameters vary. The two parametric planes illustrate that the structure of Arnold’s tongues is based on the Stern–Brocot tree. This implies that the periodic occurrence of birth pulse and pulse fishing contributes to the development of more complex dynamical behaviors within the fish population.

Coursing the mottled mosaic: Generalist predators track pulses in availability of neonatal ungulates.

The density and distribution of resources shape animal movement and behavior and have direct implications for population dynamics. Resource availability often is "pulsed" in space and time, and individuals should cue in on resource pulses when the energetic gain of doing so exceeds that of stable resources. Birth pulses of prey represent a profitable but ephemeral resource and should thereby result in shifting functional responses by predators. We evaluated movements and resource selection of coyotes (Canis latrans) across a gradient of reproductive stages ranging from late gestation to peak lactation of female mule deer (Odocoileus hemionus) in southwest Wyoming, USA, to test whether coyotes exhibited shifts in selection and movement behavior relative to the availability and vulnerability of neonatal mule deer. We expected coyotes to track pulses in availability of neonatal mule deer, and such behavior would be represented by shifts in resource selection and search behavior of coyotes that would be strongest during peak parturition of mule deer. Coyotes selected areas of high relative probability of use by female mule deer and did so most strongly during peak parturition. Furthermore, searching behavior of coyotes intensified during pulses of availability of deer neonates. Our findings support the notion that coyotes exploit pulses of neonatal deer, presumably as an attempt to capitalize on a vulnerable, energy-rich resource. Our work quantifies the behavioral mechanisms by which coyotes consume ungulate neonates and provides one of the first examples of a mammalian predator-prey system centered on a pulsed resource.

Perioperative Outcome of COVID-19-Positive Parturient Posted for Cesarean Section—Our Experience in a Tertiary Care Hospital in Northern India

Introduction There is insufficient data regarding the severity of coronavirus disease 2019 (COVID-19) infections in pregnant women. This study assessed the outcome of COVID-19-positive parturient after cesarean section, correlation of maternal mortality with COVID-19 severity, association of comorbid parturients with severe COVID-19, and number of patients requiring general anesthesia. Materials and Methods This single-center, retrospective observational study was performed on reverse transcriptase polymerase chain reaction confirmed COVID-19-positive 89 parturients posted for elective or emergency cesarean section. Data was collected from medical records of our hospital regarding COVID-19 severity, maternal mortality, need for admission in intensive care unit, gestational age, maternal comorbidities, indication for cesarean section, type of anesthesia, duration of surgery, neonatal birth weight, neonatal mortality, Appearance, Pulse, Grimace, Activity and Respiration (APGAR) score, and neonatal intensive care unit (NICU) admission. Assessment of maternal outcome was the primary objective. Secondary objectives of this study were to correlate maternal outcome with COVID-19 severity, to find association of comorbid parturients with severe COVID-19 and to estimate number of patients requiring general anesthesia. Results Out of 89 patients, 79 patients had mild COVID-19 disease were on room air and 6 patients required preoperative oxygen supplementation, and 4 patients diagnosed to have severe COVID-19 pneumonia were on mechanical ventilator preoperatively. Four cases were operated under general anesthesia and remaining 85 parturients were operated under regional anesthesia. Out of four parturients with severe COVID-19 pneumonia, three patients did not survive in postoperative period due to refractory hypoxemia. In eight patients, spinal anesthesia was repeated due to inadequate effect. Fourteen neonates (16.09%) required NICU stay after cesarean delivery. Conclusions Parturients with severe COVID-19 disease had higher mortality. No statistically significant association was found between number of comorbidities and severity of COVID-19. The results of this study will guide us regarding further management and prognostication of COVID-19-positive parturients posted for cesarean section.

A seasonal pulse of ungulate neonates influences space use by carnivores in a multi-predator, multi-prey system.

The behavioral mechanisms by which predators encounter prey are poorly resolved. In particular, the extent to which predators engage in active search for prey versus incidentally encountering them has not been well studied in many systems and particularly not for neonate prey during the birth pulse. Parturition of many large herbivores occurs during a short and predictable temporal window in which young are highly vulnerable to predation. Our study aims to determine how a suite of carnivores responds to the seasonal pulse of newborn ungulates using contemporaneous global positioning system (GPS) locations of four species of predators and two species of prey. We used step‐selection functions to assess whether coyotes, cougars, black bears, and bobcats encountered parturient adult female ungulates more often than expected by chance in a low‐density population of mule deer and a high‐density population of elk. We then assessed whether the carnivore species that encountered parturient prey more often than expected by chance did so by shifting their habitat use toward areas with a high probability of encountering neonates. None of the four carnivore species encountered GPS‐collared parturient mule deer more often than expected by chance. By contrast, we determined that cougar and male bear movements positioned them in the proximity of GPS‐collared parturient elk more often than expected by chance which may provide evidence of searching behavior. Although both male bears and cougars exhibited behavior consistent with active search for neonates, only male bears used elk parturition habitat in a way that dynamically tracked the phenology of the elk birth pulse suggesting that maximizing encounters with juvenile elk was a motivation when selecting resources. Our results suggest that there is high interspecific and intersexual variability in foraging strategies among large mammalian predators and their prey.

Reproduction, seasonal morphology, and juvenile growth in three Malagasy fruit bats.

The island nation of Madagascar is home to three endemic species of Old World fruit bat in the family Pteropodidae: Pteropus rufus, Eidolon dupreanum, and Rousettus madagascariensis, all three of which are IUCN Red Listed under some category of threat. Delineation of seasonal limits in the reproductive calendar for threatened mammals can inform conservation efforts by clarifying parameters used in population viability models, as well as elucidate understanding of the mechanisms underpinning pathogen persistence in host populations. Here, we define the seasonal limits of a staggered annual birth pulse across the three species of endemic Madagascar fruit bat, known reservoirs for viruses of high zoonotic potential. Our field studies indicate that this annual birth pulse takes place in September/October for P. rufus, November for E. dupreanum, and December for R. madagascariensis in central-eastern Madagascar where the bulk of our research was concentrated. Juvenile development periods vary across the three Malagasy pteropodids, resulting in near-synchronous weaning of pups for all species in late January-February at the height of the fruiting season for this region. We here document the size range in morphological traits for the three Malagasy fruit bat species, with P. rufus and E. dupreanum among the larger of pteropodids globally and R. madagascariensis among the smaller. All three species demonstrate subtle sexual dimorphism with males being larger than females. We explore seasonal variation in adult body condition by comparing observed body mass with body mass predicted by forearm length, demonstrating that pregnant females add weight during staggered gestation periods and males lose weight during the nutritionally deficit Malagasy winter. Finally, we quantify forearm, tibia, and ear length growth rates in juvenile bats, demonstrating both faster growth and more protracted development times for P. rufus as compared with E. dupreanum and R. madagascariensis. The longer development period for the already-threatened P. rufus further undermines the conservation status of this species as human hunting is particularly detrimental to population viability during reproductive periods. Our work highlights the importance of longitudinal field studies in collecting critical data for mammalian conservation efforts and human public health alike.

Fetomaternal outcome in patients with threatened abortion in the first trimester – An observational study

Background: Uterine bleeding in early pregnancy represents a definite threat to developing embryo and is directly proportional to the amount of bleeding. It is associated with an increased risk of poor obstetric and neonatal outcomes such as preterm labor, low birth weight, and premature rupture of membranes (PROM). Aims and Objectives: This study aims to investigate the effect of the first trimester vaginal bleeding on maternal and perinatal outcomes. Materials and Methods: This prospective observational study carried out in a tertiary teaching hospital of Kolkata, between January 2019 and June 2020. Here,190 patients with the first trimester vaginal bleeding were included in the study. Outcome of pregnancy was assessed in the form of obstetrical complications such as placenta previa, PROM, preterm labor, intrauterine fetal death, intrauterine growth retardation (IUGR), and neonatal outcomes such as prematurity, low birth weight, low appearance, pulse, grimace, activity, and respiration, requirement of newborn intensive care unit (NICU) admission, and perinatal death. Results: Our study shows that 116 (61.05%) out of 190 were primi gravida and rest 74 (38.95%) were multigravida. Seventy-five (39.47%) had missed abortion, 43 (22.63%) patients had incomplete abortion, and 23(12.10%) out of 190 patients resulted in complete abortion. About 19.47% (37 out of 190) had viable pregnancy. Six(16.21%)out of 37patients had preterm delivery, 4(10.81%)out of 37 patients had antepartum hemorrhage. Preeclampsia developed in 8.1% (three out of 37) patients. About 48.64% (18) delivered vaginally, 45.94% (17) underwent lower segment cesarean section, and only 2(5.40%) patients had instrumental delivery(forceps). Regarding neonatal outcome, 5.40% had early neonatal death, 21.62% needed NICU admission, 8.10% suffered from fetal distress, 5.40% had meconium stained liquor, 8.10% were IUGR, and 32.43%had birth weight &lt;1.5 kg. Conclusion: The first trimester bleeding is a predicting factor for obstetric and perinatal complications during pregnancy.

PERSISTENCE, EXTINCTION AND BLOWUP IN A GENERALIZED LOGISTIC MODEL WITH IMPULSES AND REGIONAL EVOLUTION

<abstract> To explore the impacts of regional evolution and impulses on the persistence or extinction of species, a generalized logistic model with impulses in an evolving domain is proposed and researched. Firstly, the ecological reproduction index, which is regarded as a threshold value, is introduced and characterized. Secondly, in the case of monotone or non-monotone impulsive function, the asymptotic behavior of population is fully investigated and the sufficient conditions for the solution to persist, be extinct or blow up are given. Finally, numerical simulations results indicate that whatever impulse is, larger periodic evolution rates are more favorable for species. However, impulsive harvesting has a negative impact on persistence of species, while birth pulse admits a positive impact and even results in blowup. </abstract>

Multigravida Women With Moderate to Severe Anaemia in Third Trimester: Fetomaternal Outcomes.

Background & Objectives: Anaemia has been reported to be associated with adverse pregnancy outcomes, especially when presenting in the last trimester. In addition to prevalent common causes of anaemia in pregnant women, poor replenishment of iron stores after a pregnancy event is specific to women with higher birth orders. Anaemic women presenting in the third trimester are more prone to maternal complications such as infections, toxaemia, antepartum haemorrhage, cardiac failure, pre-eclampsia as well as fetal hazards too such as low birth weight, pre-term deliveries, developmental anomalies, and even neonatal death. When presented near term there are higher chances of feto-maternal morbidity and mortality. In the current study, analysis is done of feto-maternal outcomes, routes of delivery of women, causes of anaemia in multigravida women in the third trimester suffering from moderate to severe anaemia in a tertiary care centre of Western Rajasthan of India.Methods: A prospective observational clinical study was conducted on patients attending Geetanjali Hospital over a period of 18 months. A total of 70 consecutive multigravida pregnant women having moderate to severe anaemia in the third trimester were selected. Statistical analysis of the data collected was done and a p-value <0.05 was taken as significant.Results: Moderate and severe anaemia in the study population were 44.28% and 55.71%, respectively. The mean haemoglobin level of all study groups was 7.0 gm%. Pre-eclampsia, placenta praevia, postpartum haemorrhage (PPH), congestive cardiac failure (CHF), neonatal intensive care unit (NICU) admission, preterm birth (PTB), low birth weight (LBW), intrauterine death (IUD), low Appearance, Pulse, Grimace, Activity, and Respiration (APGAR) score, and birth asphyxia records were investigated. Of the patients studied, 18.57% had PPH, 15.71% had pre-eclampsia, 8.57% had IUD, and 37.14% newborns were LBW.Interpretations and Conclusion: Multiparity itself is a major risk factor of anemia. Anemia presenting in the third trimester of pregnancy is a proxy indicator of care received by gravid women in the early antenatal period. In combination, a multigravida in the third trimester with less time to restock iron and vitamin stores may result in considerable maternal as well as perinatal mortality and morbidity.

Oral Sylvatic Plague Vaccine Does Not Adequately Protect Prairie Dogs (Cynomys spp.) for Endangered Black-Footed Ferret (Mustela nigripes) Conservation.

The plague bacterium Yersinia pestis is lethal to endangered black-footed ferrets (Mustela nigripes, BFF) and the prairie dogs (Cynomys spp., PD) on which they depend for habitat and prey. We assessed the effectiveness of an oral sylvatic plague vaccine delivered in baits to black-tailed PD (Cynomys ludovicianus, BTPD) from 2013 to 2017 on the Charles M. Russell National Wildlife Refuge (CMR) in northcentral Montana. We permanently marked BTPD on four paired vaccine (N = 1,349 individuals) and placebo plots (N = 926; 7,027 total captures). We analyzed capture–recapture data under a Cormack–Jolly–Seber model to estimate annual apparent survival. Overall, survival averaged 0.05 lower on vaccine plots than on paired placebo plots. Immediately before noticeable die-offs and detecting plague on pairs CMR1 and CMR2, 89% of BTPD sampled on vaccine plots had consumed at least one bait and the immune systems of 40% were likely boosted by consuming baits over multiple years. Survival to the following year was 0.16 and 0.05 on the vaccine plots and 0.19 and 0.06 on the placebo plots for pairs CMR1 and CMR2, respectively. These rates were markedly lower than 0.63, the overall average estimate on those same plots during the previous 3 years. PD populations subjected to such large die-offs would not be expected to sustain a BFF population. An overriding limitation to achieving sufficient protection rests with vaccine delivery constraints. Late summer/fall bait distribution results in the highest bait uptake rates. However, the PD birth pulse each spring can double the size of populations in most years, greatly reducing the proportion of vaccinates in populations and diminishing potential herd immunity benefits. In addition to nonvaccinated juveniles and PD that do not consume bait, incomplete vaccine protection and time required for immunity to develop leaves a large majority of PD populations vulnerable to plague for 6–7 months or more each year.

Effects of Waning Maternal Immunity on Infection Dynamics in Seasonally Breeding Wildlife.

Increasing outbreaks of emerging infectious diseases originating from wildlife have intensified interests in understanding their dynamics in reservoir hosts. The effect of waning maternally derived antibodies on epidemics in a seasonally breeding wild mammal population is unclear. We examined how the population structure, influenced by seasonal breeding and maternally derived immunity, affects viral invasion and persistence using a hypothetical system based on Hendra virus infection in black flying foxes (Pteropus alecto). A deterministic Hendra virus epidemic model with uncertainty in parameter values was used to simulate transient epidemics following viral introduction into an infection-free population, including various timings within a year and differences in pre-existing seroprevalence. Additionally, we applied different modelling methods of waning maternal immunity to examine whether different models notably affected modelling outputs. The waning of maternally derived immunity temporally dispersed the supply of susceptible individuals in seasonally breeding populations, diminishing the effect of birth pulses generating the temporally synchronised supply of susceptible newborns. Thus, even in a population with seasonal births, a considerable level of probabilities of viral invasion and persistence could occur no matter when infectious individuals were introduced into the population. Viral invasion and persistence were substantially influenced by the modelling method of maternally derived immunity, emphasising the need to select an appropriate method and further investigate the waning pattern of maternally derived antibodies.