Hasil untuk "Reproduction"

B. Tang, N. Bragazzi, Qian Li et al.

The basic reproduction number of an infectious agent is the average number of infections one case can generate over the course of the infectious period, in a naïve, uninfected population. It is well-known that the estimation of this number may vary due to several methodological issues, including different assumptions and choice of parameters, utilized models, used datasets and estimation period. With the spreading of the novel coronavirus (2019-nCoV) infection, the reproduction number has been found to vary, reflecting the dynamics of transmission of the coronavirus outbreak as well as the case reporting rate. Due to significant variations in the control strategies, which have been changing over time, and thanks to the introduction of detection technologies that have been rapidly improved, enabling to shorten the time from infection/symptoms onset to diagnosis, leading to faster confirmation of the new coronavirus cases, our previous estimations on the transmission risk of the 2019-nCoV need to be revised. By using time-dependent contact and diagnose rates, we refit our previously proposed dynamics transmission model to the data available until January 29th, 2020 and re-estimated the effective daily reproduction ratio that better quantifies the evolution of the interventions. We estimated when the effective daily reproduction ratio has fallen below 1 and when the epidemics will peak. Our updated findings suggest that the best measure is persistent and strict self-isolation. The epidemics will continue to grow, and can peak soon with the peak time depending highly on the public health interventions practically implemented.

A. Giddens

G. C. Williams

B. Bernstein

W. Blanckenhorn

It is widely agreed that fecundity selection and sexual selection are the major evolutionary forces that select for larger body size in most organisms. The general, equilibrium view is that selection for large body size is eventually counterbalanced by opposing selective forces. While the evidence for selection favoring larger body size is overwhelming, counterbalancing selection favoring small body size is often masked by the good condition of the larger organism and is therefore less obvious. The suggested costs of large size are: (1) viability costs in juveniles due to long development and/or fast growth; (2) viability costs in adults and juveniles due to predation, parasitism, or starvation because of reduced agility, increased detectability, higher energy requirements, heat stress, and/or intrinsic costs of reproduction; (3) decreased mating success of large males due to reduced agility and/or high energy requirements; and (4) decreased reproductive success of large females and males due to late reproduction. A review of the literature indicates a substantial lack of empirical evidence for these various mechanisms and highlights the need for experimental studies that specifically address the fitness costs of being large at the ecological, physiological, and genetic levels. Specifically, theoretical investigations and comprehensive case studies of particular model species are needed to elucidate whether sporadic selection in time and space is sufficient to counterbalance perpetual and strong selection for large body size.

Pei-Chih Lee, Yuqing Yang, Kaywalee Chatdarong et al.

IntroductionDry-preservation of gametes offers a promising alternative to cryobanking by potentially storing cells at ambient temperatures; however, successful preservation of whole oocytes remains limited by dehydration-induced cellular damages. This study evaluated whether intracellular delivery of trehalose via a membrane-permeable derivative, trehalose hexaacetate (6-O-Ac-Tre), could enhance dehydration tolerance of domestic cat cumulus–oocyte complexes (COCs), a relevant model for mammalian fertility preservation.MethodsCat COCs were incubated with 0, 3, 10, or 30 mM of 6-O-Ac-Tre to assess intracellular trehalose incorporation and cytotoxicity. Non-cytotoxic doses (3 and 10 mM) were then tested for their ability to mitigate cellular damage following 10 or 15 min of microwave-assisted drying and rehydration, with outcomes including DNA integrity, mitochondrial membrane potential, cell membrane integrity, and meiotic maturation competence.ResultsOvernight exposure to 6-O-Ac-Tre enabled dose-dependent intracellular accumulation of trehalose. However, cytotoxicity examination revealed that prolonged exposure to 30 mM 6-O-Ac-Tre reduced survival and oocytes’ meiotic and developmental competence (p < 0.05). Although DNA integrity was largely preserved after drying (p > 0.05), meiotic maturation of oocytes was severely compromised (p < 0.05). Pre-incubation with 3 or 10 mM 6-O-Ac-Tre did not mitigate (p > 0.05) a reduction in mitochondrial membrane potential, cell membrane integrity, and meiotic competence.DiscussionThese findings demonstrated that, while 6-O-Ac-Tre effectively delivered trehalose into COCs, this approach did not improve dehydration tolerance of whole oocytes under the conditions tested. Collective results reflected limitations of the 6-O-Ac-Tre delivery strategy owing to its potential cytotoxicity at higher concentrations. Alternative trehalose delivery conditions or approaches need to be explored to facilitate the development of effective dry-preservation strategies for oocytes.

Marisa R. Imbroane, Hanna Kim, Elliott G. Richards

ABSTRACT Background and Aims To assess the risk of developing postpartum mood and anxiety disorders (PMAD) in patients who conceive via assisted reproductive technology (ART) versus naturally and to evaluate differences stratified by race and ethnicity. Methods This retrospective cohort study was conducted using the TriNetX research network (> 100 million patients from 68 United States health care organizations). The ART group was defined using ICD‐10 code O09.81 (“supervision of pregnancy resulting from assisted reproductive technology”) and was compared against non‐ART pregnant, age, race, ethnicity, and history of mental health condition‐matched, non‐ART, controls, all of whom reached term gestation. The relative risk of developing PMAD within 12 months of delivery was investigated. Results There were 43,103 patients in the ART group and 1,296,725 patients in the non‐ART group. Patients who conceived with ART were at a small but statistically increased risk for developing a depressive mood composite: postpartum depression, major depressive disorder, and depressive episode (5.9% vs 4.6%, RR 1.28 [95% CI (1.23,1.34)]), postpartum depression on its own (3.9% vs 3.4%, RR 1.13 (1.07,1.18)), and anxiety in the postpartum period (1.8% vs 1.2%, RR 1.56 [1.45,1.67]). These differences persisted when matching for both female infertility and obstetric complications. Within the ART group, Asian patients were significantly less likely than White patients to be diagnosed with all three outcomes. Conclusions While patients who conceive via ART are at a slightly increased risk for PMAD, the difference is small and arguably not clinically significant. This may be related to the psychological burden and stress of an infertility diagnosis and infertility treatment. Mental health services should be offered to patients being seen in ART practice.

Stephanie A. Shea, Matthew Gonnerman, Erik Blomberg et al.

ABSTRACT Pathogens can regulate or decimate free‐ranging wildlife populations. Wild turkeys (Meleagris gallopavo), which are widespread across the United States, southern Canada, and northern and central Mexico, are a prized upland gamebird that has experienced dramatic population growth and range expansion as the result of reintroduction campaigns. While increased abundance may promote disease transmission, little is known about the effects of pathogen infections on demographic metrics in wild turkeys. Lymphoproliferative disease virus (LPDV) and reticuloendotheliosis virus (REV) are oncogenic retroviruses that infect poultry and wild turkeys and can result in disease and mortality, though most infected individuals appear asymptomatic. We investigated whether retroviral infections influence wild turkey fitness by evaluating effects on female survival and several reproduction metrics. We live‐captured 163 female wild turkeys throughout central Maine, USA during three winters, from 2018 to 2020. We collected blood for LPDV and REV molecular diagnostics and attached a GPS or VHF transmitter to monitor survival and nesting. Infection with REV was associated with nearly half the cumulative annual survival probability, while LPDV‐infected hens laid an average of 1.4 fewer eggs per clutch. We detected no effects of retroviral infection on nest initiation, nesting propensity, or hatch rate, and coinfection was not associated with any measured demographic metric. These findings demonstrate that retroviral infections can negatively affect survival and clutch size in female wild turkeys even in the absence of overt disease, highlighting the importance of considering pathogen effects when evaluating the population dynamics of free‐ranging wildlife.

Jiwon Wi, Taehee Kim, Junki Kim

Stabilized optical frequency references (OFRs) are indispensable for atom-based quantum technologies, optical communications, and precision metrology. As these systems become more sophisticated, demands for compactness, robustness, and straightforward reproduction have grown. In this work, we present a robust 19-inch rack-mountable OFR module designed via a web-based CAD workflow that allows straightforward redistribution and reproduction. Its optical subsystem, designed based on a modeled laser beam path, places optical elements with sub-millimeter accuracy on a custom-machined aluminum plate, allowing straightforward assembly without extensive alignment and providing high mechanical stability. The module maintains frequency-stable operation for several months without user intervention and exhibits high robustness to mechanical vibrations up to 4g. All design files, including mechanical and optical metadata, are openly shared for straightforward reproduction and adaptation.

Sapir Goldring, Zamir Ben Hur, David Lou Alon et al.

Binaural reproduction methods aim to recreate an acoustic scene for a listener over headphones, offering immersive experiences in applications such as Virtual Reality (VR) and teleconferencing. Among the existing approaches, the Binaural Signal Matching (BSM) algorithm has demonstrated high quality reproduction due to its signal-independent formulation and the flexibility of unconstrained array geometry. However, this method assumes far-field sources and has not yet been investigated for near-field scenarios. This study evaluates the performance of BSM for near-field sources. Analysis of a semi-circular array around a rigid sphere, modeling head-mounted devices, show that far-field BSM performs adequately for sources up to approximately tens of centimeters from the array. However, for sources closer than this range, the binaural error increases significantly. Incorporating a near-field BSM design, which accounts for the source distance, significantly reduces the error, particularly for these very-close distances, highlighting the benefits of near-field modeling in improving reproduction accuracy.

Tracey Hammer, Pierre Bize, Benoit Gineste et al.

When approached by predators, prey must decide whether to flee or remain and fight. The economics of such decisions are underlain by the trade-off between current and residual fitness. The trade-off predicts that (i) breeders should be less prone than non-breeders to flee from approaching predators, as breeders can lose their investment into current reproduction; (ii) among breeders, parents should increasingly defend their offspring with increasing investment into the brood (brood value hypothesis), at least until the offspring can independently take part in anti-predator defenses; and (iii) for a similar investment into reproduction, breeders with lower perspectives to fledge or wean their young should invest less into offspring defense. We tested these predictions in a colonially breeding seabird, the king penguin (Aptenodytes patagonicus). Specifically, we considered how antipredator behaviors varied according to life history stage (molting, courting, breeding), offspring age and their dependence on parents for antipredator defenses, and the timing of breeding, with late breeders being very unlikely to fledge offspring in this species. Using non-lethal human approaches to mimic the threat of predation, we approached >500 penguins and measured their alert and flight initiation distances, as well as the distance fled. We found that birds show increasingly stronger antipredator behaviors as they initiate and increase their investment into reproduction, from non-reproductive stages to courting and brooding small, thermo-dependent chicks. However, once offspring gained thermal independence and freedom of movement, parents reduced their antipredator behaviors. Late breeders were more likely to flee from the approaching threat than early breeders. Altogether, our results demonstrate that parental antipredator responses are dynamic and shaped by the levels 3 of investment into current reproduction, the ability of offspring to defend themselves, and the perceived future value of the brood.

Anya Belz

Reproduction studies reported in NLP provide individual data points which in combination indicate worryingly low levels of reproducibility in the field. Because each reproduction study reports quantitative conclusions based on its own, often not explicitly stated, criteria for reproduction success/failure, the conclusions drawn are hard to interpret, compare, and learn from. In this paper, we present QRA++, a quantitative approach to reproducibility assessment that (i) produces continuous-valued degree of reproducibility assessments at three levels of granularity; (ii) utilises reproducibility measures that are directly comparable across different studies; and (iii) grounds expectations about degree of reproducibility in degree of similarity between experiments. QRA++ enables more informative reproducibility assessments to be conducted, and conclusions to be drawn about what causes reproducibility to be better/poorer. We illustrate this by applying QRA++ to three example sets of comparable experiments, revealing clear evidence that degree of reproducibility depends on similarity of experiment properties, but also system type and evaluation method.

Na Zhang, Jinsheng Tao, Qifang Yu et al.

Background: Global warming poses significant challenges to aquaculture, as elevated water temperatures adversely affect fish health and survival. This study investigated the effects and potential mechanisms of dietary tea polyphenols (TPs) on acute heat stress and survival in hybrid crucian carp HCC2. Methods: The fish in the control (CON) group and heat stress group (HS group, three replicates, each containing 20 fish, <i>n</i> = 60 per group) were fed diets with 0 mg/kg TPs, and the three experimental groups (HSLTP, HSMTP, and HSHTP, <i>n</i> = 20 × 3 replicates) were fed the diets with 100, 200, or 400 mg/kg TPs for 60 days. Further, fish in the experimental groups (HS, HSLTP, HSMTP, and HSHTP) were exposed at 38 °C for 24 h to induce acute heat stress. Survival data and serum and tissue samples were collected for the analysis. Metabolomics using UPLC-Q-TOF/MS was employed to evaluate the metabolite changes in the fish livers. Results: Notably, dietary TPs significantly improved survival rates and antioxidant enzyme levels and reduced serum ALT, AST, cortisol, glucose, MDA, and liver HSP-70 levels in the heat-stressed fish. Metabolomic analysis revealed that TPs modulated lipid metabolism, particularly glycerophospholipid and arachidonic acid pathways, which may contribute to a higher tolerance to acute heat stress. Conclusions: These findings suggest that TPs are a promising, eco-friendly feed additive for protecting fish from heat stress and optimizing aquaculture practices.

Olubisi Oluseun Oyeleye, Adelani Abayomi Adeoye, Thomas Ayodele Fatoba

Efficient reproduction is paramount for the sustainability and profitability of poultry enterprises. This study examined the influence of breed on semen quality traits in four chicken breeds commonly found in Nigeria, namely White Yaffa, Noiler, Yoruba ecotype and Fulani ecotype. A total of 40-day-old male chicks were used in the experiment, with 10 birds per breed. The birds were raised to 26 weeks before semen was collected. Mature cocks from each breed were subjected to semen collection and evaluation, with emphasis on both qualitative and quantitative parameters such as semen volume, color, viscosity, odor, motility, viability, and morphological characteristics. The findings revealed significant differences among the breeds studied (p <0.05). Noiler cocks recorded the highest semen volume (0.52 ± 0.04 mL) while the indigenous Yoruba ecotype produced the lowest semen volume (0.31 ± 0.01 mL). White Yaffa performed best with the highest fast progressive motility (80.33%), followed by Noiler, Fulani, and lastly Yoruba respectively at p <0.05. The sperm counts showed that Fulani had the highest concentration (1.33×10⁹/mL), followed by White Yaffa (1.23×109/mL) and Yoruba (1.11×109/mL). Noiler, in spite of its large semen volume, had the lowest sperm concentration (0.67×109/mL). Despite this variation, all breeds displayed normal semen color, viscosity, and odor, reflecting general semen viability across the groups. In conclusion, this study highlights the importance of breed as a determining factor in semen quality of male chickens. The findings from this study provides useful insight for poultry breeders, researchers and farmers in selecting suitable breeds for breeding programs.

Jingkao Tan, Na Li, Qulan Zhou et al.

Obtaining an accurate temperature distribution in furnaces for industrial combustion devices is critical. Acoustic pyrometry (AP) is a promising methodology for high-quality temperature field reconstruction, which is widely used in the monitoring of atmosphere, room, and furnace. However, due to the harsh working environment and the engineering limitations, the number of installed acoustic transducers is restricted, which in turn results in sparse valid data and an ill-posed AP problem. We used multiple means of improvement to improve the reconstruction performance of AP in a gradual and systematic manner. The fast finite-difference shooting method, the adaptive grid evolution strategy (AGES) and the radial basis function approximation with polynomial reproduction (RBFPR) were proposed and integrated into the sequential process optimization approach we concluded to systematically improve the reconstruction performance over the initial algorithm. In this approach, we optimized the parameters used for the reconstruction sequentially, analyzed the effectiveness of various means of improvement, finalized and validated an algorithm that takes into account universality and precision. Qualitative and quantitative analyses of the simulation and experimental results show the validity of the finalized algorithm and the sequential process optimization approach, demonstrating its significance for furnace temperature field measurement, combustion control, and environmental protection.

F. Engelmann

Serik Sagitov, Yerakhmet Zhumayev

We consider a special class of Galton-Watson theta-processes in a varying environment fully defined by four parameters, with two of them $(θ,r)$ being fixed over time $n$, and the other two $(a_n,c_n)$ characterizing the altering reproduction laws. We establish a sequence of transparent limit theorems for the theta-processes with possibly defective reproduction laws. These results may serve as a stepping stone towards incisive general results for the Galton-Watson processes in a varying environment.

Achraf Zinihi, Mostafa Tahiri, Moulay Rchid Sidi Ammi

In this chapter, we consider a reaction-diffusion SVIR infection model with dis-tributed delay and nonlinear incidence rate. The wellposedness of the proposed model is proved. By means of Lyapunov functionals, we show that the disease-free equilibrium state is globally asymptotically stable when the basic reproduction number is less or equal than one, and that the disease endemic equilibrium is globally asymptotically stable when the basic reproduction number is greater than one. Numerical simulations are provided to illustrate the obtained theoretical results.

Zhou Wu, Matthew M. Hindle, Valerie R. Bishop et al.

Abstract The potentially devastating effects of climate change have raised awareness of the need to understand how the biology of wild animals is influenced by extreme-weather events. We investigate how a wild arctic-breeding bird, the Lapland longspur (Calcarius lapponicus), responds to different environmental perturbations and its coping strategies. We explore the transcriptomic response to environmental adversity during the transition from arrival at the breeding grounds to incubation on the Arctic tundra. The effects of an extremely cold spring on arrival and a severe storm during incubation are examined through RNA-seq analysis of pertinent tissues sampled across the breeding cycle. The stress response, circadian rhythms, reproduction, and metabolism are all affected. A key gene of the Hypothalamic-Pituitary-Adrenal axis, FKBP5, was significantly up-regulated in hypothalamus. The genome assembly and gene expression profiles provide comprehensive resources for future studies. Our findings on different coping strategies to chronic and acute stressors will contribute to understanding the interplay between changing environments and genomic regulation.

Orken Mamyrbayev, Keylan Alimhan, Dina Oralbekova et al.

In this study, we investigated the use of the pre-sowing electrophysical stimulation of seeds, particularly focusing on optimizing technological regimes for enhancing seed quality. The aim of this study was to improve sunflower seed germination utilizing laser optical radiation. The methods explored involved the pre-sowing stimulation of oilseeds and analyzing the key mechanisms affecting germination. Through our experimental research, we sought to identify the most effective laser irradiation parameters, ensuring the maximum seed quality improvement with minimal energy use. Using seeds of the first reproduction, we employed artificial aging to simulate a reduced seed quality and determined optimal irradiation regimes. Standard methods were followed to assess seed quality before and after irradiation, with 6–7 days of further exposure. Seed germination was carried out under controlled light and temperature conditions using the “on paper” method with paper napkins. A full factorial experiment was performed and key parameters for laser irradiation were determined, confirming that the pre-sowing laser pulse treatment significantly improved seed quality. In this research, we developed a biotechnical system for processing seeds and propose a method to adjust irradiation parameters based on the initial seed quality. The system effectively enhanced germination and crop yield, offering a reliable solution for improving sunflower seed productivity through laser treatment.