In their natural environment, animals face a variety of ecological and social challenges, which might be linked to the emergence of different cognitive skills. To assess inter-specific variation in cognitive skills, we used ungulates as a study model, testing a total of 26 captive individuals across 5 different species (i.e., dwarf goats, Capra aegagrus hircus, llamas, Lama glama, guanacos, Lama guanicoe, zebras, Equus grevyi, and rhinos, Diceros bicornis michaeli). Across species, we used the same well-established experimental procedures to test individuals\' performance in naïve physics tasks, i.e. object permanence, short-term spatial memory, causality, understanding of object properties, and gravity. Our results revealed that study subjects showed object permanence, were able to remember the position of hidden food after up to 60 s, and inferred the position of hidden food from the sound produced or not produced when shaking containers. Moreover, they showed an understanding of basic object properties, being able to locate objects hidden behind occluders based on their size and inclination, and could reliably follow the trajectory of falling objects across different conditions. Finally, inter-specific differences were limited to the understanding of object properties, and suggest that domesticated species as goats might perform better than non-domesticated ones in tasks requiring these skills. These results provide new information on the cognitive skills of a still understudied taxon and confirm ungulates as a promising taxon for the comparative study of cognitive evolution.

Metronomic chemotherapy refers to the frequent administration of chemotherapeutic agents at a lower dose and presents an attractive alternative to conventional chemotherapy with encouraging response rates. However, the schedule of the therapy, including the dosage of the drug, is usually based on empiricism. The confounding effects of tumor-endothelial-immune interactions during metronomic administration of drugs have not yet been explored in detail, resulting in an incomplete assessment of drug dose and frequency evaluations. The present study aimed to gain a mechanistic understanding of different actions of metronomic chemotherapy using a mathematical model. We have established an analytical condition for determining the dosage and frequency of the drug depending on its clearance rate for complete tumor elimination. The model also brings forward the immune-mediated clearance of the tumor during the metronomic administration of the chemotherapeutic agent. The results from the global sensitivity analysis showed an increase in the sensitivity of drug and immune-mediated killing factors toward the tumor population during metronomic scheduling. Our results emphasize metronomic scheduling over the maximum tolerated dose (MTD) and define a model-based approach for approximating the optimal schedule of drug administration to eliminate tumors while minimizing harm to the immune cells and the patient\'s body.

This research paper delves into the two-dimensional discrete plant-herbivore model. In this model, herbivores are food-limited and affect the plants\' density in their environment. Our analysis reveals that this system has equilibrium points of extinction, exclusion, and coexistence. We analyze the behavior of solutions near these points and prove that the extinction and exclusion equilibrium points are globally asymptotically stable in certain parameter regions. At the boundary equilibrium, we prove the existence of transcritical and period-doubling bifurcations with stable two-cycle. Transcritical bifurcation occurs when the plant\'s maximum growth rate or food-limited parameter reaches a specific boundary. This boundary serves as an invasion boundary for populations of plants or herbivores. At the interior equilibrium, we prove the occurrence of transcritical, Neimark-Sacker, and period-doubling bifurcations with an unstable two-cycle. Our research also establishes that the system is persistent in certain regions of the first quadrant. We demonstrate that the local asymptotic stability of the interior equilibrium does not guarantee the system\'s persistence. Bistability exists between boundary attractors (logistic dynamics) and interior equilibrium for specific parameters\' regions. We conclude that changes to the food-limitation parameter can significantly alter the system\'s dynamic behavior. To validate our theoretical findings, we conduct numerical simulations.

BACKGROUND: Considering the high maternal mortality rate, the government of Pakistan has deployed Community Midwives (CMWs) in rural areas of Pakistan. This relatively new cadre of community-based skilled birth attendants has previously reported to experience several challenges in providing maternal and child healthcare. However, what barriers they experience in providing basic emergency obstetric and newborn care needs to be further studied.
METHODS: This was a cross-sectional study conducted in twelve districts in Sindh province, Pakistan, with poor maternal and child health indicators. A total of 258 CMWs participated in this study and completed the questionnaire on a pretested, validated tool in their community-based stations. The trained data collectors completed the questionnaires from the respondents. The problems identified were categorized into three major issues: financial, and transport and security related; and were analyzed accordingly. Ethical approval was obtained from the institutional review board (IRB) of Health Services Academy (HSA) Islamabad, Pakistan.
RESULTS: The majority (90%) of 258 CMWs had formal training in maternal and neonatal care from the recognized institutions. Financial difficulties faced by CMWs were identified as the most frequent barriers and others were transport, security, and other issues. In univariate analysis, 38.1% and 61.9% of the community midwives who faced financial difficulties had completed a graduation or intermediate level of education, respectively (p = 0.006). Round-the-clock availability for emergencies was inversely associated with having financial difficulties, i.e., 71.4%, in contrast to 28.4% who had financial difficulties were available round-the-clock for emergency calls in their community clinics (p = 0.008). Formal training (p = 0.001), work experience (p = 0.015), longer duration of work (p = 0.003), and liaison with health workers and posting district (p = 0.001) had statistically significantly higher transport related issues. Security difficulties faced by CMWs and a set of correlates such as formal training (p = 0.019), working experience (p = 0.001), longer duration of work (p = 0.023), 24 h of availability on call (p = 0.004), liaison with traditional birth attendants (TBAs) in the community (p = 0.002), and district of posting (p = 0.001) were statistically significantly different. Other issues like working experience (p = < 0.001) and Liaison with TBAs in the community (p = < 0.001) were found statistically significant.
CONCLUSIONS: Financial, transportation and security related barriers were commonly reported by community midwives in the delivery of basic emergency obstetric and newborn care in rural Pakistan.

In this work, we set up a new discrete predator-prey competitive model with time-varying delays and feedback controls. By virtue of the difference inequality knowledge, a sufficient condition which guarantees the permanence of the established discrete predator-prey competitive model with time-varying delays and feedback controls is derived. Under some appropriate parameter conditions, we have proved that the periodic solution of the system without delay exists and globally attractive. To verify the correctness of the derived theoretical fruits, we give two examples and execute computer simulations. Our obtained results are novel and complement previous known results.

Increasing soil organic carbon (SOC) stocks in agricultural soils removes carbon dioxide from the atmosphere and contributes towards achieving carbon neutrality. For farmers, higher SOC levels have multiple benefits, including increased soil fertility and resilience against drought-related yield losses. However, increasing SOC levels requires agricultural management changes that are associated with costs. Private soil carbon certificates could compensate for these costs. In these schemes, farmers register their fields with commercial certificate providers who certify SOC increases. Certificates are then sold as voluntary emission offsets on the carbon market. In this paper, we assess the suitability of these certificates as an instrument for climate change mitigation. From a soils\' perspective, we address processes of SOC enrichment, their potentials and limits, and options for cost-effective measurement and monitoring. From a farmers\' perspective, we assess management options likely to increase SOC, and discuss their synergies and trade-offs with economic, environmental and social targets. From a governance perspective, we address requirements to guarantee additionality and permanence while preventing leakage effects. Furthermore, we address questions of legitimacy and accountability. While increasing SOC is a cornerstone for more sustainable cropping systems, private carbon certificates fall short of expectations for climate change mitigation as permanence of SOC sequestration cannot be guaranteed. Governance challenges include lack of long-term monitoring, problems to ensure additionality, problems to safeguard against leakage effects, and lack of long-term accountability if stored SOC is re-emitted. We conclude that soil-based private carbon certificates are unlikely to deliver the emission offset attributed to them and that their benefit for climate change mitigation is uncertain. Additional research is needed to develop standards for SOC change metrics and monitoring, and to better understand the impact of short term, non-permanent carbon removals on peaks in atmospheric greenhouse gas concentrations and on the probability of exceeding climatic tipping points.

Paper recycling is a viable option for wastepaper management. This study assessed the suitability of recycled papers as a food packaging material. Permanence and durability of three different recycled papers; R1:150 GSM, R2:120 GSM, and R3:100 GSM with aging were evaluated using standard methods. Eventhough opacity increased with aging grammage, burst strength, tensile strength, pH, brightness, and whiteness decreased. Recycled papers failed water absorptiveness test even before aging. Presence of heavy metals in recycled papers were compared with food packaging standards and migration of heavy metals from the packaging to different food types was assessed. Presence of Cu, Zn, Mn, Cr, Cd and Pb were below EC and EPA standards but only Pb and Cd exceeded the EU standard. Migration of Cu, Zn, Mn and Cr were within EPA, EU and EC standards except Pb and Cd with respect to EC standard. Highest migration is associated with foods contain more fatty acids; fast food, sausages and pizza.

To understand the mechanisms underlying species coexistence, ecologists often study invasion growth rates of theoretical and data-driven models. These growth rates correspond to average per-capita growth rates of one species with respect to an ergodic measure supporting other species. In the ecological literature, coexistence often is equated with the invasion growth rates being positive. Intuitively, positive invasion growth rates ensure that species recover from being rare. To provide a mathematically rigorous framework for this approach, we prove theorems that answer two questions: (i) When do the signs of the invasion growth rates determine coexistence? (ii) When signs are sufficient, which invasion growth rates need to be positive? We focus on deterministic models and equate coexistence with permanence, i.e., a global attractor bounded away from extinction. For models satisfying certain technical assumptions, we introduce invasion graphs where vertices correspond to proper subsets of species (communities) supporting an ergodic measure and directed edges correspond to potential transitions between communities due to invasions by missing species. These directed edges are determined by the signs of invasion growth rates. When the invasion graph is acyclic (i.e. there is no sequence of invasions starting and ending at the same community), we show that permanence is determined by the signs of the invasion growth rates. In this case, permanence is characterized by the invasibility of all [Formula: see text] communities, i.e., communities without species i where all other missing species have negative invasion growth rates. To illustrate the applicability of the results, we show that dissipative Lotka-Volterra models generically satisfy our technical assumptions and computing their invasion graphs reduces to solving systems of linear equations. We also apply our results to models of competing species with pulsed resources or sharing a predator that exhibits switching behavior. Open problems for both deterministic and stochastic models are discussed. Our results highlight the importance of using concepts about community assembly to study coexistence.

Autocatalytic systems called hypercycles are very often incorporated in \"origin of life\" models. We investigate the dynamics of certain related models called bimolecular autocatalytic systems. In particular, we consider the dynamics corresponding to the relative populations in these networks, and show that it can be analyzed using well-chosen autonomous polynomial dynamical systems. Moreover, we use results from reaction network theory to prove persistence and permanence of several families of bimolecular autocatalytic systems called autocatalytic recombination systems.

We consider an age-structured density-dependent population model on several temporally variable patches. There are two key assumptions on which we base model setup and analysis. First, intraspecific competition is limited to competition between individuals of the same age (pure intra-cohort competition) and it affects density-dependent mortality. Second, dispersal between patches ensures that each patch can be reached from every other patch, directly or through several intermediary patches, within individual reproductive age. Using strong monotonicity we prove existence and uniqueness of solution and analyze its large-time behavior in cases of constant, periodically variable and irregularly variable environment. In analogy to the next generation operator, we introduce the net reproductive operator and the basic reproduction number [Formula: see text] for time-independent and periodical models and establish the permanence dichotomy: if [Formula: see text], extinction on all patches is imminent, and if [Formula: see text], permanence on all patches is guaranteed. We show that a solution for the general time-dependent problem can be bounded by above and below by solutions to the associated periodic problems. Using two-side estimates, we establish uniform boundedness and uniform persistence of a solution for the general time-dependent problem and describe its asymptotic behaviour.