A mechanism of abiogenesis based on complex reaction networks organized by seed-dependent autocatalytic systems

The core of the origin-of-life problem is to explain how a complex dissipative system could emerge spontaneously from a simple environment, perpetuate itself, and complexify over time. This would only be possible, we argue, if prebiotic chemical reaction networks had autocatalytic features organized in a way that permitted the accretion of complexity even in the absence of genetic control. To evaluate this claim, we developed tools to analyze the autocatalytic organization of food-driven reaction networks and applied these tools to both abiotic and biotic networks. Both networks contained seed-dependent autocatalytic systems (SDASs), which are subnetworks that can use a flux of food chemicals to self-propagate if, and only if, they are first seeded by some non-food chemicals. Moreover, SDASs were organized such that the activation of a lower-tier SDAS could render new higher-tier SDASs accessible. The organization of SDASs is, thus, similar to trophic levels (producer, primary consumer, etc.) in a biological ecosystem. Furthermore, similar to ecological succession, we found that higher-tier SDASs may produce chemicals that enhance the ability of the entire chemical ecosystem to utilize food more efficiently. The SDAS concept explains how driven abiotic environments, namely ones receiving an ongoing flux of food chemicals, can incrementally complexify even without genetic polymers. This framework predicts that it ought to be possible to detect the spontaneous emergence of life-like features, such as self-propagation and adaptability, in driven chemical systems in the laboratory. Additionally, SDAS theory may be useful for exploring general properties of other complex systems.

ENSURING THE STABILITY OF INTERNAL DUMPS ACCORDING TO THE RESULTS OF PHYSICAL AND MECHANICAL PARAMETERS OF SOILS

Purpose. The paper considers the issues of ensuring the stability of internal dumps consisting of soft rocks. This issue is relevant because the stability of quarry boards and dumps affects the safety of work in quarries. Methodology. When assessing the stability of slopes, the method of determining the minimum coefficient of stability, equal to the ratio of restraining forces to shear forces that arise in the slope array. Findings. The calculation and assessment of the stability of the slopes of the dumps are carried out on the example of Malyshevsky rutile-zircon-ilmenite deposit. The geological structure of the deposit overburden is represented by loess-like loams, red-brown clays, gray-green clays, fine-grained sands. To ensure the stability of internal dumps, the selective formation of dumps is proposed, which is presented in this paper in two ways. In the first variant, the dumping of Sarmatian gray-green clays into the lower part of the heap, which are weakly permeable and have low strength, is considered. In the second variant, a layer of Sarmatian sands is poured into the base of the dump. According to the normative value of the coefficient of stability margin, depending on the physical and mechanical properties of the rocks that make up the array, the optimal height and slope angle of the dump are determined. When assessing the stability of the slopes of the dump, the impact of groundwater and the possibility of location in the developed space of the tailings were also taken into account. Originality and Practical implications. Studies have shown that the most rational option is the formation of internal heaps with embedding in the base of the lower tier of the heap with a height of 40 m layer of Sarmatian sands; in the case of embedding in the lower part of the inner heaps of gray-green clays, it is advisable to form the lower tier of the heap with 2 sub-tiers up to 20 m high; the upper tier of the dump is recommended to be formed by one massif 26 m high. Besides, in the produced space of the quarry, the location of the tailings is possible in case of dumping Sarmatian sands into the base of the dump.

RELIEF AND GEOLOGICAL STRUCTURE OF CARPATHIAN BIOSPHERE RESERVE

The relief and geological structure of Carpathian Biosphere Reserve represent the features of the geological and geomorphological structure of the four geomorphological regions of the Ukrainian Carpathians. The block mid-mountains of the Polonynsko-Chornohirsky Carpathians (Chornohora, Svydovets, and Uholsko-Shyrokoluzhansky massifs) and the folded mid-mountains of Marmarosy crystal massif (Marmarosy and Kuziy-Trybushansky massifs) are well protected within the reserve. The analysis of the morphostructure and morphosculpture of the reserve is carried out taking into account the longitudinal (NW–SE) and transverse divisions of the Ukrainian The analysis of the morphostructure and morphosculpture of the reserve is carried out taking into account the longitudinal (NW–SE) and transverse divisions of the Ukrainian Carpathians. The longitudinal division is associated with morphostructures of higher orders, such as second and third. The transverse division is associated with the fourth and fifth orders of morphostructures. In the analysis of morphosculpture of the reserve, the types characterized for all regions of Flysch and Crystal Carpathians are allocated. All mountain massifs and ridges could be characterized by an asymmetrical structure, such as steep northeastern slopes and acclivous southwestern slopes. The relic morphosculpture is represented by: 1) fragments of denudation surfaces of different ages such as Polonynska, Pidpolonynska, and riparian; 2) ancient glacial and extra glacial landforms; 3) areas of ancient longitudinal valleys. River valleys with a complex of different age terraces represent inherited morphosculpture. Modern morphodynamic processes are represented by height (tier) differentiation. The processes of sheet erosion, deflation, and rill erosion play an important role in the relief modeling for the tiers of strongly dissected mid-mountain relief. The lower tier of the terraced and non-terraced bottoms of the valleys are associated with the processes of leaching and erosion as well as a significant accumulation of erosion products and mudflows. Stabilized and active displacements are the most recorded among the gravitational processes and block motions. Key words: Carpathian Biosphere Reserve; Ukrainian Carpathians; relief; morphostructure; morphosculpture.

Comparison of the Intestinal Pharmacokinetics of Two Different Florfenicol Dosing Regimens and Its Impact on the Prevalence and Phenotypic Resistance of E. coli and Enterococcus over Time

In order to mitigate the food animal sector’s role in the growing threat of antimicrobial resistance (AMR), the World Health Organization (WHO) suggests the use of lower tier antimicrobials, such as florfenicol. Florfenicol has two dosing schemes used to treat primarily bovine respiratory disease. In this study, the objective was to characterize the plasma and gastrointestinal pharmacokinetics of each dosing regimen and assess the effect of these dosing regimens on the prevalence of resistant indicator bacteria over time. Twelve steers underwent abdominal surgery to facilitate the placement of ultrafiltration probes within the lumen of the ileum and colon, as well as placement of an interstitial probe. Following surgery, cattle were dosed with either 20 mg/kg IM every 48 h of florfenicol given twice (n = 6) or a single, subcutaneous dose (40 mg/kg, n = 6). Plasma, interstitial fluid, gastrointestinal ultrafiltrate, and feces were collected. Pharmacokinetic analysis demonstrated high penetration of florfenicol within the gastrointestinal tract for both the high and low dose group (300%, 97%, respectively). There was no significant difference noted between dosing groups in proportion or persistence of phenotypically resistant bacterial isolates; however, the percent of resistant isolates was high throughout the study period. The recommendation for the use of a lower tier antimicrobial, such as florfenicol, may allow for the persistence of co-resistance for antibiotics of high regulatory concern.

Differentiation of the content of chlorophyll, nitrogen and phosphorus in soybean leaves of different tiers

The article presents the results of determining the content of chlorophyll, nitrogen and phosphorus in the leaves of different tiers in soybean plants. The results of testing the working hypothesis about the relationship between chlorophyll content and nutrients are shown and data on the dynamics of their content in soybean leaves in the phases of bean formation, grain filling and the beginning of physiological maturity are demonstrated. The study performed during 2016 and 2017 in the field small-scale experiment of the Department of Agrochemistry of Kharkiv National Agrarian University named after V.V. Dokuchaev in the Kharkiv region of Ukraine. The soil is typical medium loam chernozem (Haplic Chernozem) with a humus content of 5.5–6.1 %, easily hydrolyzed nitrogen – 5 mg / 100 g, mobile phosphorus – 7 mg / 100 g of soil. Soybean seeds treated with the bacterial preparation rhizohumin before sowing. The content of chlorophyll in the leaves of plants determined by colorimetric method after extraction with ethyl alcohol; the total content of nitrogen and phosphorus in the plant samples is also colorimetric after burning the sample in sulfuric acid by the method of wet ashing. The results showed that during all the controlled phases of ontogenesis, the young leaves of the upper tier contained the most chlorophyll, nitrogen and phosphorus, and the leaves of the lower tier contained the least. The highest content of chlorophyll, nitrogen and phosphorus recorded in the leaves of the upper tier in the phase of bean formation, the lowest - in the leaves of the lower tier at the beginning of physiological maturity. No significant difference found between the control variant and the variants with the use of fertilizers. The method of applying the same dose of mineral fertilizers also did not significantly affect the studied indicators. This stated the presence of a characteristic feature of the accumulation and reutilization of nutrients in the leaves of different ages, located on different parts of soybean stems. A close direct correlation was found between the content of chlorophyll in soybean leaves and the content of nitrogen (r = 0.85) and phosphorus (r = 0.76). There is also a direct relationship between the content of nitrogen in the leaves of all tiers and the phosphorus content (r = 0.80).

EXITING POVERTY THROUGH SELF-EMPLOYMENT: THE GRAMEEN MODEL AND ROTATING CREDIT ASSOCIATIONS AS ALTERNATIVE STRATEGIES

Self-employment in the informal sector keeps poor people alive, but it rarely enables them to exit poverty. To exit poverty through self-employment, poor people require monetary and non-monetary resources which they overwhelmingly lack. To escape this dilemma, the owners of survivalist business firms need to band together in order to assemble a minimal resource base on the strength of which they can together upgrade their partnership. Because resources are scarce in poverty populations, this task is exceptionally hard to accomplish. Rotating credit and savings associations (ROSCAs) can enable individuals to exit poverty through self-employment, but ROSCAs only work in the most-resourced, upper tier of a poverty population. In the lower tier, Grameen model banks inject organizational, educational, and financial resources that enable impoverished individuals to exit poverty by upgrading a survivalist business.

Service Delivery To Informal Settlements In South Asia's Mega Cities: the Role Of State and Non-State Actors

This interdisciplinary research project compares service delivery outcomes to informal settlements in South Asia’s largest urban centres: Dhaka, Karachi and Mumbai. These mega cities have been overwhelmed by increasing demands on limited service delivery capacity as growing clusters of informal settlements, home to significant numbers of informal sector workers, struggle to obtain basic services. In the absence of state supports, some informal settlements engage non‐state actors to obtain services. In order to compare service delivery outcomes through these actors, I used a layered, mixed methods approach guided by an interdisciplinary literature review and policy examination. I drew on semi‐ structured interviews as well as pairs of case studies to measure successful and unsuccessful service delivery outcomes in each of the three mega cities. Key findings are that chronic disconnections exists in all three countries, where upper tiers of the state persistently fail to create an enabling environment for lower tier state actors and municipal service delivery machinery. The cause of these disconnections is the persistent colonial impression on the bureaucracy, Neoliberal policies and the appropriation of public resources by organized crime and their backers, urban elites. Non‐state actors have facilitated service delivery to informal settlements, resulting in isolated success and improved levels of human development. However, the case studies demonstrate that the success of non‐state actors is attributed to support from lower tier state actors. A complex political economy of upper and lower tier actors, rooted in unresolved land ownership and elite interests is disabling the capabilities of lower tier state actors to extend services to the urban poor. The study informs our understanding of the role played by technical non‐governmental organizations (NGOs) in facilitating representative community‐based organizations (CBOs) engagement of state service delivery providers. The study illustrates the differential attitudes between upper and lower tier state actors towards informal settlements. The study also separates the ‘development industry’ from grass root representatives of informal settlements. The study also affirms the ability of informal settlements to organize, mobilize and engage municipal service delivery providers. The study emphasizes the need to remove constraints that upper tiers of state and society place on informal settlements in order for equitable development and sustainable levels of service delivery to be realized