Early detection of phosphorus deficiency stress in cucumber at the cellular level using chlorophyll fluorescence signals

Abiotic stressors contribute to growth restriction and developmental disorders in plants. Early detection of the first signs of changes in plant functioning is very important. The objective of this study was to identify chlorophyll fluorescence parameters that change under phosphorus deficiency stress in cucumber. In this work, a trail to study the early changes caused by phosphorus deficiency in cucumber plants by analysing their photosynthetic performance is presented. Chlorophyll-a fluorescence (ChF) parameters were measured every 7 days for a period of 28 days. Measurements were made separately on young and old leaves and on cucumber fruit. Parameters that decreased during the stress were: p2G, PIabs, PItotal, REo/CSo, and TRo/CSo. P deficiency decreased total electron carriers per RC (ECo/RC), yields (TRo/ABS (Fv/Fm), ETo/TRo, REo/ETo, ETo/ABS and REo/ABS), fluxes (REo/RC and REo/CSo) and fractional reduction of PSI end electron acceptors, and damaged all photochemical and non-photochemical redox reactions. Principal component analysis revealed a group of ChF parameters that may indicate early phosphorus deficiency in cucumber plants. Our results are used in the discovery of sensitive bioindicators of phosphorus deficiency in cucumber plants. Most JIP test parameters are linked to mathematical equations, so we recommend using of advanced statistical tools, such as principal component analysis, which should be considered very useful for stress identification. It has also been shown to be more effective in multivariate methods compared to univariate statistical methods was demonstrated

Generator oscylacji chaotycznych o układzie RL- dioda jako przetwornik rezystancja - napięcie

Przedstawiono wyniki badań nad możliwością niekonwencjonalnego przetwarzania rezystancji na napięcie z wykorzystaniem nieautonomicznego generatora oscylacji chaotycznych o układzie szeregowym RL-dioda. Podano podstawowe zależności dla wartości chwilowych procesów zachodzących w tym generatorze i dokonano symulacji chaotycznego przebiegu i widma częstotliwościowego jego prądu. Zbadano też zależność wartości szczytowej spadku napięcia i czułość na zmiany rezystancji R i indukcyjności L tego generatora oraz zaprojektowano układ detektora do pomiarów amplitudy tych zmian. Uzyskano potwierdzenie, że układ z generatorem RL-dioda można będzie wykorzystać do przetwarzania rezystancji na napięcie o dużej czułości w zakresie do 250 Ω.The results of research on the possibility of unconventional resistance -voltage conversion based on use of the no autonomic serial RLdiode generator of chaotic oscillations is given.. The basic relationships of processes in the generator circuit are given and changes of its current in time and frequency are simulated. Relations between the resistance peak voltage and its sensitivity to resistance changes were examined on the designed model of this circuit. It is confirmed that this system can be used for resistance-voltage conversion with high sensitivity in the range up to 250 Ω. (RL-diode generator of chaotic oscillations as resistance – voltage converter

An investigation of heuristic decomposition to tackle workforce scheduling and routing with time-dependent activities constraints

This paper presents an investigation into the application of heuristic decomposition and mixed-integer programming to tackle workforce scheduling and routing problems (WSRP) that involve timedependent activities constraints. These constraints refer to time-wise dependencies between activities. The decomposition method investigated here is called repeated decomposition with con ict repair (RDCR) and it consists of repeatedly applying a phase of problem decomposition and sub-problem solving, followed by a phase dedicated to con ict repair. In order to deal with the time-dependent activities constraints, the problem decomposition puts all activities associated to the same location and their dependent activities in the same sub-problem. This is to guarantee the satisfaction of time-dependent activities constraints as each sub-problem is solved exactly with an exact solver. Once the assignments are made, the time windows of dependent activities are fixed even if those activities are subject to the repair phase. The paper presents an experimental study to assess the performance of the decomposition method when compared to a tailored greedy heuristic. Results show that the proposed RDCR is an effective approach to harness the power of mixed integer programming solvers to tackle the diffcult and highly constrained WSRP in practical computational time. Also, an analysis is conducted in order to understand how the performance of the different solution methods (the decomposition, the tailored heuristic and the MIP solver) is accected by the size of the problem instances and other features of the problem. The paper concludes by making some recommendations on the type of method that could be more suitable for different problem sizes

Environmental factors and allergic diseases

An objective of this article is a review of contemporary knowledge on various environmental factors, that influence prevalence and course of allergic diseases, like asthma, allergic rhinitis, atopic dermatitis and also contact dermatitis. Surrounding climate may directly influence each patient, but also determines type of flora and fauna within particular geographical regions and thus affects sources of airborne and food allergens. Epidemiological studies suggest that there is a strong relationship between air pollution and development and exacerbation of asthma and other allergic diseases – main attention has been concentrated on gaseous materials such as ozone (O3) and nitrogen dioxide (NO2), as well as particulate matter (PM), generated by car traffic and industry. Diesel exhaust particulate (DEP) has the ability to bind proteins and may serve as a potential carrier of allergens, penetrating deep into respiratory tract. Among the most extensively studied environmental factors influencing allergy are airborne allergens: dust mites, pollens, fungi and animal dander. Foods may elicit both true IgE-mediated allergy and also various non-immunological reactions, associated with direct release of mediators or toxic activity. It has been estimated, that over 85 000 chemicals are recognized in the human environment and they may act as contact allergens or irritants, causing allergic or non-allergic contact dermatitis. Among them metals, fragrances, preservatives, botanicals and paraphenylenediamine are considered as the most significant. Infections have always been associated with etiopathogenesis of allergic diseases and they may contribute to exacerbation of their course