Reachability in Fixed VASS: Expressiveness and Lower Bounds

The recent years have seen remarkable progress in establishing the complexity of the reachability problem for vector addition systems with states (VASS), equivalently known as Petri nets. Existing work primarily considers the case in which both the VASS as well as the initial and target configurations are part of the input. In this paper, we investigate the reachability problem in the setting where the VASS is fixed and only the initial configuration is variable. We show that fixed VASS fully express arithmetic on initial segments of the natural numbers. It follows that there is a very weak reduction from any fixed such number-theoretic predicate (e.g. primality or square-freeness) to reachability in fixed VASS where configurations are presented in unary. If configurations are given in binary, we show that there is a fixed VASS with five counters whose reachability problem is PSPACE-hard

Qualitative changes in the entrepreneurial sector in emerging territorial systems – Craiova case study

The goal of the present study is to analyze the complex economic processes within emerging territorial systems, developed around big cities. Economic ventures concentrated inside these urban clusters in a short span of time, and they registered a spectacular evolution, compared to the neighboring areas. Intensification of the linkages between cities with more than 300,000 inhabitants in Romania and the surrounding areas led to the individualization of territorial systems apart, with a spectacular evolution of economic-social processes, which turn those systems into the most dynamic territorial structures. The present study means to identify the causes of those complex processes within emerging territorial systems, the manner of functional organization of the space, and the causes that determine the spectacular evolution of the economic processes within emerging systems

A splitting theorem for Kahler manifolds whose Ricci tensors have constant eigenvalues

It is proved that a compact Kahler manifold whose Ricci tensor has two distinct, constant, non-negative eigenvalues is locally the product of two Kahler-Einstein manifolds. A stronger result is established for the case of Kahler surfaces. Irreducible Kahler manifolds with two distinct, constant eigenvalues of the Ricci tensor are shown to exist in various situations: there are homogeneous examples of any complex dimension n > 1, if one eigenvalue is negative and the other positive or zero, and of any complex dimension n > 2, if the both eigenvalues are negative; there are non-homogeneous examples of complex dimension 2, if one of the eigenvalues is zero. The problem of existence of Kahler metrics whose Ricci tensor has two distinct, constant eigenvalues is related to the celebrated (still open) Goldberg conjecture. Consequently, the irreducible homogeneous examples with negative eigenvalues give rise to complete, Einstein, strictly almost Kahler metrics of any even real dimension greater than 4.Comment: 18 pages; final version; accepted for publication in International Journal of Mathematic

Indoor Hibernation of <em>Helix aspersa</em> Juveniles

The “Italian” outdoor snailfarming technology assumes that both mature and juvenile snails hibernate outdoor, protected by a thin sheet of unweaved coverlet (agryl sheet). In contrast, the “French” snailfarming technology implies that only mature brown garden snails (Helix aspersa) hibernate indoor, in strictly controlled microenvironmental parameters (temperature, humidity, and ventilation). This technology may also be viable for H. aspersa juveniles. Extremely high death rates occurring in Romanian outdoor snailfarms during colder winters (>80%) imposed the need to find alternative paths for a proper hibernation of H. aspersa. Using statistical analyses, close surveillance of technological flow, and controlled microenvironmental parameters, we assessed the possibility to adapt indoor hibernation for H. aspersa juveniles. The experiments lasted for 2 years (2006–2008) and were carried out on 34,000 H. aspersa juveniles and 15,000 mature ones, using different technological flows and microenvironmental parameters (temperature, humidity, and ventilation). They were performed in two stages and involved five case studies, conducted independently in three different locations: Floreşti (Mehedinţi county), Sântuhalm (Hunedoara county), and Muntenii de Sus (Vaslui county). The first stage tested the hypothesis in relation to survival rate of mature snails, H. aspersa, in the same conditions, whereas the second stage improved the technological flow, before its extensive application. We demonstrated that noncontrolled microclimate parameters (temperature, humidity, and ventilation) and the use of straw as hibernation support induced significant differences (P < 0.01) concerning death levels of H. aspersa juveniles as compared to their indoor hibernation in semicontrolled microclimate (temperature and ventilation). In the same hibernation microclimate, mature snails exhibited higher survival levels than the juvenile ones, irrespective of technological flow and origin (P < 0.0001). We also demonstrated that juveniles’ weight loss displays a relatively constant variation (16.33–20.51%). In addition, the correlations between the individual average weight before and after hibernation were described by the same logarithmic regression. Furthermore, significantly higher survival rates of H. aspersa juveniles (P < 0.0001) have been registered when they had not been awakened during hibernation. Finally, we proved that indoor hibernation of H. aspersa juveniles in strictly controlled microenvironmental parameters (temperature, humidity, and ventilation) could represent a viable technology that improves the technological flow in outdoor snailfarming during wintertime in colder climates

Changes in the quality in tomato fruit due to home-scale freezing

The aim of the study was to evaluate the effect of home-scale freezing in the quality of tomato fruit cultivated in field conditions, in Romanian west area.Freezing is one of the oldest and most widely used methods of vegetables preservation.Tomatoes were analyzed fresh and stored frozen in domestic freezer at -180C for 2-6 months until analysis. Tomatoes were analyzed regarding moisture, sugar, lycopene content,ascorbic acid, phenolic compounds and total antioxidant capacity. Most important losses due to 6 months home-scale freezing were recorded for lycopene content (47%) followed by vitamin C content (20%), total antioxidant capacity (16%) and phenolic compounds content (13%). The freezing process has no to much effect on the nutritional compounds but for the best quality, use the tomato fruit within short time

Evaluation of tomato yield using statistical tests

The main objective of this study is to calculate the correlation existed between the NPK mineral fertilization doses on tomato yield using statistical tests (multiple regression analysis of variance, the F-test, value of R and R2 , Durbin–Watson test). A field experiment was using two tomatoes samples in different precocity steady (Export II and Ace Royal) cultivated in Romanian west area. Multiple regression analysis of variance on the influence of fertilization on the yield of Export II cultivar show that 90.28% of the production variability is due to the influence of these three macronutrients (NPK) while the yield of Ace Royal cultivar the percentage is 97.78%. The tomato yield increases with the fertilization doses and nitrogen fertilization has a major influence distinctly significant on achieving production, while the fertilization with potassium is lower but superior to phosphorus fertilization for two tomato cultivar

Psychological characteristics of elderly patients with oral diseases

The proportion of older people continues to grow worldwide. This, along with an increase in the prevalence of oral diseases, will significantly challenge health and social policy planners. Oral health is often neglected in the elderly and oral diseases associated with aging are complex, adversely affecting the quality of life. Identifying the psychopathology or the type of deviation from normality in the elderly, involves the assessment of psychological health and the operation with the psychological health major symptomatology. One of the dentist’s difficulties may be the recognition of a particular disorder in the case of an individual who is accusing a suffering state. The communication between the doctor and the elderly patient, which is the key in geriatric practice, is not optional, because it helps to achieve an efficient medical act in an appropriate, relevant and satisfactory manner for the care of the elderly patient. Discussion with the patient should be appropriate to the level of understanding of the individual elderly person. The patient’s cooperation is essential for any type of dental treatment. The biopsychosocial concept is fundamental to find an optimal treatment for oral diseases. The oral health influences the mental health of patients, changing their self-esteem, mood and satisfaction, even influencing their social life and quality of life. This is an important factor that has a direct influence on the general health and quality of life of older people, fundamental factors for “healthy aging”

The influence of total chromium soil content on the maize zinc levels, in a polluted area

Chromium compounds are highly toxic to plants and are detrimental to their growth and development. Cr is toxic to most higher plants at 100 µMKg-1 dry weight, while Zn is an essential plant nutrient. The essentiality of Zn in plants was first shown in maize. The aim of this paper was to determine the influence of Cr contamined soils on the accumulation of Zn in maize (Zea mays L.) grains, sampled from Tarnaveni area (Mures County, Romania), a well known industrial center. The heavy metals contents in soils and maize were determined by flame atomic absorption spectrometry using a ContrAA 300 spectrophotometer with high resolution continuum source. In soil, Cr contents ranged from 9.7 ppm to 80.73 ppm and Zn from 21.77 to 99.87 ppm. In corn, the values for Cr are between 0.081 to 0,11 ppm and for Zn between 44.74 to 132.66 ppm. Mathematical modeling indicates that chromium in the soil might be the one which is determining the evolution of zinc corn content

Evaluation of copper content in soil and Zea mays l. grains, in a Romanian polluted area

The heavy metal contamination of soil is one of the most pressing concerns in the debate about food security and food safety in Europe. Maize, also known as corn, constitute a staple food in many regions of the world. The aim of this paper was to determine the capacity of maize (Zea mays L.) grainstoaccumulate Cu, in order to evaluate the potential risk for human consume and to obtained informations regarding the soil pollution in this area. The studied area was Tarnaveni (Mures County, Romania). In soil, the copper content, calculated on the dry basis, ranged from 13.17 ppm to 52.96 ppm for 0-20 cm depth and from 14.01 to 44.82 ppm for 20-40 cm depth. The soil copper contents are exceeding the value of 20 ppm (the normal contents in soil, for Romania) but do not exceed the value of 100 ppm (the Alert threshold values for Romania). Regarding the copper content (mgKg-1 dry weight) in corn, the values are between 4.87 to 25.40 ppm, and five from seven samples exceed the permissible limit of copper for plants (10 mg/kg recommended by WHO). This study allows to obtain informations regarding the copper pollution level in this area

Influence of termic treatment on armoracia rusticana roots and leaves, total polyphenols content

The studies were conducted on Romanian horseradish originated from three domestic farms, located in the plains, hills and mountain areas. The localization of the horseradish plant as well as processing and temperature treatment seems to have a big effect on total polyphenols content (TPPC) of roots and leaves. The modifications of TPPC are due to the increasing and decreasing of temperature and they maintain the same profile irrespective of the locations