Five parallel channels of the Narew River (NE Poland) were hydromorphologically assessed with the River Habitat Survey (RHS) method. Four out of the five studied channels were partly separated from the functioning system of the anastomosing river by a dike for more than 20 years, and were subjected to gradual overgrowing and shallowing. In the 1990’s and in 2002, a number of renaturisation measures were implemented, restoring sufficient discharge for the channels to make them active again. The Habitat Modification Score (HMS) obtained as a result of the survey only classifies the fragment ecologically to the third class of streams with high HMS value in the case of the current main channel of the Narew River (largely formed in an artificial manner). This suggests substantial anthropogenic changes in the river channel and its vicinity. The aggregate values of the Habitat Quality Assessment (HQA) index suggest the preservation of numerous environmentally valuable elements at all of the five studied sites of the anastomosing Narew River system. This even concerns channels which remained almost separated and functioned as oxbow lakes for more than 20 years. The highest HQA values were recorded in the case of the channel constituting the main channel before the regulation, and a neighbouring regulated channel currently fulfilling the function of the main water course in this cross-section. In spite of long-term negative changes, the studied fragment of the ecosystem of the anastomosing river is distinguished by high resistance to “anthropogenic stress”, and high capacity for spontaneous restoration of a state close to the natural one. Although lotic ecosystems constitute elements of the natural environment particularly sensitive to anthropopressure, they retain the ability to regenerate for a long time, under the condition of providing them with relevant hydrological and ecological conditions.
Aircraft structures during operation are exposed to fluctuating loads caused both by aerodynamic and inertial loads. This fluctuation leads to the creation of fatigue cycles, which gradually diminish the residual durability of the structure. During the design process, the flight envelope is defined as well as the design load spectrum, which then defines the durability of the structure (often expressed in means of flight hours). However, during the operation of an individual aircraft the actual load cycles can be significantly lower or higher than the designed; therefore, load monitoring is essential for safe operation of aircraft structures.
The following article shows the results of fatigue analysis based on flight data from different flight data recorders for the Su-22 fighter aircraft.
This article presents a description of a case of a patient diagnosed with complicated inflammation of the tibia bone, who was treated hyperbarically, in order to underline the advantages of this method of treatment used not as an alternative to antibiotics and surgery, but as a supportive method.
Hydrochemical investigations focusing on different iron fractions were conducted in 2007 from January to December on two parts (regulated and restored) of the small lowland Rudnia River in north-eastern Poland. Concentrations of the total iron (TFe) in the water of the Rudnia River ranged from 582 μg dm-3 up to 3646 μg dm-3, and their elevated values are clearly the result of their complex binding with organic matter originating from the peat-mineral catchment of the river. Regardless of the season, in the upper part of the river (regulated channel) higher concentrations of all iron fractions than in the restored river section were observed. All tests on iron fractions showed a clear seasonal variability on both river channel parts. Higher TFe concentrations were typical for the regulated part of the river in autumn or winter, and lower in spring for the restored river channel section. For the whole of the investigated period and regardless of the season, particulate iron fraction (PFe) represented a higher proportion of TFe in the regulated channel than in the restored one. PFe constituted up to 60% TFe, on average, while the other two fractions about 20% of TFe each. However, dissolved reactive iron fraction (DRFe) made up a larger percentage of TFe than organic soluble fraction (DOFe) of iron within the year. The maximum percentage of DOFe fraction outside the growing season was caused by iron release from organic complexes and elevated concentrations of dissolved organic carbon (DOC) derived from wetlands.
Studies were carried out in September 2007 at a set of stations called RIVERS located on two tributaries of the Narew River, and six stations on the tributaries of the Supraśl River. Concurrently, rotifers were sampled at nine stations of the River Rudnia (called RUDNIA). The aim of the research was the verification of the hypothesis on the uniforming effect of the river drift on rotifer communities inhabiting aquatic vegetation. The total numbers of all monogonont species inhabiting aquatic vegetation of RUDNIA and RIVERS were 83 and 107, respectively. The percentage similarity of rotifer communities from aquatic vegetation and river current at the same stations was relatively low and only slightly higher in RIVERS (21.7%) than RUDNIA (17.1%), which suggests that species composition of communities of epiphytic rotifer fauna has a rather low impact on species structure of rotifer communities in water drift. The set of individuals of different species carried with the water current was random and various at different stations. Although the percentage similarity of rotifer communities in the river drift calculated for all possible pairs of the stations was relatively lower in RIVERS than in RUDNIA, it was not reflected in the similarity of epiphytic rotifer communities, which were similar in both sets of stations. Thus, the hypothesis cannot be confirmed by the results of this research.
This paper presents a case report of a patient with a diagnosed complication of a sternum wound which was treated using hyperbaric oxygen, emphasizing the truism of the benefits of combined surgical therapy, antibiotic therapy and oxybarotherapy.
Our study concerns the development of marginal zone of Lake Suchar Wielki (Wigry National Park). This humic lake is characterised by mire occurrence in its marginal zone, covered with a floating mat spreading on water surface. Biogenic sediments (peat archive) present in lakeside allow recognising the thousands years’ development pattern of lake surrounded by mire. The wetland records were analysed for plant macroremains, degree of peat decomposition, sediment geochemical features along with age assessment. Morphological characteristics of the catchment were integrated with the wetland records. Our research showed that after the lake origin in the Allerod, accumulation in its marginal zone was interrupted, which was probably connected with high precipitation in the past. Slope processes could be possible. Stabilisation of environmental conditions took place in the younger Holocene. Despite these perturbations marginal zone of the lake was permanently terrestrial in character, as indicated by values of atomic C:N ratio.
Introduction. Pathological muscle tone can cause changes in the facial skeleton, including tension headaches, tinnitus, temporomandibular joint dysfunctions. The complexity of pathologies and their spectrum may also indicate changes beyond the facial skeleton. The aim of the study was to determine the possible correlation between the pressure pain threshold of the trapezius muscle and the bioelectrical tension on the masticatory muscles.
Aim. The aim of the study was to determine the possible correlation between the pressure pain threshold of the trapezius muscle and the bioelectric tension on the masticatory muscles.
Material and methods. The number of 36 women applied for the study. They were all examined using an algometer within a trapezius muscle to determine the pressure pain threshold. The electromyographic study was carried out in accordance with the SENIAM guidelines. The resting activity of selected masticatory muscles (temporal and masseter) was recorded for 10 sec. The study involved an 8-channel BioEMG IIITM surface electromyography apparatus with BioPak Measurement System (BioResearch Associates, Inc. Milwaukee, WI, USA). Statistical analysis was carried out using the r-Pearson test. The level of significance was set at 5%.
Results. After comparing the bioelectric tension of the masticatory muscles and the pressure pain threshold, left-sided correlation was observed (p<0.05). Both in the right-hand and general comparison, the results did not reach the required level of statistical significance (p>0.05).
Conclusions. The pressure pain threshold seems to be linked to the bioelectrical muscle tone of the masticatory muscles. To confirm this observation, further research into a larger and more diverse group of participants is recommended.
This article presents a concept of the full scale fatigue test of a Su-22 fighter bomber. The authors define the general concept and goals of the test as well as the tasks to be accomplished in the preparation stage. The current work status is summarized and future tasks are defined.