Observation problems posed for the Klein-Gordon equation

Transversal vibrations $u=u(x,t)$ of a string of length $l$ with fixed ends are considered, where $u$ is governed by the Klein-Gordon equation $$u_{tt}(x,t) = a^2u_{xx}(x,t)+cu(x,t), \qquad (x,t) \in [0,l] \times \mathbb{R}, \quad a>0, \ c<0.$$ Sufficient conditions are obtained that guarantee the solvability of each of four observation problems with given state functions $f, \ g$ at two distinct time instants $-\infty<t_1<t_2 < \infty$. The essential conditions are the following: smoothness of $f, \ g$ as elements of a corresponding subspace $D^{s+i}(0,l)$ (introduced in [2]) of a Sobolev space $H^{s+i} (0,l)$, where $i=1,2$ depending on the type of the observation problem, and the representability of $t_2-t_1$ as a rational multiple of $\frac{2l}{a}$. The reconstruction of the unknown initial data $(u(x,0), u_t(x,0))$ as the elements of $D^{s+1}(0,l) \times D^s(0,l)$ are given by means of the method of Fourier expansions

Observability of string vibrations

Transversal vibrations $u=u(x,t)$ of a string of length $l$ under three essential boundary conditions are studied, where $u$ is governed by the Klein--Gordon equation: $$u_{tt}(x,t) = a^2u_{xx}(x,t) - cu(x,t), (x,t) \in [0,l]\times \mathbb{R}; \ 0 < a, c \in \mathbb{R}.$$ Sufficient conditions are obtained that guarantee the unique solvability of a general observation problem with the given state functions $f, g \in D^s(0,l), s \in \mathbb{R}$ at two distinct instants of time $-\infty < t_1 < t_2 < \infty$: \begin{array} \displaystyle A_1 u|_{t=t_1} + B_1 u_t|_{t=t_1} = f, & |A_1|+|B_1| > 0, \ A_1 B_1\geq 0, \\ \displaystyle A_2 u|_{t=t_2} + B_2 u_t|_{t=t_2} = g, & |A_2|+|B_2| > 0, \ A_2 B_2\leq 0. \end{array} Here $s$ is arbitrary, the space $D^s(0,l)$ (see [2] and [13]) is some subspace of the Sobolev space $H^s(0,l)$. The essential condition of the solvability is that $(t_2-t_1) a/l$ is a rational number. In fact, this result is a consequence of a general observability result related to the vibration $u = u(x,t)$ governed by the equation $$u_{tt} = (p(x) u_{x})_x - q(x) u, (x,t)\in [0,l]\times \mathbb{R}, 0 < p, q \in C^{\infty}([0,l]),$$ subject to some initial data and linear boundary conditions (see in Proposition 1 below). This time the main restrictions are some Diophantine conditions and asymptotic properties of the eigenfrequencies $\omega_n$ as $n \to \infty$. Some other results without these restrictions are also presented

Az önköltségszámítás, mint hatékony vezetéstámogató eszköz a költségvetési szektorban = Cost calculation as an efficient management decision making tool in the public sector

The main objective of this study is to draw the reader's attention to the fact that cost calculation can be regarded as an efficient management decision making tool in the public sector too. The new provisions of the Hungarian Accounting Act that took effect on 1st January 2014 applying to all business associations were a huge step towards the creation of a more standardized accounting system in the public sector. As a result of the changes in the law the accounting information system for public finances has become more complex as the cash-based turnover method (cash accounting) was supplemented by financial accounting, functioning on the principle of actual realization. The authors suggest that using financial accounting in the public sector may contribute to a more accurate measurability of the performance of public services. This study seeks to provide answers for how changes in accounting regulations have affected the rules and processes of costaccounting in the public sector primarily by conducting secondary research and by relying on the authors' professional experience

Az önköltségszámítás, mint hatékony vezetéstámogató eszköz a költségvetési szektorban = Cost calculation as an efficient management decision making tool in the public sector

The main objective of this study is to draw the reader's attention to the fact that cost calculation can be regarded as an efficient management decision making tool in the public sector too. The new provisions of the Hungarian Accounting Act that took effect on 1st January 2014 applying to all business associations were a huge step towards the creation of a more standardized accounting system in the public sector. As a result of the changes in the law the accounting information system for public finances has become more complex as the cash-based turnover method (cash accounting) was supplemented by financial accounting, functioning on the principle of actual realization. The authors suggest that using financial accounting in the public sector may contribute to a more accurate measurability of the performance of public services. This study seeks to provide answers for how changes in accounting regulations have affected the rules and processes of costaccounting in the public sector primarily by conducting secondary research and by relying on the authors' professional experience

Interaction of basin-scale topography- and salinity-driven groundwater flow in synthetic and real hydrogeological systems

Salinization of groundwater has endangered e.g. drinking water supply, agricultural cultivation, groundwater-dependent ecosystems, geothermal energy supply, thermal and hydrocarbon well production to a rising degree. In order to investigate the problem of coupled topography- and salinity-driven groundwater flow on a basin-scale, a systematic simulation set has been carried out in a synthetic numerical model. Detailed sensitivity analysis was completed to reveal the effect of the salinity, permeability, permeability heterogeneity and anisotropy, mechanical dispersivity and water table head on the salt concentration field and the flow pattern. It was established that a saline dome with slow inner convection formed beneath the discharge zone in the base model due to the topography-driven regional fresh groundwater flow. An increase in the salinity or the anisotropy or decrease in the water table variation weakens the role of the forced convection driven by the topography, thus facilitating the formation of a saline, dense, sluggish layer in the deepest zone of the basin. In the studied parameter range, the variation in permeability and dispersivity affects the shape of the saltwater dome to less degree. However, the decrease in permeability and/or the increase in dispersivity advantage the homogenization of the salt concentration within the saline zone and strengthen the coupling between the saltwater and freshwater zone by growing the relative role of diffusion and transverse dispersion, respectively. The interaction of the topography-driven forced and salinity driven free convection was investigated along a real hydrological section in Hungary. Simulation elucidated the fresh, brackish and saline character of the water sampled the different hydrostratigraphic units by revealing the connection between the topography-driven upper siliciclastic aquifer and the lower confined karstic aquifer through faults in high-salinity clayey aquitard. The current study improves the understanding of the interaction between the topography-driven forced and the salinity-driven free convection, i.e. topohaline convection, especially in basin-scale groundwater flow systems

Disruption of vascular Ca2+-activated chloride currents lowers blood pressure

High blood pressure is the leading risk factor for death worldwide. One of the hallmarks is a rise of peripheral vascular resistance, which largely depends on arteriole tone. Ca2+-activated chloride currents (CaCCs) in vascular smooth muscle cells (VSMCs) are candidates for increasing vascular contractility. We analyzed the vascular tree and identified substantial CaCCs in VSMCs of the aorta and carotid arteries. CaCCs were small or absent in VSMCs of medium-sized vessels such as mesenteric arteries and larger retinal arterioles. In small vessels of the retina, brain, and skeletal muscle, where contractile intermediate cells or pericytes gradually replace VSMCs, CaCCs were particularly large. Targeted disruption of the calcium-activated chloride channel TMEM16A, also known as ANO1, in VSMCs, intermediate cells, and pericytes eliminated CaCCs in all vessels studied. Mice lacking vascular TMEM16A had lower systemic blood pressure and a decreased hypertensive response following vasoconstrictor treatment. There was no difference in contractility of medium-sized mesenteric arteries; however, responsiveness of the aorta and small retinal arterioles to the vasoconstriction-inducing drug U46619 was reduced. TMEM16A also was required for peripheral blood vessel contractility, as the response to U46619 was attenuated in isolated perfused hind limbs from mutant mice. Out data suggest that TMEM16A plays a general role in arteriolar and capillary blood flow and is a promising target for the treatment of hypertension

Functional shift with maintained regenerative potential following portal vein ligation

Selective portal vein ligation (PVL) allows the two-stage surgical resection of primarily unresectable liver tumours by generating the atrophy and hypertrophy of portally ligated (LL) and non-ligated lobes (NLL), respectively. To evaluate critically important underlying functional alterations, present study characterised in vitro and vivo liver function in male Wistar rats (n = 106; 210-250 g) before, and 24/48/72/168/336 h after PVL. Lobe weights and volumes by magnetic resonance imaging confirmed the atrophy-hypertrophy complex. Proper expression and localization of key liver transporters (Ntcp, Bsep) and tight junction protein ZO-1 in isolated hepatocytes demonstrated constantly present viable and well-polarised cells in both lobes. In vitro taurocholate and bilirubin transport, as well as in vivo immunohistochemical Ntcp and Mrp2 expressions were bilaterally temporarily diminished, whereas LL and NLL structural acinar changes were divergent. In vivo bile and bilirubin-glucuronide excretion mirrored macroscopic changes, whereas serum bilirubin levels remained unaffected. In vivo functional imaging (indocyanine-green clearance test; (99mTc)-mebrofenin hepatobiliary scintigraphy; confocal laser endomicroscopy) indicated transitionally reduced global liver uptake and -excretion. While LL functional involution was permanent, NLL uptake and excretory functions recovered excessively. Following PVL, functioning cells remain even in LL. Despite extensive bilateral morpho-functional changes, NLL functional increment restores temporary declined transport functions, emphasising liver functional assessment

Levosimendan Administration in Limb Ischemia: Multicomponent Signaling Serving Kidney Protection

AIMS AND OBJECTIVES: Acute renal failure is a severe complication of lower extremity major arterial reconstructions, which could even be fatal. Levosimendan is a dual-acting positive inotropic and vasodilatory agent, which is suspected to have protective effects against cardiac ischemia. However, there is no data available on lower limb or remote organ ischemic injuries therefore the aim of the study was to investigate the effect of levosimendan on lower limb ischemia-reperfusion injury and the corollary renal dysfunction. METHODS: Male Wistar rats underwent 180 min bilateral lower limb ischemia followed by 4 or 24 hours of reperfusion. Intravenous Levosimendan was administered continuously (0.2mug/bwkg/min) throughout the whole course of ischemia and the first 3h of reperfusion. Results were compared with sham-operated and ischemia-reperfusion groups. Hemodynamic monitoring was performed by invasive arterial blood pressure measurement. Kidney and lower limb muscle microcirculation was registered by a laser Doppler flowmeter. After 4h and 24h of reperfusion, serum, urine and histological samples were collected. RESULTS: Systemic hemodynamic parameters and microcirculation of kidney and the lower limb significantly improved in the Levosimendan treated group. Muscle viability was significantly preserved 4 and 24 hours after reperfusion. At the same time, renal functional laboratory tests and kidney histology demonstrated significantly less expressive kidney injury in Levosimendan groups. TNF-alpha levels were significantly less elevated in the Levosimendan group 4 hours after reperfusion. CONCLUSION: The results claim a protective role for Levosimendan administration during major vascular surgeries to prevent renal complications

Demonstration of Metabolic and Cellular Effects of Portal Vein Ligation Using Multi-Modal PET/MRI Measurements in Healthy Rat Liver.

OBJECTIVES: In the early recognition of portal vein ligation (PVL) induced tumor progression, positron emission tomography and magnetic resonance imaging (PET/MRI) could improve diagnostic accuracy of conventionally used methods. It is unknown how PVL affects metabolic patterns of tumor free hepatic tissues. The aim of this preliminary study is to evaluate the effect of PVL on glucose metabolism, using PET/MRI imaging in healthy rat liver. MATERIALS AND METHODS: Male Wistar rats (n = 30) underwent PVL. 2-deoxy-2-(18F)fluoro-D-glucose (FDG) PET/MRI imaging (nanoScan PET/MRI) and morphological/histological examination were performed before (Day 0) and 1, 2, 3, and 7 days after PVL. Dynamic PET data were collected and the standardized uptake values (SUV) for ligated and non-ligated liver lobes were calculated in relation to cardiac left ventricle (SUVVOI/SUVCLV) and mean liver SUV (SUVVOI/SUVLiver). RESULTS: PVL induced atrophy of ligated lobes, while non-ligated liver tissue showed compensatory hypertrophy. Dynamic PET scan revealed altered FDG kinetics in both ligated and non-ligated liver lobes. SUVVOI/SUVCLV significantly increased in both groups of lobes, with a maximal value at the 2nd postoperative day and returned near to the baseline 7 days after the ligation. After PVL, ligated liver lobes showed significantly higher tracer uptake compared to the non-ligated lobes (significantly higher SUVVOI/SUVLiver values were observed at postoperative day 1, 2 and 3). The homogenous tracer biodistribution observed before PVL reappeared by 7th postoperative day. CONCLUSION: The observed alterations in FDG uptake dynamics should be taken into account during the assessment of PET data until the PVL induced atrophic and regenerative processes are completed