Using longitudinal survival probabilities to test field vigour estimates in sugar maple (Acer saccharum Marsh.)

Tree mortality is a major force driving forest dynamics. To foresters, however, tree mortality is often considered a loss in productivity. To reduce tree mortality, silvicultural systems, such as selection cuts, aim at removing trees that are more likely to die. In order to identify trees with higher risks of mortality, field classifications are employed that assess vigour based on external characteristics of trees. We used a novel longitudinal approach for estimating survival probabilities based on ring-width measurements, initially developed by Bigler and Bugmann [Bigler, C., Bugmann, H., 2004. Predicting the time of tree death using dendrochronological data. Ecol. Appl. 14 (3), 902-914], to parameterize a survival probability model for sugar maple (Acer saccharum Marsh.) and to test whether field-assessed tree vigour classes are corroborated by survival probabilities determined from radial growth history. Data from 56 dead and 321 live sugar maples were collected in stands in western Quebec (Canada) that had undergone a selection cut ≈10 years prior to sampling. Our results showed that tree vigour established from external defects and pathological symptoms, using the classification of Boulet [Boulet, B., 2005. D

Pulse-shape discrimination with PbWO4_4 crystal scintillators

The light output, $\alpha/\beta$ ratio, and pulse shape have been investigated at $-25^\circ$ C with PbWO$_4$ crystal scintillators undoped, and doped by F, Eu, Mo, Gd and S. The fast $0.01-0.06 \mu$s and middle $0.1-0.5 \mu$s components of scintillation decay were observed for all the samples. Slow components of scintillation signal with the decay times $1-3 \mu$s and $13-28 \mu$s with the total intensity up to $\approx50$ have been recognized for several samples doped by Molybdenum. We found some indications of a pulse-shape discrimination between $\alpha$ particles and $\gamma$ quanta with PbWO$_4$ (Mo doped) crystal scintillators.Comment: 12 pages, 5 figures, submitted to NIM

Foreign direct investment and investment environment in Dongguan Municipality of southern China

Based on 26 case studies, this paper investigates the socio-economic causes of the inflow of FDI and its policy implications in Dongguan. The favourable factors for foreign investors in Dongguan can be categorised under the Dunning's OLI (ownership, locational and internalisation advantages) framework. This paper argues that factors other than policy incentive, such as sub-contractual and pseudo integration, are playing more important roles in attracting the inflow of FDI and maintaining the high level of economic growth in Dongguan. This finding questions the effectiveness of policy incentives, such as tax-breaks, implemented by the Government as a means to attract FDI in Dongguan. The existence of 'Chinese crony capitalism' calls for further improvement in the implementation of laws and regulations in Dongguan and the reduction of bureaucratic red-tape by the central and local governments

The Impact of Revascularization in a Patient with Atypical Manifestations of Hypoperfusion

Publisher Copyright: © 2022 by the authors.Background and Objectives: Carotid revascularization is one of the most effective treatment options in patients with severe carotid artery stenosis causing hypoperfusion in basal ganglia. Atypical manifestations include hyperkinetic movements, noted as extremely rare. We report a case about a patient with 2-months-long complaints of Uncontrollable movements in his right side of the body subsided after carotid revascularization. Case presentation: A 71-year-old male was admitted to Pauls Stradins Clinical University Hospital with the main complaints of 2-months-long uncontrollable movements in his right hand and his right leg. When performing coordination tasks, slight inaccuracy was noted with the right-side extremities. Hyperkinetic movements—choreoathetosis in the right side of the patient’s face, arm, and leg—were seen. Computed tomography angiography revealed subocclusion in the proximal segment of the left internal carotid artery and 30% stenosis in the proximal segment of the right internal carotid artery. The patient was consulted by a vascular surgeon. Eversion endarterectomy of the left internal carotid artery was performed. The early postoperative period occurred without complications. The patient was discharged from the hospital 2 days after the surgery in good overall health condition. Two months later, choreoathetotic movements in his right side of the body had markedly decreased. No focal neurologic deficits were noted. Conclusions: Revascularization may be effective by eliminating emboli and stenosis, leading to hypoperfusion in watershed territories. A case of a 71-year-old male patient with the main complaints of 2-months-long uncontrollable movements in his right side of the body subsiding after carotid revascularization was demonstrated. It is vital to recognize atypical manifestations of hypoperfusion, associated with stenosis in internal carotid arteries, to early make a diagnosis, to perform an appropriate treatment, and to reduce the risk of cerebral infarction in the future, resulting in a longer high-quality life for the patient.publishersversionPeer reviewe

Tunneling luminescence in long lasting afterglow of SrAl2O4:Eu,Dy

The publication is prepared with the financial support of National Research Programme IMIS2.A long lasting (afterglowing) luminescent material SrAl2O4: Eu2+, Dy3+ was prepared by high temperature solid-state reaction method. The processes responsible for long lasting luminescence were studied by means of luminescence spectra, thermally stimulated luminescence and afterglow kinetics. Two processes are found to contribute in excited Eu 2+ creation – the thermally released electrons recombination and electron tunneling from trap to Eu3+. The possible scheme of long lasting luminescence mechanism is proposed.IMIS2; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART

Fatigue and associated factors in multiple sclerosis patients in Latvia

Sum mary. Back ground and ob jec tives. Fa tigue is one of the most com mon symp toms of mul ti ple scle ro sis (MS). The aim of this study was to de ter mine the pres ence of fa tigue in MS pa tients in Lat via and its re la tion to life style fac tors, neu ro log i cal dis abil ity and de pres sion. Ma te rial and meth ods. This cross-sec tional study in cluded 117 par tic i pants (44 pa tients with MS and 73 healthy con trol group). Ap plied re search in stru ments were: Ex panded Dis - abil ity Sta tus Scale (EDSS), Pa tient Health Ques tion naire (PHQ-9), Fa tigue Se ver ity Scale (FSS), and the gen eral ques tion naire for the col lec tion of socio-de mo graphic, life style hab its and clin i cal data con structed for the pur poses of this study. Re sults. Mean FSS score was 3.9±1.9 in MS group. 26 (59.1%) patients had FSS score of 3.8 or more and were clas si fied as a fa tigue group (MSF) while 18 (40.9%) patients had FSS of 3.7 or less and were clas si fied as a non-fatigue (MSNF) group. There was sta tis ti cally sig - nif i cant dif fer ence be tween MSF and MSNF groups con sid er ing PHQ-9 score (p=0.019), FSS score (p<0.001) and EDSS score (p<0.001). Sig nif i cant cor re la tions of fa tigue with depres sion (r=0.48, p=0.001), fa tigue with neu ro log i cal dis abil ity (r=0.49, p=0.001) and fatigue with smok ing (r=0.29, p=0.054) were con firmed. Con clu sions. Fa tigue is a com mon symptom in MS pa tients in Lat via. This study supports sig nif i cant as so ci a tion be tween fa tigue and clin i cal fac tors (dis abil ity, de pres sion) and mod i fi able life style fac tor – smok ingpublishersversionPeer reviewe

Delayed Spinal Arachnoiditis with Syringomyelia Following Aneurysmal Subarachnoid Haemorrhage : A Case Report with Patient Experience

Publisher Copyright: © The Author(s) 2024.Background and importance Syringomyelia or the formation of fluid-filled cysts within the spinal cord associated with delayed spinal arachnoiditis is an uncommon complication of aneurysmal subarachnoid haemorrhage. To date, about 18 cases have been reported in medical literature, with just two reported in patients under the age of 35 years. Clinical presentation A 27-year-old female patient complained of sudden, severe headaches in the occipital region, nuchal rigidity, and drowsiness when she presented at our institution. A head computed tomography scan revealed intraventricular bleeding in the lateral and fourth ventricles with more extensive haemorrhaging in the frontal horns. A left posterior inferior cerebellar artery (PICA) aneurysm was confirmed via digital subtraction angiogram, and endovascular embolization was done. Two years later, the patient reported intense pain in the lower back along with symptoms suggestive of spinal cord compression. Spinal magnetic resonance imaging (MRI) showed spinal adhesions from C1 to L4, syringomyelia with some vasogenic oedema extending from T3 to T9 level, and a cyst in the lumbar region. Consequently, a right hemilaminectomy was performed along with microsurgical release of arachnoid adhesions and placement of a subdural drain. Radiological and symptomatic improvements were observed. Since then, the patient's clinical condition has remained stable during the past three years of follow-up visits. Conclusions Literature on optimal treatment modalities and patient prognosis is scarce and debated. The time for symptom improvement depends on the level and extent of spinal cord involvement. Rehabilitation may be required for most patients, as complete symptomatic recovery may not be attainable.Peer reviewe

History of Academic Neurology in Latvia

Peer reviewe

Functional and Structural Evaluation of Afferent Visual System in Multiple Sclerosis Patients

Publisher Copyright: © 2015 by Daina Pastare.There is insufficient information about the progress and variability of multiple sclerosis (MS). Afferent visual pathways are an appropriate MS clinical model. Optical coherence tomography (OCT) allows to perform precise measurements of axonal tissue in the retinal nerve fibre layer (RNFL). Visual evoked potentials (VEP) provide information about the functional status of visual pathways. The aim of our study was to use OCT and VEP to evaluate MS patients with and without optic neuritis (ON) history and to determine relationships between functional and structural changes. The cross-sectional study included 76 relapsing-remitting MS patients and 28 healthy controls. The lowest mean VEP N75/P100 amplitude was found in ON affected eyes (8.16 mkV, SD = 4.60). However, it was observed that the mean amplitude in patients without ON (M = 9.86; SD = 4.63) was by 4.64 mkV lower than in controls (p 0.001) between RNFLT and mean P100 latency. In summary, we found that deterioration in the visual system was not associated with the clinical ON episode. Regardless of ON symptoms in history, there exists correlation between functional and structural changes.publishersversionPeer reviewe

The search for defects in undoped SrAl2O4 material

This research project was supported financially by ERDF Project No: Nr.1.1.1.1/16/A/182 .SrAl2O4:Eu,Dy is a very efficient long afterglow phosphor with wide range of possible applications. The luminescence properties and the possible luminescence mechanism of this material have been studied extensively, but there is almost no information available about the undoped material. Therefore, this article deals with the luminescence and thermally stimulated luminescence of an undoped SrAl2O4, revealing the possible defects that might be involved in the creation of the long afterglow in doped material. We conclude that undoped material exhibits some luminescence under X-ray irradiation in low temperature; close to room temperatures luminescence is almost fully thermally quenched in comparison to low temperatures. We can observe F and F2 center luminescence as well as trace metal luminescence in the emission spectrum. TSL glow curve yields the peaks that are close to those observed in material with Eu and Dy doping; therefore these peaks are clearly related to intrinsic defects. The peak at around 400 K, that is shifting with rare earth doping, might be due to dopant interaction with intrinsic defects.European Regional Development Fund Nr.1.1.1.1/16/A/182; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART