On eigenvalues of the Schr\"odinger operator with an even complex-valued polynomial potential

In this paper, we generalize several results of the article "Analytic continuation of eigenvalues of a quartic oscillator" of A. Eremenko and A. Gabrielov. We consider a family of eigenvalue problems for a Schr\"odinger equation with even polynomial potentials of arbitrary degree d with complex coefficients, and k<(d+2)/2 boundary conditions. We show that the spectral determinant in this case consists of two components, containing even and odd eigenvalues respectively. In the case with k=(d+2)/2 boundary conditions, we show that the corresponding parameter space consists of infinitely many connected components

Petogodišnja studija ispitivanja funkcije pluća i izloženost formaldehidu u drvnoj industriji

In an earlier cross-sectional study 47 formaldehyde glueing workers and 20 non-exposed control subjects were examined. In a follow-up study, five years later, 13 subjects had been transferred to other jobs whereas 21 were still occupationally exposed to formaldehyde. The results indicate a slow progress of lung function impairment in excess of the one due to normal ageing, at an average exposure to formaldehyde of 0.4 - 0.5 mg/m3 of air. The progress was significant for the FEV75-25 variables. These values returned to normal among non-smokers during a four-week vacation but remained unchanged among the smokers. A dose-effect relationship was found between exposure to formaldehyde and decrease in lung function among smokers.U prethodnoj studiji ispitivano je 47 osoba koje su bile izložene ljepilu s formaldehidom i 20 osoba koje su poslužile kao kontrola. Pet godina kasnije ponovno su ispitivani isti radnici, što je opisano u ovoj studiji. Od početne grupe 13 radnika bilo je premješteno na druge poslove, dok je 21 radnik još uvijek bio profesionalno izložen formaldehidu. Rezultati upućuju na polagano smanjenje plućnih funkcija koje je veće od uobičajenih posljedica starenja, pri ekspoziciji formaldehidu od 0,4 do 0,5 mg/ml3 zraka. Proces je statistički značajan za varijablu FEV75-25, a reverzibilan je u nepušača za vrijeme 4-tjednog godišnjeg odmora, za razliku od pušača u kojih je ireverzibilan. U pušača je nađena povezanost smanjenja plućnih funkcija ovisna o izloženosti formaldehidu

Longitudinalno ispitivanje rizika respiratornih oštećenja pri izloženosti terpenima u pilanama

Forty-eight subjects exposed to terpenes (mean exposure: 254 mg/m3) in two saw-mills in northern Sweden and 46 local controls were examined in a two-year follow-up study. Symptoms for the upper airways were significantly more common in the exposed group than among the controls. The FVC and FEV1 variables were reduced by an average of 0.32 and 0.47 L, respectively, compared to normal values. The nitrogen washout variables also differed between the exposed and controls with raised values in CV% and in the slope of the alveolar plateau (phase III), indicating an obstructive lung function impairment. A day of industrial exposure (Monday) caused no further decrease in any of the lung function variables. After improved environmental control the exposure to terpenes decreased to about 150-200 mg/m3. A new examination of the same subjects was performed two years later. In the follow-up study the mean FVC values were unchanged compared to normal values. However, the mean difference between the exposed and control workers was reduced by more than 50% in the variable FEV1.o and phase III. No further reduction was recorded after four weeks of no exposure (holiday).U dvogodišnjoj studiji ispitivano je 48 osoba izloženih terpenima u dvije pilane sjeverne Švedske (pri čemu je srednja ekspozicija bila 254 mg/m3), kao i 46 osoba iz istog poduzeća koje su poslužile kao kontrolna skupina. Simptomi gornjega respiratornog trakta bili su značajno učestaliji u izloženoj skupini u odnosu na kontrolu. FVK i FEV1 bili su smanjeni u prosjeku 0,32, odnosno 0,47 L usporedbi s normalnim vrijednostima. Vrijednosti dobivene testiranjem dušikom razliko¬vale su se u izloženih osoba u odnosu na kontrolnu skupinu u smislu povišenja KV%, kao i u na¬gibu alveolarnog platoa, upućuju na opstruktivno oštećenje pluća. Nakon ponovnog izlaganja ovim spojevima (ponedjeljkom), nije primijećene smanjivanje bilo koje od varijabli plućnih funkcija. Nakon poboljšanja uvjeta rada izloženost terpenima se smanjila te je ekspozicija iznosila 150-200 mg/m3. Isti ispitanici ponovno su pregledani nakon dvije godine te je nađeno da se FVK ne razlikuje od normalne vrijednosti. Usto je nađena da su vrijednosti FEV1 i nagib alveolarnog platoa u izloženih radnika smanjeni za više od 50% u usporedbi s kontrolnim radnicima. Nije primijećene daljnje smanjenje ovih vrijednosti nakon četiri tjedna prestanka izloženosti

Kontrola, tehnologija i mehanizam djelovanja izloženosti prašini i plinovima na plućnu funkciju

In an earlier investigation, a major temporary effect on the lung function was determined, with a spirometer, in stevedoors on a ro-ro-ship exposed to diesel exhausts from trucks during a work shift. In the present study all the trucks used aboard were equipped with especially designed micro-filters mounted on the exhaust pipes. When the filter was in use, no significant effect on the lung function was measured. The removal of the particulate fraction of the exhausts by filtering modified, or possibly eliminated, the effect observed earlier. In designing an indicator of the biological effects of diesel exhausts the particle fraction should be taken into consideration.U prijašnjem istraživanju nađen je značajan prolazni učinak ispušnih plinova kamiona na plućnu funkciju radnika za vrijeme smjene. U sadašnjem istraživanju svi kamioni imali su specijalne mikro filtre pričvršćene na ispušne cijevi. Pri upotrebi filtara nije primijećeno značajno djelovanje ispušnih plinova na plućnu funkciju. Uklanjanje određenog dijela plinova promijenilo je ili sasvim eliminiralo djelovanje koje je prije primijećeno. Stoga bi pri stvaranju indikatora za biološko djelovanje osobitu pažnju trebalo obratiti na tu frakciju ispušnih plinova dizel-goriva

Profesionalna izloženost, plućna funkcija i antitijela na Rhizopus u radnika u pilanama

Sixty-six wood trimmers and local control subjects were examined several times in a 27-month follow-up study. FVC and FEV1 were reduced by an average of 0.4 and 0.3 L, respectively, after a month of no exposure. Repeated measurements three months later, on a Monday before work, showed a further reduction in PVC and FEY1 by an average of 0.21 L in a saw-mill with a high exposure to moulds (5 x 10 4 colony-forming units/m3), but not in another saw-mill with a 10 times lower exposure. Further recordings 27 months later, on a Monday before work, displayed no further reduction in any spirometric variable. No change in lung function was noted after one day of work (Monday), but a further reduction in FVC of an average of 0.3 L was seen in non-smokers at the end of the week, with apparent resolution over the weekend. The impairment was more obvious at the saw-mill with the higher air concentrations of organic dust than at the other saw-mill. It is concluded that wood trimmers may develop a restrictive pulmonary dysfunction, which might be explained by an immunopathological reaction to heavy mould exposureU 27-mjesečnoj studiji višekratno je ispitivano 66 radnika zaposlenih u dvije pilane sjeverne Švedske i lokalnih kontrola. Smanjenje vrijednosti FVC i FEV1 nađeno je u radnika nakon mjesec dana odmora, i to za 0,4 odnosno 0,3 L. Ponovljeno mjerenje nakon tri mjeseca, a prije početka rada, pokazalo je daljnju redukciju ovih vrijednosti, i to u prosjeku za 0,21 L u radnika pilana s visokom izloženošću plijesnima (5 x 10 4 kolonija), što nije primijećeno u drugoj pilani s 10 puta manjom koncentracijom plijesni. Pri opetovanom ispitivanju nakon 27 mjeseci, u ponedjeljak, i to prije početka i nakon završetka radne smjene, nije došlo do daljnjeg smanjenja spirometrijskih varijabli. Međutim, daljnje smanjenje FVC-a (u prosjeku 0,3 L) primijećeno je krajem tjedna, i to u nepušača, s prividnim poboljšanjem tijekom vikenda. Smanjenje plućnih funkcija bilo je uočljivije u pilani s većom koncentracijom organskih prašina. Zaključuje se da se u radnika u pilanama mogu razviti restriktivne promjene plućne funkcije, koje se mogu objasniti kao imunopatološka reakcija na veliko zagađenje plijesnima

Utjecaj izloženosti 1,6-heksametilen diizocijanatu (HDI) na vršni ekspiratorni protok u autolakirera u Iranu

The aim of this study was to investigate the effects of occupational exposure to 1,6-hexamethylene diisocyanate (HDI) on peak flowmetry in automobile body paint shop workers in Iran. We studied a population of 43 car painters exposed to HDI at their workplaces. Peak expiratory fl ow was tested for one working week, from the start to the end of each shift. Air was sampled and HDI analysed in parallel, according to the OSHA 42 method. Daily and weekly HDI exposure averages were (0.42±0.1) mg m-3 and (0.13±0.05) mg m-3, respectively. On painting days, 72 % of workers showed more than a 10 % variation in peak expiratory fl ow. Inhalation exposure exceeded the threshold limit value (TLV) ten times over. This strongly suggests that HDI affected the peak fl owmetry in the studied workers.Cilj je ovog ispitivanja bio utvrditi vršni protok u 43 iranska autolakirera profesionalno izložena 1,6-heksametilen diizocijanatu (HDI). Vršni ekspiratorni protok testiran je tjedan dana na početku i kraju svake smjene. Uzorkovanje i mjerenje HDI-ja u zraku radilo se istodobno s testiranjem vršnoga protoka, prema metodi OSHA 42. Prosječna dnevna izloženost radnika HDI-ju iznosila je (0.42±0.1) mg m-3, a tjedna (0.13±0.05) mg m-3. U 72 % radnika vršni ekspiratorni protok tijekom dana varirao je više od 10 %. Radnici su udisali deset puta više razine HDI-ja od graničnih te je moguće da je HDI utjecao na mjerenja plućne funkcije

Limpet Shells from the Aterian Level 8 of El Harhoura 2 Cave (Témara, Morocco): Preservation State of Crossed-Foliated Layers

International audienceThe exploitation of mollusks by the first anatomically modern humans is a central question for archaeologists. This paper focuses on level 8 (dated around * 100 ka BP) of El Har-houra 2 Cave, located along the coastline in the Rabat-Témara region (Morocco). The large quantity of Patella sp. shells found in this level highlights questions regarding their origin and preservation. This study presents an estimation of the preservation status of these shells. We focus here on the diagenetic evolution of both the microstructural patterns and organic components of crossed-foliated shell layers, in order to assess the viability of further investigations based on shell layer minor elements, isotopic or biochemical compositions. The results show that the shells seem to be well conserved, with microstructural patterns preserved down to sub-micrometric scales, and that some organic components are still present in situ. But faint taphonomic degradations affecting both mineral and organic components are nonetheless evidenced, such as the disappearance of organic envelopes surrounding crossed-foliated lamellae, combined with a partial recrystallization of the lamellae. Our results provide a solid case-study of the early stages of the diagenetic evolution of crossed-foliated shell layers. Moreover, they highlight the fact that extreme caution must be taken before using fossil shells for palaeoenvironmental or geochronological reconstructions. Without thorough investigation, the alteration patterns illustrated here would easily have gone unnoticed. However, these degradations are liable to bias any proxy based on the elemental, isotopic or biochemical composition of the shells. This study also provides significant data concerning human subsistence behavior: the presence of notches and the good preservation state of limpet shells (no dissolution/recrystallization, no bioerosion and no abrasion/fragmentation aspects) would attest that limpets were gathered alive with tools by Middle Palaeolithic (Aterian) populations in North Africa for consumption

Bilateral hip exoskeleton assistance enables faster walking in individuals with chronic stroke-related gait impairments

Millions of individuals surviving a stroke have lifelong gait impairments that reduce their personal independence and quality of life. Reduced walking speed is one of the major problems limiting community mobility and reintegration. Previous studies have shown positive effect of robot-assisted gait training utilizing hip exoskeletons for individuals with gait impairments due to a stroke, leading to increased walking speed in post-treatment compared to pre-treatment assessments. However, no evidence emerged of a significant increasing in walking speed attributable to device usage compared to walking without the device. In this pilot investigation, we observed that hip flexion/extension assistance delivered by a portable bilateral powered hip exoskeleton increased overground self-selected walking speed by 20.2 ± 5.0% on average among six chronic post-stroke survivors. When comparing walking with and without the hip exoskeleton within the same experimental session, the observed speed increment resulted in statistically and clinically meaningful improvement (0.14 ± 0.03&nbsp;m/s &gt; minimal clinically important difference, p = 0.015). The increased walking speed was the result of a higher self-selected cadence and longer step length both on the paretic and nonparetic limbs. By facilitating gait, a bilateral hip exoskeleton could be a viable technology for extending locomotor mobility and facilitating gait training of individuals affected by post-stroke hemiparesis

An impairment-specific hip exoskeleton assistance for gait training in subjects with acquired brain injury: a feasibility study

This study was designed to investigate the feasibility and the potential effects on walking performance of a short gait training with a novel impairment-specific hip assistance (iHA) through a bilateral active pelvis orthosis (APO) in patients with acquired brain injury (ABI). Fourteen subjects capable of independent gait and exhibiting mild-to-moderate gait deficits, due to an ABI, were enrolled. Subjects presenting deficit in hip flexion and/or extension were included and divided into two groups based on the presence (group A, n = 6) or absence (group B, n = 8) of knee hyperextension during stance phase of walking. Two iHA-based profiles were developed for the groups. The protocol included two overground gait training sessions using APO, and two evaluation sessions, pre and post training. Primary outcomes were pre vs. post-training walking distance and steady-state speed in the 6-min walking test. Secondary outcomes were self-selected speed, joint kinematics and kinetics, gait symmetry and forward propulsion, assessed through 3D gait analysis. Following the training, study participants significantly increased the walked distance and average steady-state speed in the 6-min walking tests, both when walking with and without the APO. The increased walked distance surpassed the minimal clinically important difference for groups A and B, (respectively, 42 and 57&nbsp;m &gt; 34&nbsp;m). In group A, five out of six subjects had decreased knee hyperextension at the post-training session (on average the peak of the knee extension angle was reduced by 36%). Knee flexion during swing phase increased, by 16% and 31%, for A and B groups respectively. Two-day gait training with APO providing iHA was effective and safe in improving walking performance and knee kinematics in ABI survivors. These preliminary findings suggest that this strategy may be viable for subject-specific post-ABI gait rehabilitation