Modularity of Convergence and Strong Convergence in Infinitary Rewriting

Properties of Term Rewriting Systems are called modular iff they are preserved under (and reflected by) disjoint union, i.e. when combining two Term Rewriting Systems with disjoint signatures. Convergence is the property of Infinitary Term Rewriting Systems that all reduction sequences converge to a limit. Strong Convergence requires in addition that redex positions in a reduction sequence move arbitrarily deep. In this paper it is shown that both Convergence and Strong Convergence are modular properties of non-collapsing Infinitary Term Rewriting Systems, provided (for convergence) that the term metrics are granular. This generalises known modularity results beyond metric \infty

Femtosecond-pulse-train ionization of Rydberg wave packets

We calculate, based on first-order perturbation theory, the total and differential ionization probabilities from a dynamic periodic Rydberg wave packet of a given n-shell exposed to a train of femtosecond laser pulses. The total probability is shown to depend crucially on the laser repetition rate: For certain frequencies the ionization probability vanishes, while for others it becomes very large. The origin of this effect is the strong dependence of the ionization probability on the Stark quantum number. Correspondingly, the angular electronic distribution also changes significantly with the increasing number of pulses for certain repetition rates.publishedVersio

Överbyggnad - utformning vid beläggning av natursten och markbetong

Förstå! Gör rätt! Spara hundratals miljoner kronor för ägare av urbana ytor! Så lyder vårt huvudbudskap i detta Movium Fakta, som på ett kortfattat och elementärt sätt behandlar överbyggnad med beläggning av natursten och markbetong i stadsliknande miljöer

Överbyggnad med beläggning av natursten och markbetong, för trafikklass ≤ 2 : förenklad dimensionering för stadsliknande miljöer

Feldimensionerad överbyggnad, felaktiga material, fel kombination av material och felaktigt utförande kommer att, med tiden, visa sig som spårbildningar, ojämnheter, sättningar, tjällyftningar, osv på ytan av markbeläggningen. I bästa fall visar sig skadorna tidigt under garantitiden då det fortfarande finns en affärsrelation mellan entreprenör, konstruktör och byggherre/beställare, och då det fortfarande finns en möjlighet till att utreda och åtgärda. I värsta fall är skadeförloppet långsamt och visar sig på ytan lång tid efter garantibesiktning dåbeställaren sitter ensam med problemet med en anläggning som sedan länge tagits i bruk. Det drabbar då i första hand driftsavdelningen och i detta läge kommer alla berörda parter att kräva snabba åtgärder vilket vanligen medför kosmetiska justeringar på ytan. Eftersom synliga skador i ytan normalt endast är ett symptom på ett skadeförlopp väl dolt längre ned i överbyggnaden uppnår man endast en tillfällig förbättring, med ständigt återkommande problem med ytan. Med tiden kommer acceptansnivån för ytskadorna att öka och kvar finns då kanske en högbudgetinvestering i lågbudgetutförande, med höga driftskostnader som följd

Egg distribution, bottom topography and small-scale cod population structure in a coastal marine system

Coastal marine species with pelagic egg and larval stages, such as the Atlantic cod Gadus morhua, can be structured into genetically distinct local populations on a surprisingly small geographic scale considering their dispersal potential. Mechanisms responsible for such small-scale genetic structure may involve homing of adults to their natal spawning grounds, but also local retention of pelagic eggs and larvae. For example, spawning within sheltered fjord habitats is expected to favour local retention of early life stages. Here, we studied the distribution of cod eggs along inshore-offshore transects in 20 Norwegian fjords. The general pattern exhibited across all fjords was a higher concentration of cod eggs inside the fjords than further offshore. In particular, fjords with shallow sills (model threshold 37 m) show an abrupt reduction in egg density over the sill. This study provides empirical support for an offspring retention hypothesis, which may help to explain the maintenance of local population structure in pelagic marine systems

Carbon monoxide poisoning in Denmark with focus on mortality and factors contributing to mortality

IntroductionCarbon monoxide (CO) poisoning is frequent worldwide but knowledge regarding the epidemiology is insufficient. The aim of this study was to clarify the extent of this intoxication, its mortality and factors associated with mortality.Materials and methodsNational databases from Statistics Denmark were used to identify individuals who suffered from CO-poisoning during 1995-2015, as well as information regarding co-morbidities, mortality and manner of death.ResultsDuring the period from 1995 to 2015, 22,930 patients suffered from CO-poisoning in Denmark, and 21,138 of these patients (92%) were hospitalized. A total of 2,102 patients died within the first 30 days after poisoning (9.2%). Among these, 1,792 (85% of 2,102) were declared dead at the scene and 310 (15% of 2,102) died during hospitalization. Deaths due to CO-poisoning from smoke were intentional in 6.3% of cases, whereas deaths due to CO containing gases were intentional in 98.0% of cases. Among patients who survived >30 days, there was no significant difference in survival when comparing hyperbaric oxygen therapy (HBO) treatment with no HBO treatment after adjustment for age and co-morbidities such as drug abuse, psychiatric disease, stroke, alcohol abuse, arterial embolism, chronic obstructive pulmonary disease, cerebrovascular disease and atrial fibrillation. Several co-morbidities predicted poorer outcomes for patients who survived the initial 30 days.ConclusionsPoisoning from smoke and/or CO is a frequent incident in Denmark accounting for numerous contacts with hospitals and deaths. Both intoxication and mortality are highly associated with co-morbidities interfering with cognitive and physical function. Treatment with HBO was not seen to have an effect on survival