Innovative productivity improvements in forest operations: a comparative study of the Assortment Grapple using a machine simulator

Because of generally small log piles, loading forwarders during thinning is time consuming. The Assortment Grapple, an innovative grapple with an extra pair of claws which facilitates the handling of two assortments during one loading crane cycle, has been designed to decrease forwarders’ loading time consumption. A standardized experiment was performed in a virtual thinning stand using a machine simulator with the objectives to form guidelines for working with the Assortment Grapple and to analyse its development potential. Four experienced operators participated in the study. According to the results, the Assortment Grapple’s accumulating function is beneficial only when there are no remaining trees between piles loaded during the same crane cycle. In such cases, none of participating operators lost time, and 3 of 4 operators saved time notably. The problem with the remaining trees is the extra time required to steer the crane tip around them. Therefore, a harvester should place those log piles that are later to be forwarded together in the same space with no remaining trees between the piles. Furthermore, we recommend that the Assortment Grapple’s usability will be improved by adding an own rocker switch on the forwarder’s controls to command the extra claws

Declining survival rates of red foxes Vulpes vulpes during the first outbreak of sarcoptic mange in Sweden

Rapid declines in red fox Vulpes vulpes populations have followed outbreaks of epizootic mange caused by the mite Sarcoptes scabiei. In Sweden, the first outbreak of sarcoptic mange started in 1977/1978 and affected the whole country by 1984. Here we used data on the number of harvested red foxes (51 480) from Gävleborg county (18 199 km2) in Sweden between 1970 and 1994. We used data on the prevalence of sarcoptic mange in a sample of harvested red foxes (2694) from 1974 to 1982. A rapid decline in harvested foxes occurred two to three years after the prevalence of sarcoptic mange first became evident. In the same period, mark–recovery data were used to estimate changes in survival rates, and the best model included an effect of age (young or adult) and period (annual) on the survival and recapture probabilities. The analysis was based on data from 701 young foxes of which 523 were recovered, and 133 adults of which 131 were recovered. Average annual survival was 0.55 (range = 0.53–0.58) for adults and 0.36 (range = 0.32–0.39) for young foxes in the three years preceding the outbreak. During the outbreak and the remaining six years of the study, the average survival was reduced to 0.41 (range = 0.30–0.48) for adults and to 0.25 (range = 0.17–0.30) for young foxes. A population model, based on results on our survival analysis and literature data on fecundity, was developed to project the decline of the fox population. The rate and magnitude of the reduction in projected population and harvested foxes were similar, with both reduced by almost ninety percent. Harvest statistics indicate the fox population recovered to pre-mange densities in less than 10 years after the first detection of mange indicating a rapid development of resistance in the host. This study shows the importance of long-term population monitoring in combination with large-scale field-experiments to devise alternative management options.publishedVersio

Incentive pay-systems and its impact on motivation and goal congruence : a case study at Tele2 in Kista, Stockholm

Företagens prestation styrs i hög grad av medarbetarnas prestation vilket innebär att motiverade och tillfredsställda medarbetare är grunden för ett välmående företag. Belöningssystem är ett verktyg företag kan använda sig av då de vill motivera sina medarbetare till att arbeta mot önskad målsättning. Tidigare studier inom området visar däremot att det finns delade meningar angående hur resultatbaserade belöningssystem påverkar motivationen hos medarbetare. Organisationens målsättning kan stå i konflikt med medarbetarnas individuella målsättningar om dessa mål inte överensstämmer med varandra. En konsekvens av att det uppstår konflikter mellan organisationens mål och medarbetarnas individuella målsättningar är att det kan leda till en lägre grad av målkongruens vilket då innebär att medarbetare och organisation arbetar i olika riktningar. Tidigare studier har fokuserat på belöningssystem och motivation, men det finns relativt få undersökningar som kopplar dessa teorier till målkongruens. Syftet med denna uppsats är att öka förståelsen för vilka effekter ett belöningssystem har på medarbetarnas och organisationens målkongruens. Studien baseras på en kvalitativ fallstudie med induktiv ansats. Studien är avgränsad till att undersöka Tele2:s business to business-enhet i Kista, Stockholm. Den specifika avgränsningen gör att resultaten som visas i studien inte kan anses generaliserbara. Empiri för undersökningen har inhämtats från sex semistrukturerade intervjuer med chefer och medarbetare hos fallföretaget Tele2:s business to business-enhet i Kista, Stockholm. Urvalet var av icke-slumpmässig karaktär. Respondentgruppen bestod av både chefer och medarbetare för att få fler perspektiv på hur belöningssystem, motivation och målkongruens kan länkas samman. Det teoretiska kapitlet är utformat med fyra ämnesområden där relevanta teorier presenterats inom respektive område. Det teoretiska ramverk som användes för studien baseras på teorier kring belöningssystem, motivation och målkongruens. Efter att ha analyserat den insamlade empirin har författarna kommit fram till att belöningssystemet inte bidrar till att öka eller sänka graden av motivation på sikt, utan endast upprätthåller den nuvarande motivationsnivån. Det innebär att det aktuella belöningssystemet varken höjer eller sänker graden av motivation. I takt med att medarbetarna tar ett steg upp på karriärsstegen minskar betydelsen av det provisionsbaserade belöningssystemet. Faktorer som personlig utveckling och ansvar blir efterhand mer centrala faktorer än monetära belöningar i sin betydelse för motivationen. Genom att belöna prestationer som bidrar till organisationens övergripande mål, skapas målöverensstämmelse mellan medarbetare och organisation. Detta innebär i praktiken att medarbetarna måste arbeta mot företagets målsättningar för att ha möjlighet att nå sina individuella mål.Drawing from previous research on incentive-pay systems, motivation and goal congruence, this study focuses on the relationship between these subjects in order to find a link between motivation and incentive-pay systems and its effect on goal congruence. The study is based on a qualitative case study with an inductive approach. Empirical data were collected from six semi-structured interviews at Tele2 business to business-unit in Kista, Stockholm. The specific delimitation makes the results shown in this study non generalizable. The theoretical framework used for this study is based on theories of incentive pay-systems, motivation and goal congruence. The result of this study show that incentive pay-system does not increase nor decrease the level of motivation in a long term perspective, but simply helps to maintain the current level of motivation. The incentive pay-system diminishes as personal developement and increased responsibility becomes more of a crucial factor as the employee climbs the career ladder at Tele2. Furthermore, by rewarding performance that contributes to the overall goals of the organization, in this case increased revenue, goal congruence is created between the employee and the organization. This means that the employee is encouraged to work towards the organizational goals in order to have the opportunity to reach their individual goals

Nanobeam photonic crystal cavity quantum dot laser

The lasing behavior of one dimensional GaAs nanobeam cavities with embedded InAs quantum dots is studied at room temperature. Lasing is observed throughout the quantum dot PL spectrum, and the wavelength dependence of the threshold is calculated. We study the cavity lasers under both 780 nm and 980 nm pump, finding thresholds as low as 0.3 uW and 19 uW for the two pump wavelengths, respectively. Finally, the nanobeam cavity laser wavelengths are tuned by up to 7 nm by employing a fiber taper in near proximity to the cavities. The fiber taper is used both to efficiently pump the cavity and collect the cavity emission.Comment: 8 pages; 6 figure

Bright Room-Temperature Single Photon Emission from Defects in Gallium Nitride

Single photon emitters play a central role in many photonic quantum technologies. A promising class of single photon emitters consists of atomic color centers in wide-bandgap crystals, such as diamond silicon carbide and hexagonal boron nitride. However, it is currently not possible to grow these materials as sub-micron thick films on low-refractive index substrates, which is necessary for mature photonic integrated circuit technologies. Hence, there is great interest in identifying quantum emitters in technologically mature semiconductors that are compatible with suitable heteroepitaxies. Here, we demonstrate robust single photon emitters based on defects in gallium nitride (GaN), the most established and well understood semiconductor that can emit light over the entire visible spectrum. We show that the emitters have excellent photophysical properties including a brightness in excess of 500x10^3 counts/s. We further show that the emitters can be found in a variety of GaN wafers, thus offering reliable and scalable platform for further technological development. We propose a theoretical model to explain the origin of these emitters based on cubic inclusions in hexagonal gallium nitride. Our results constitute a feasible path to scalable, integrated on-chip quantum technologies based on GaN

Electrically controlled modulation in a photonic crystal nanocavity

We describe a compact modulator based on a planar photonic crystal nanocavity whose resonance is electrically controlled. A forward bias applied across a p-i-n diode shifts the cavity into and out of resonance with a continuous-wave laser field in a waveguide. The sub-micron size of the nanocavity promises extremely low capacitance, high bandwidth, and efficient on-chip integration in optical interconnects.Comment: 9 pages, 4 figure