Talousmetsien luonnonhoidon tehostamisen vaihtoehdot

Talousmetsien luonnonhoito on yleisnimitys toimille, joilla toteutetaan yleensä samanaikaisesti puuntuotannolle rinnakkaisia luonnon monimuotoisuutta tukevia toimenpiteitä met-sänkäsittelyssä. Talousmetsien luonnonhoidon keinovalikoima on laaja. Osa toimista on lähes maksuttomia metsänomistajalle mutta toiset merkittäviä kustannuksiltaan. Luonnonhoitoa metsien käsittelyn yhteydessä olisi mahdollista tehostaa nykyisestä. Kytkeytyneisyyden ja alueellisten ominaispiirteiden huomiointi luonnonhoidon toimien suunnittelussa ja toteuttamisessa lisäisivät luonnonhoidon toimien vaikuttavuutta. Kaikkiaan tehostaminen edellyttää luonnonhoidon laaja-alaista huomioimista metsäalan koko toimintakentässä. Luonnonhoidon lainsäädännön, ohjeistuksen ja kannustimien tulisi tukea metsänomistajia ja metsäalan operatiivisia toimijoita heidän jokapäiväisessä työssään ja päätöksenteossa. Uusia toimintamalleja tulisi kehittää ja testata. Luonnonhoidon ekologinen, sosiaalinen ja taloudellinen vaikuttavuus tehdään näkyväksi hyvin valituilla mittareilla ja seurannalla. Uutta tutkimustietoa luonnonhoidon vaikuttavuudesta saadaan ja tarvitaan meneillään olevista pitkäkestoisista tutkimussarjoista.Tämä julkaisu on toteutettu osana valtioneuvoston selvitys- ja tutkimussuunnitelman toimeenpanoa.(tietokayttoon.fi) Julkaisun sisällöstä vastaavat tiedon tuottajat, eikä tekstisisältö välttämättä edusta valtioneuvoston näkemystä

Adsorptive uptake of water by semisolid secondary organic aerosols

Aerosol climate effects are intimately tied to interactions with water. Here we combine hygroscopicity measurements with direct observations about the phase of secondary organic aerosol (SOA) particles to show that water uptake by slightly oxygenated SOA is an adsorption-dominated process under subsaturated conditions, where low solubility inhibits water uptake until the humidity is high enough for dissolution to occur. This reconciles reported discrepancies in previous hygroscopicity closure studies. We demonstrate that the difference in SOA hygroscopic behavior in subsaturated and supersaturated conditions can lead to an effect up to about 30% in the direct aerosol forcinghighlighting the need to implement correct descriptions of these processes in atmospheric models. Obtaining closure across the water saturation point is therefore a critical issue for accurate climate modeling.Peer reviewe

F-RTO: A New Recovery Algorithm for TCP Retransmission Timeouts

Spurious TCP retransmission timeouts (RTOs) have been reported to be a problem on network paths involving links that are prone to sudden delays due to different reasons. Especially many wireless network technologies contain such links. Spurious retransmission timeouts often cause unnecessary retransmission of several segments, which is harmful for TCP performance. Recent proposals for avoiding unnecessary retransmissions after a spurious RTO require use of TCP options which must be implemented at both ends of the connection. We introduce a new TCP sender algorithm for recovery after a retransmission timeout and show that unnecessary retransmissions can be avoided without TCP options. The algorithm effectively avoids the unnecessary retransmissions after a spurious retransmission timeout, improving the TCP performance considerably. The algorithm is friendly towards other TCP connections, because it follows the congestion control principles and injects packets to the network at same rate as a conventional TCP sender. We implemented the algorithm and compared its performance to conventional TCP and Eifel TCP when RTOs occurred either due to sudden delays or due to packet losses. The results show that our algorithm either improves performance or gives similar throughput as the other TCP variants evaluated in different test cases

Determination of Elastic Parameters of Pharmaceutical Materials Using a Fiber Interferometer

In the development of pharmaceutical products the elastic parameters of excipients are studied to assume drug safety. The excipients and their coating affect the emission properties of the drug. To determine the elastic parameters, the powder bond material is first pressed into the shape of a rectangular beam. In commonly used 3-point bending measurements, there is a tendency to move from the elastic bending regime to the plastic bending regime which necessarily changes the result for the elastic parameter in question [1]. Another available method is based on photoacoustics, but it is limited to the elastic regime [2]. The goal of this study is to create a system that would allow for high accuracy testing of these materials from the low force elastic to high force plastic regimes while using the same apparatus.</p

Data Channel Service for Wireless Telephone Links

The characteristics of wireless telephone links are quite different from those of wireline links. In particular, standard TCP/IP performs poorly in an environment where these links are combined. We have designed and implemented a communication architecture for the efficient operation over an internetwork consisting of fixed networks and wireless telephone networks. In our architecture the Mobile-Connection Host is the bridge between the wired and wireless networks. It allows us to transparently replace TCP/IP over the wireless medium with a special transport service called the Mowgli Data Channel Service (MDCS). The MDCS is designed to take into account long latencies, narrow bandwidth, highly variable transmission delays, and sudden disconnections. As a result, the MDCS significantly improves the fault tolerance and performance of communication over wireless telephone links. In this paper we describe the MDCS and its implementation as the Mowgli Data Channel Protocol (MDCP). We also..

Enhanced Services for World-Wide Web in Mobile WAN Environment

Currently, the World-Wide Web (WWW) is the best-known and most widely used distributed multimedia application. By utilising the data services of a cellular telephone system, for example the digital GSM system, WWW can be brought to nomadic users. The advantage of using an existing cellular network like the GSM is that it takes care of terminal mobility, including location updates and handovers. The characteristics of cellular telephone links are, however, quite different from those of wireline links. The basic characteristics of any cellular telephone link are narrow bandwidth, highly variable transmission delays, and sudden disconnections. Therefore, such a link creates problems for WWW and other multimedia applications designed to operate with fast and reliable connections. WWW uses the HyperText Transfer Protocol (HTTP), which in turn is based on TCP. These protocols exhibit a number of performance problems in a wide-area mobile networks. In this paper we describe Mowgli..

Enhanced Communication Services for Mobile TCP/IP Networking

Modern digital cellular telephones and portable personal computers have created a new, practical, and challenging platform for distributed information processing. We have designed and implemented a communication architecture for the efficient integration of wired and wireless networks. The architecture is based on the principle of indirect interaction. The mediating interceptor, the Mobile-Connection Host, is the bridge between the wired and wireless networks. The architecture significantly improves the end-to-end performance of TCP/IP-based communication between mobile nodes and fixed hosts. The introduction of application-specific mediators in the mobile node and in the Mobile-Connection Host provides means for enhanced application-level functionality, better user-level control of the wireless link, and increased performance