Ståndortsindex och produktion för björk och gran på samma mark

På 11 lokaler där björk och gran vuxit i bestånd intill varandra på likartad mark uppskattades ståndortsindex (SI) för gran och björk med hjälp av brösthöjdsålder och höjd på övrehöjdsträd. På 22 lokaler (11 verkliga, 11 simulerade) uppskattades SI för gran och björk med hjälp av ståndortsegenskaper. Sambandet mellan SI för gran och för vårtbjörk sammanfattas i en tabell där SI G24 motsvarar B23 och SI G36 motsvarar B26. Marker där vårtbjörken kan konkurrera med granen i produktion bör vara friska lågörttyper med markvattenklass S eller K. Hög höjd över havet och nordliga breddgrader har också mer negativ påverkan på björkens än på granens tillväxt. På breddgrad 60-61 ºN  upp till 100 m över havet uppskattas då SI för björk till B24-26 och för gran till G25-27. På de lägre boniteterna (B23/G24) beräknas volymsproduktionen vara likvärdig för vårtbjörk och gran, medan på de högre boniteterna (B26/G36) beräknas granens medelvolyms-produktion vara upp mot dubbelt så hög som för vårtbjörk. Vårtbjörkens torrsubstansproduktion beräknas däremot överstiga den för gran på de lägre boniteterna och uppgå till ca 80% av granens torrsubstansproduktion på de högre boniteterna.  Materialet i studien är begränsat och försiktighet bör iakttagas vid generaliseringar.

A web application for follow-up of results from a mobile device test battery for parkinson’s disease patients

Background: A test battery consisting of self-assessments and motor tests (tapping and spiral drawing) was developed for a hand computer with touch screen in a telemedicine setting. Objectives: To develop and evaluate a web-based system that delivers decision support information to the treating clinical staff for assessing PD symptoms in their patients based on the test battery data. Methods: The test battery is currently being used in a clinical trial (DAPHNE, EudraCT No. 2005-002654-21) by sixty five patients with advanced Parkinson’s disease (PD) on 9991 test occasions (four tests per day during in all 362 week-long test periods) at nine clinics around Sweden. Test results are sent continuously from the hand unit over a mobile net to a central computer and processed with statistical methods. They are summarized into scores for different dimensions of the symptom state and an ‘overall test score’ reflecting the overall condition of the patient during a test period. The information in the web application is organized and presented graphically in a way that the general overview of the patient performance per test period is emphasized. Focus is on the overall test score, symptom dimensions and daily summaries. In a recent preliminary user evaluation, the web application was demonstrated to the fifteen study nurses who had used the test battery in the clinical trial. At least one patient per clinic was shown. Results: In general, the responses from nurses were positive. They claimed that the test results shown in the system were consistent with their own clinical observations. They could follow complications, changes and trends within their patients. Discussion: In conclusion, the system is able to summarise the various time series of motor test results and self-assessments during test periods and present them in a useful manner. Its main contribution is a novel and reliable way to capture and easily access symptom information from patients’ home environment. The convenient access to current symptom profile as well as symptom history provides a basis for individualized evaluation and adjustment of treatments.

High female mortality resulting in herd collapse in free-ranging domesticated reindeer (Rangifer tarandus tarandus) in Sweden

Reindeer herding in Sweden is a form of pastoralism practised by the indigenous Sami population. The economy is mainly based on meat production. Herd size is generally regulated by harvest in order not to overuse grazing ranges and keep a productive herd. Nonetheless, herd growth and room for harvest is currently small in many areas. Negative herd growth and low harvest rate were observed in one of two herds in a reindeer herding community in Central Sweden. The herds (A and B) used the same ranges from April until the autumn gathering in October-December, but were separated on different ranges over winter. Analyses of capture-recapture for 723 adult female reindeer over five years (2007-2012) revealed high annual losses (7.1% and 18.4%, for herd A and B respectively). A continuing decline in the total reindeer number in herd B demonstrated an inability to maintain the herd size in spite of a very small harvest. An estimated breakpoint for when herd size cannot be kept stable confirmed that the observed female mortality rate in herd B represented a state of herd collapse. Lower calving success in herd B compared to A indicated differences in winter foraging conditions. However, we found only minor differences in animal body condition between the herds in autumn. We found no evidence that a lower autumn body mass generally increased the risk for a female of dying from one autumn to the next. We conclude that the prime driver of the on-going collapse of herd B is not high animal density or poor body condition. Accidents or disease seem unlikely as major causes of mortality. Predation, primarily by lynx and wolverine, appears to be the most plausible reason for the high female mortality and state of collapse in the studied reindeer herding community.