On the available evidence for the temperature dependence of soil organic carbon

International audienceTwo recent papers by Knorr et al. (2005) and Fang et al. (2005) provide variations of model fitting conducted in the former study. Knorr et al. (2005) suggested that more recalcitrant fractions of soil organic carbon (SOC) could be more sensitive to temperature. Fang et al. (2005) argue that this is an implication of the choice of model used. Further, Reichstein et al. (2005) point out that the evidence for a stronger temperature sensitivity of recalcitrant soil carbon mainly rests on an analysis of data provided by Kätterer et al. (1998) and argue for a different selection criterion to exclude short-term incubations. Here, we explain why the model used by Knorr et al. (2005) is the simplest multi-pool model that can fit the available data and is at the same time fully consistent with the concept of "pools", as opposed to some of the model formulations proposed by Fang et al. (2005). It is also pointed out that the criterion proposed by Reichstein et al. (2005) uses posterior information to determine inclusion of experimental data, a practice that should be avoided. We conclude that the original analysis of Knorr et al. (2005) as well as the one added by Fang et al. (2005) indicate that there is a serious possibility that recalcitrant SOC reacts more to temperature changes than labile SOC

Perceptions of knowledge sharing among small family firm leaders: a structural equation model

Small family firms have many unique relational qualities with implications for how knowledge is passed between individuals. Extant literature posits leadership approach as important in explaining differences in knowledge-sharing climate from one firm to another. This study investigates how leadership approaches interact with family influence to inform perceptions of knowledge sharing. We utilize survey data (n = 110) from owner-managers of knowledge-intensive small family firms in Scotland. Our findings present a choice in leadership intention, contrasting organization-focused participation against family-influenced guidance. Insight is offered on the implications of this leadership choice at both organizational and familial level

Case report: Severe mercuric sulphate poisoning treated with 2,3-dimercaptopropane-1-sulphonate and haemodiafiltration

INTRODUCTION: Inorganic mercury poisoning is uncommon, but when it occurs it can result in severe, life-threatening features and acute renal failure. Previous reports on the use of extracorporeal procedures such as haemodialysis and haemoperfusion have shown no significant removal of mercury. We report here the successful use of the chelating agent 2,3-dimercaptopropane-1-sulphonate (DMPS), together with continuous veno-venous haemodiafiltration (CVVHDF), in a patient with severe inorganic mercury poisoning. CASE REPORT: A 40-year-old man presented with haematemesis after ingestion of 1 g mercuric sulphate and rapidly deteriorated in the emergency department, requiring intubation and ventilation. His initial blood mercury was 15 580 μg/l. At 4.5 hours after ingestion he was started on DMPS. He rapidly developed acute renal failure and so he was started on CVVHDF for renal support and in an attempt to improve mercury clearance; CVVHDF was continued for 14 days. METHODS: Regular ultradialysate and pre- and post-filtrate blood samples were taken and in addition all ultradialysate generated was collected to determine its mercury content. RESULTS: The total amount of mercury in the ultrafiltrate was 127 mg (12.7% of the ingested dose). The sieving coefficient ranged from 0.13 at 30-hours to 0.02 at 210-hours after ingestion. He developed no neurological features and was discharged from hospital on day 50. Five months after discharge from hospital he remained asymptomatic, with normal creatinine clearance. DISCUSSION: We describe a patient with severe inorganic mercury poisoning in whom full recovery occurred with the early use of the chelating agent DMPS and CVVHDF. There was removal of a significant amount of mercury by CVVHDF. CONCLUSION: We feel that CVVHDF should be considered in patients with inorganic mercury poisoning, particularly those who develop acute renal failure, together with meticulous supportive care and adequate doses of chelation therapy with DMPS

Notes on Ipomoea L. (Convolvulaceae) in Cuba and neighbouring islands with a checklist of species found in Cuba

An updated checklist of species of Ipomoea L. found in Cuba is presented with analysis of the different elements represented. I. alterniflora Griseb. is defined broadly to include I. obtusata Griseb. and I. excisa Urb. and its differences from the little-known I. cubensis (House) Urb. are discussed. I. calophylla C. Wright ex Griseb. is reinstated as the correct name for the species generally known as I. lacteola House. I. praecox C. Wright is recognised as a distinct species from I. argentifolia A. Rich. and images are provided to help distinguish the two species. I. flavopurpurea Urb. and I. dajabonensis Alain are shown to be conspecific with I. longeramosa Choisy, whose disjunct distribution is mapped and discussed. The little-known I. montecristina Hadač is described and illustrated and the cited collections show it to be locally common in the Guantánamo region. I. microdonta J. R. I. Wood and Scotland is described as new from Camagüey in central Cuba. Eight species endemic to Cuba collected by Ekman and described by Urban in 1924 – 25 are evaluated but only two, I. balioclada Urb. and I. erosa Urb., are deemed to warrant recognition as distinct endemic species. The origin and typification of I. horsfalliae Hook. are discussed and an epitype designated. Cultivated plants named I. horsfalliae occur in many tropical countries including Cuba but their extreme variation suggests hybrid origin. Four species from Jamaica, I. rubella House, I. lineolata Urb., I. carmesina Proctor and the Jamaican plant called I. horsfalliae are treated as synonyms of a variable I. lineolata, which is endemic to the island. I. saxicola Proctor is treated as var. saxicola J. R. I. Wood and Scotland of I. ternata Jacq. I. cyanantha Griseb. is treated as a synonym of I. lindenii M. Martens and Galeotti. Lectotypes are designated for I. cyanantha, I. lindenii, I. praecox, I. punctata C. Wright, I. geranioides Meisn. and I. grisebachii Urb

Measures Matter: Scales for Adaptation, Cultural Distance, and Acculturation Orientation Revisited

Building upon existing measures, four new brief acculturation scales are presented, measuring sociocultural adaptation, psychological adaptation, perceived cultural distance, and acculturation orientation. Following good scale reliability in initial samples, the English scales were translated into nine different languages (Chinese, French, German, Italian, Japanese, Portuguese, Spanish, Thai, and Turkish). The translated scales were administered to a large sample of sojourners (N = 1,929), demonstrating good reliability and adequate structural equivalence across languages. In line with existing theory, sociocultural adaptation and psychological adaptation were positively correlated, and showed a negative association with perceived cultural distance. General measures of well-being were correlated with adaptation and distance, with better adaptation relating to higher well-being, and more distance relating to lower well-being. Acculturation orientation toward the home and host culture were measured separately and a weak negative correlation was found between the two, supporting their independence. Arguing against dichotomization, these subscales were analyzed as continuous variables. Regression analysis showed sojourners to be better adapted, if they were oriented more toward the host culture and less toward the home culture. These new scales are proposed as alternatives to existing measures

Speech Communication

Contains reports on two research projects.National Science FoundationUnited States Air Force, Cambridge Research Center, Air Research and Development Command (Contract AF19(604)-6102)United States Navy, Office of Naval Research (Contract Nonr-1841(42)

Judging the impact of leadership-development activities on school practice

The nature and effectiveness of professional-development activities should be judged in a way that takes account of both the achievement of intended outcomes and the unintended consequences that may result. Our research project set out to create a robust approach that school staff members could use to assess the impact of professional-development programs on leadership and management practice without being constrained in this judgment by the stated aims of the program. In the process, we identified a number of factors and requirements relevant to a wider audience than that concerned with the development of leadership and management in England. Such an assessment has to rest upon a clear understanding of educational leadership,a clearly articulated model of practice, and a clear model of potential forms of impact. Such foundations, suitably adapted to the subject being addressed, are appropriate for assessing all teacher professional development

Rotation Measure Synthesis of Galactic Polarized Emission with the DRAO 26-m Telescope

Radio polarimetry at decimetre wavelengths is the principal source of information on the Galactic magnetic field. The diffuse polarized emission is strongly influenced by Faraday rotation in the magneto-ionic medium and rotation measure is the prime quantity of interest, implying that all Stokes parameters must be measured over wide frequency bands with many frequency channels. The DRAO 26-m Telescope has been equipped with a wideband feed, a polarization transducer to deliver both hands of circular polarization, and a receiver, all operating from 1277 to 1762 MHz. Half-power beamwidth is between 40 and 30 arcminutes. A digital FPGA spectrometer, based on commercially available components, produces all Stokes parameters in 2048 frequency channels over a 485-MHz bandwidth. Signals are digitized to 8 bits and a Fast Fourier Transform is applied to each data stream. Stokes parameters are then generated in each frequency channel. This instrument is in use at DRAO for a Northern sky polarization survey. Observations consist of scans up and down the Meridian at a drive rate of 0.9 degree per minute to give complete coverage of the sky between declinations -30 degree and 90 degree. This paper presents a complete description of the receiver and data acquisition system. Only a small fraction of the frequency band of operation is allocated for radio astronomy, and about 20 percent of the data are lost to interference. The first 8 percent of data from the survey are used for a proof-of-concept study, which has led to the first application of Rotation Measure Synthesis to the diffuse Galactic emission obtained with a single-antenna telescope. We find rotation measure values for the diffuse emission as high as approximately 100 rad per square metre, much higher than recorded in earlier work.Comment: Accepted for publication in The Astronomical Journa