Implications of tropical cyclones on damage and potential recovery and restoration of logged forests in Vietnam.

Many natural forests in Southeast Asia are degraded following decades of logging. Restoration of these forests is delayed by ongoing logging and tropical cyclones, but the implications for recovery are largely uncertain. We analysed meteorological, satellite and forest inventory plot data to assess the effect of Typhoon Doksuri, a major tropical cyclone, on the forest landscapes of central Vietnam consisting of natural forests and plantations. We estimated the return period for a cyclone of this intensity to be 40 years. Plantations were almost twice as likely to suffer cyclone damage compared to natural forests. Logged natural forests (9-12 years after cessation of government-licensed logging) were surveyed before and after the storm with 2 years between measurements and remained a small biomass carbon sink (0.1 ± 0.3 Mg C ha-1 yr-1) over this period. The cyclone reduced the carbon sink of recovering natural forests by an average of 0.85 Mg C ha-1 yr-1, less than the carbon loss due to ongoing unlicensed logging. Restoration of forest landscapes in Southeast Asia requires a reduction in unlicensed logging and prevention of further conversion of degraded natural forests to plantations, particularly in landscapes prone to tropical cyclones where natural forests provide a resilient carbon sink. This article is part of the theme issue 'Understanding forest landscape restoration: reinforcing scientific foundations for the UN Decade on Ecosystem Restoration'.

Compact optical imaging system for arrays of optical thyristors.

A compact and modular optical system that employs gradient-refractive-index rod lenses to image arrays of Lambertian sources is characterized both experimentally and by ray-tracing simulations. A hybrid optical system that incorporates additional microlens arrays to reduce transmittance losses and aberrations is also modeled, and the two systems are compared.

Hemodynamic stability during different forms of dialysis therapy: a pathogenetic analysis.

Pathophysiological aspects of plasma volume preservation and cardiovascular reactivity are reviewed, comparing combined ultrafiltration-hemodialysis with isolated ultrafiltration and hemofiltration. The role of different factors in the disparity in cardiovascular reactivity between these treatments is discussed.

Integration of refractive micro-optical elements with differential-pair optical-thyristor arrays.

We demonstrate a refractive micr-optical system by using ion-exchange microlenses and microprisms, which are combined to generate a superposition of two shifted images. The microlenses, fabricated with field-assisted Ag-Na exchange, achieve diffraction-limited imaging with a single-lens system and with a double-lens system for a field of 800 µm × 800 µm. Furthermore, we demonstrate cascading of two separate differential-pair optical-thyristor arrays by transcribing the information of a source array onto a second destination array.

Localization of amidating enzymes (PAM) in rat gastrointestinal tract.

We studied the distribution of the two enzymes involved in post-translational C-terminal alpha-amidation of regulatory peptides in rat digestive tract, using immunocytochemical methods and in situ hybridization techniques. The enzymes were located in most of the fibers and neurons of the myenteric and submucous plexus throughout the entire digestive tract and in endocrine cells of the stomach and colon. Staining of reverse-face serial sections demonstrated that the enzymes in endocrine cells of the stomach co-localized with gastrin in the bottom of the gastric glands. Some gastrin-immunoreactive cells near the neck of the gland were negative for PAM, suggesting that amidation takes place only in the more mature cells. In the colon all cells immunoreactive for glucagon and GLP1 were also positive for peptidylglycine alpha-hydroxylating monooxygenase (PHM) but not for peptidyl-alpha-hydroxyglycine alpha-amidating lyase (PAL). The absence of immunoreactivity for the amidating enzymes in endocrine cells of the small intestine, known to produce C-terminally amidated peptides, suggests the existence of other amidating enzymes.

Maximum detection with a two-dimensional optoelectronic p-n-p-n winner-take-all network.

An optoelectronic p-n-p-n winner-take-all network is presented that can identify the location of the maximum intensity in two-dimensional spatially distributed light. An input pattern of illumination is incident upon an array of p-n-p-n devices that are connected in parallel to a common load resistor and therefore have identical voltage biases. If the light intensity at one or several elements exceeds a threshold value, only one p-n-p-n element stays on and emits light when the input light pattern is turned off. The element that is turned on is the one that receives the maximum illumination.

Characterization of virus DNA synthesized in KB cells infected with two temperature-sensitive mutants of adenovirus type 5.

KB cells were infected with H5ts36 or H5ts125, two adenovirus type 5 (Ad5) mutants with a temperature-sensitive synthesis of virus DNA. Infection was started at the nonpermissive temperature and at 16 h p.i. the temperature was shifted down to the permissive temperature. Shortly after the shift-down H5ts125-infected cells showed an accumulation of purely single-stranded DNA of virus origin, which was not observed in H5ts36-infected cells. This single-stranded DNA has been characterized by hybridization and sedimentation analysis. It was found that the single-stranded DNA was derived from both complementary strands and consisted of short fragments. The observation that the single-stranded DNA accumulates in H5ts125-infected cells under conditions in which the amount of DNA binding protein is reduced, suggests that the DNA-binding protein is not only involved in initiation, but also in elongation of nascent strands.

The mechanism of replication of adenovirus type 5 DNA.

The analysis of replicating Ad5 DNA has led to a model for replication involving linear intermediates. The origin of replication has been localized at the molecular right end, suggesting the presence of a unique sequence of nucleotides which can be recognized by an initiation factor. On the other hand, the study of the molecular ends has shown, so far, a high degree of symmetry in the terminal nucleotide sequences of Ad5 DNA. A more detailed study of the nucleotide sequences at the ends is necessary to solve this problem.