Benefits and Risks of Intercropping for Crop Resilience and Pest Management.

To combat climate change, farmers must innovate through ecological intensification to boost food production, increase resilience to weather extremes, and shrink the carbon footprint of agriculture. Intercropping (where alternative crops or noncrop plants are integrated with cash crops) can strengthen and stabilize agroecosystems under climate change by improving resource use efficiency, enhancing soil water holding capacity, and increasing the diversity and quality of habitat for beneficial insects that provide pollination services and natural pest control. Despite these benefits, intercropping has yet to be widely adopted due to perceived risks and challenges including decreased crop yield, increased management complexity, a steep learning curve for successful management, and increased susceptibility to pests. Here, we explore the major benefits of intercropping in agricultural systems for pest control and climate resilience reported in 24 meta-analyses, while addressing risks and barriers to implementation. Most studies demonstrate clear benefits of intercropping for weed, pathogen, insect pest control, relative yield, and gross profitability. However, relatively few studies document ecosystem services conferred by intercrops alongside labor costs, which are key to economic sustainability for farmers. In addition to clearer demonstrations of the economic viability of intercropping, farmers also need strong technical and financial support during the adoption process to help them troubleshoot the site-specific complexities and challenges of managing polycultures. Ecological intensification of agriculture requires a more strategic approach than simplified production systems and is not without risks and challenges. Calibrating incentive programs to reduce financial burdens of risk for farmers could promote more widespread adoption of intercropping.

[Experimental corneal imaging and corneal surgery with non-amplified femtosecond laser pulses]. / Experimentelle Hornhautbildgebung und Hornhautchirurgie mit nicht verstärkten Femtosekundenlaserpulsen.

BACKGROUND: Non-amplified femtosecond laser was used to induce multiphoton effects for corneal tissue imaging and for tissue ablation. MATERIAL AND METHODS: A non-amplified titanium-sapphire laser was coupled to a laser scanning microscope in order to examine human and porcine cornea. Tissue was subjected to imaging and lesions were created using identical optical pathways at pulse energies below 2 nJ. RESULTS: Cellular components and the extracellular matrix were selectively imaged by applying autofluorescence and second harmonic generation at submicron resolution. Intrastromal linear scanning at higher power resulted in luminescent plasma along the scanning line. Lesion width decreased with increasing tissue depth and increased with increasing laser power at the target. Light microscopy showed intact stromal tissue around the area of the lesion. CONCLUSIONS: High-resolution images as well as high precision tissue lesions were created in the cornea using low energy femtosecond laser pulses. Easy switching between tissue imaging and ablation seems to be suitable for diagnostic and therapeutic applications.

Precursors to avalanches in a granular monolayer.

We investigate the stability of a granular monolayer composed of spherical grains on an inclined plate. When the tilt angle alpha increases, some reorganizations are observed throughout the pile. The packing fraction rho of the packing evolves by successive jumps. Those discontinuous events precede the collapse of the pile at a critical angle alphac. The occurrence of precursors before avalanches is modeled by stop-and-go motions of blocks due to the competition between sliding friction and the Janssen effect [J. Durand, (Springer-Verlag, New York, 2000)].

Specific DNA binding and transactivation potential of recombinant, purified Stat5.

The signal transducers and activators of transcriptions (Stats) are central mediators of cytokine responses especially in hematopoietic cells. The detailed molecular mechanisms of Stat activation, particularly the role of post-translational modifications and co-operation with cellular transcription factors are subject to intense investigation. The phosphorylation of a tyrosine residue in the carboxyl terminal domain is a common characteristic for the biologically active state of all known Stats. We studied the biological potential of purified recombinant murine Stat5a and Stat5b. These proteins were expressed in Sf9 insect cells upon infection with Stat5 encoding baculoviruses. We also obtained the tyrosine phosphorylated, activated forms of the Stat5 proteins by expressing the tyrosine kinase Janus kinase2 (Jak) in the same cells through co-infection with a kinase encoding virus. After purification, only the tyrosine phosphorylated form was able to bind specifically in vitro to the Stat5 DNA response element. This activated form of Stat5 is also able to support specific cell free in vitro transcription of a gene with a Stat5 response element in its promoter region. The recombinant purified Stat5 proteins were treated with the tyrosine specific protein phosphatase or with potato acidic phosphatase, which removes phosphate groups from serine and tyrosine residues. Phosphatase treatment resulted in the loss of specific DNA binding ability. This property could be restored by an in vitro reaction with recombinant, purified EGF or PDGF receptor kinases. Tyrosine rephosphorylation in vitro also restored the transactivation potential of Stat5. This modification is, therefore, a sufficient prerequisite for transcriptional induction by Stat5.

A sequence of the CIS gene promoter interacts preferentially with two associated STAT5A dimers: a distinct biochemical difference between STAT5A and STAT5B.

Two distinct genes encode the closely related signal transducer and activator of transcription proteins STAT5A and STAT5B. The molecular mechanisms of gene regulation by STAT5 and, particularly, the requirement for both STAT5 isoforms are still undetermined. Only a few STAT5 target genes, among them the CIS (cytokine-inducible SH2-containing protein) gene, have been identified. We cloned the human CIS gene and studied the human CIS gene promoter. This promoter contains four STAT binding elements organized in two pairs. By electrophoretic mobility shift assay studies using nuclear extracts of UT7 cells stimulated with erythropoietin, we showed that these four sequences bound to STAT5-containing complexes that exhibited different patterns and affinities: the three upstream STAT binding sequences bound to two distinct STAT5-containing complexes (C0 and C1) and the downstream STAT box bound only to the slower-migrating C1 band. Using nuclear extracts from COS-7 cells transfected with expression vectors for the prolactin receptor, STAT5A, and/or STAT5B, we showed that the C1 complex was composed of a STAT5 tetramer and was dependent on the presence of STAT5A. STAT5B lacked this property and bound with a stronger affinity than did STAT5A to the four STAT sequences as a homodimer (C0 complex). This distinct biochemical difference between STAT5A and STAT5B was confirmed with purified activated STAT5 recombinant proteins. Moreover, we showed that the presence on the same side of the DNA helix of a second STAT sequence increased STAT5 binding and that only half of the palindromic STAT binding sequence was sufficient for the formation of a STAT5 tetramer. Again, STAT5A was essential for this cooperative tetrameric association. This property distinguishes STAT5A from STAT5B and could be essential to explain the transcriptional regulation diversity of STAT5.

A hand held two-channel vibro-tactile speech communication aid for the deaf: characteristics and results.

The OSCAR-project (Optimal Speech Communication Assistance for Residual Abilities) within the TIDE frame is aiming at processing the speech signal in such a way so that it can be more effectively aurally perceived than with an ordinary hearing aid in case of a very small residual hearing. In case of total deafness the code will be tactile and in some cases a multi modal approach will be tried. One of the sub-results of the OSCAR-project is a hand held vibro-tactile speech communication aid for profoundly hard of hearing and deaf persons. The main idea of the aid is that it should not be a general tactile hearing aid, but rather give optimum tactile support to lip-reading in a close communication situation. It should be used when speech communication is necessary and other methods of communication i.e. sign language, lip-reading, reading and writing etc. does not work. The aid conveys two types of information via its two vibro-tactile transducers; the syllabic rhythm and frication. This paper describes some characteristics of the aid and some results.

Structural changes in the antennapedia complex of Drosophila pseudoobscura.

The discovery of the striking positional conservation between the Antennapedia and Bithorax homeotic gene complexes (ANT-C and BX-C) in Drosophila melanogaster and the murine Hox and human HOX clusters has had a substantial impact on our understanding of the evolution of development and its genetic regulation. Structural differences do exist among the mammalian Hox complexes and the ANT-C in D. melanogaster. To gain further insight into the evolutionary changes among these complexes, the ANT-C was cloned in the closely related species, Drosophila pseudoobscura. The overall structure of the ANT-C in D. pseudoobscura is highly similar to its D. melanogaster counterpart; however, two differences in the organization of the ANT-C have been identified. First, the z2 gene, a member of the ANT-C in D. melanogaster, is not present in the D. pseudoobscura ANT-C and is possibly absent from the D. pseudoobscura genome. Second, the orientation of the Deformed gene is inverted in D. pseudoobscura, providing it with a 5' to 3' direction of transcription identical to the remaining ANT-C homeobox genes with the exception of fushi tarazu. These differences demonstrate that subtle changes can occur in ANT-C structure during relatively short periods of evolutionary divergence, although the fundamental organization of the complex is conserved. These observations and others suggest that the complex is not absolutely rigid but that selective pressures have maintained this organization of genes for some functional reason that remains elusive.

Myositis ossificans of the upper arm.

Myositis ossificans is a benign condition resulting from severe muscular contusion manifested by heterotrophic bone formation. The process is common in the anterior thigh but the literature dealing with myositis ossificans in the upper arm is limited. Ten cases of the condition in the upper arm were seen in our practice. All 10 were the result of football injuries and exhibited one or more of the triad of local pain, a hard palpable mass in the muscle, and a flexion contracture of the elbow. Seven of the cases (70%) were asymptomatic or signficantly improved in less than 3 months with conservative nonoperative management. Three patients (30%) underwent surgery because the painful mass persisted. In two (66%) of the surgically managed cases, there was clinical and radiographic evidence of recurrence postoperatively in spite of delaying excision until radiographic parameters of maturation were present.