Head-based pointing is an effective interface for those with limited hand control, though it may involve a learning curve due to discrepancies between desired pointer movement and actual system response to head motion. We theorize that individuals have unique head movement patterns for similar tasks, necessitating tailored mappings from head to pointer motion. This was explored by analyzing video data of participants tracking a moving target on-screen using head movements. The study found that using a select set of facial landmarks outperforms other methods, like focusing on the nose-tip or rotation angles, in aligning head and pointer movements. Despite this, there is still notable bias inherent in the simple affine mapping model used. Significant variations were observed in participants' head movements when responding to similar target paths, with diagonal movements showing a higher error rate. These insights could be crucial in creating new, personalized head-tracking interfaces, enhancing ease and efficiency.

The HIV-1 Rev protein mediates export of unspliced and singly spliced viral transcripts by binding to the Rev response element (RRE) and recruiting the cellular export factor CRM1. Here, we investigated the recruitment of Rev to the transcription sites of HIV-1 reporters that splice either post- or cotranscriptionally. In both cases, we observed that Rev localized to the transcription sites of the reporters and recruited CRM1. Rev and CRM1 remained at the reporter transcription sites when cells were treated with the splicing inhibitor Spliceostatin A (SSA), showing that the proteins associate with RNA prior to or during early spliceosome assembly. Fluorescence recovery after photobleaching (FRAP) revealed that Rev and CRM1 have similar kinetics as the HIV-1 RNA, indicating that Rev, CRM1, and RRE-containing RNAs are released from the site of transcription in one single export complex. These results suggest that cotranscriptional formation of a stable export complex serves as a means to ensure efficient export of unspliced viral RNAs.

Transcription is a stochastic process occurring mostly in episodic bursts. Although the local chromatin environment is known to influence the bursting behavior on long timescales, the impact of transcription factors (TFs)--especially in rapidly inducible systems--is largely unknown. Using fluorescence in situ hybridization and computational models, we quantified the transcriptional activity of the proto-oncogene c-Fos with single mRNA accuracy at individual endogenous alleles. We showed that, during MAPK induction, the TF concentration modulates the burst frequency of c-Fos, whereas other bursting parameters remain mostly unchanged. By using synthetic TFs with TALE DNA-binding domains, we systematically altered different aspects of these bursts. Specifically, we linked the polymerase initiation frequency to the strength of the transactivation domain and the burst duration to the TF lifetime on the promoter. Our results show how TFs and promoter binding domains collectively act to regulate different bursting parameters, offering a vast, evolutionarily tunable regulatory range for individual genes.

Fluid User Interfaces (Fl.UIs) are liquid-based touch surfaces that use computer vision to detect and interpret a range of tactile user inputs. While Fl.UIs have less input resolution than digital touch screens, they provide an excellent low-cost solution for rapidly prototyping non-rectilinear screen designs as well as exploring novel surface interaction techniques. Fabricated on a laser cutter using low-cost materials, Fl.UIs use unique shape outlines to displace an internal colored liquid to regions-of-interest for a camera. This paper presents a set of software tools that help users rapidly design, fabricate and author interactions with Fl.UIs. The robust construction and an unpowered surface makes Fl.UIs well-suited for outdoor and public installations. Our Fl.UIs prototyping tool encourages these uncommon "screens" to emerge in complex environments (i.e. urban spaces, benches, tables, fountains, sidewalks).

Conventional acquisition of three-dimensional (3D) microscopy data requires sequential z scanning and is often too slow to capture biological events. We report an aberration-corrected multifocus microscopy method capable of producing an instant focal stack of nine 2D images. Appended to an epifluorescence microscope, the multifocus system enables high-resolution 3D imaging in multiple colors with single-molecule sensitivity, at speeds limited by the camera readout time of a single image.

Live-cell imaging has revealed unexpected features of gene expression. Here using improved single-molecule RNA microscopy, we show that synthesis of HIV-1 RNA is achieved by groups of closely spaced polymerases, termed convoys, as opposed to single isolated enzymes. Convoys arise by a Mediator-dependent reinitiation mechanism, which generates a transient but rapid succession of polymerases initiating and escaping the promoter. During elongation, polymerases are spaced by few hundred nucleotides, and physical modelling suggests that DNA torsional stress may maintain polymerase spacing. We additionally observe that the HIV-1 promoter displays stochastic fluctuations on two time scales, which we refer to as multi-scale bursting. Each time scale is regulated independently: Mediator controls minute-scale fluctuation (convoys), while TBP-TATA-box interaction controls sub-hour fluctuations (long permissive/non-permissive periods). A cellular promoter also produces polymerase convoys and displays multi-scale bursting. We propose that slow, TBP-dependent fluctuations are important for phenotypic variability of single cells.

Tactile maps of indoor spaces have great potential for supporting pre-journey spatial learning by blind travelers. Due to the limited resolution of tactile sensing, though, only a limited amount of spatial detail can be embossed in a map at a certain scale. We conducted a focus group with blind participants in order to obtain some insight on the perceived utility of using multiple maps at different spatial scales, and thus different level of detail, to represent the interior of a building.