Quantitative Imaging of Protein-Protein Interactions by Multiphoton Fluorescence Lifetime Imaging Microscopy using a Streak camera

Fluorescence Lifetime Imaging Microscopy (FLIM) using multiphoton excitation techniques is now finding an important place in quantitative imaging of protein-protein interactions and intracellular physiology. We review here the recent developments in multiphoton FLIM methods and also present a description of a novel multiphoton FLIM system using a streak camera that was developed in our laboratory. We provide an example of a typical application of the system in which we measure the fluorescence resonance energy transfer between a donor/acceptor pair of fluorescent proteins within a cellular specimen.Comment: Overview of FLIM techniques, StreakFLIM instrument, FRET application

Southern Hemisphere automated supernova search

The Perth Astronomy Research Group has developed an automated supernova search program, using the 61 cm Perth–Lowell reflecting telescope at Perth Observatory in Western Australia, equipped with a CCD camera. The system is currently capable of observing about 15 objects per hour, using 3 min exposures, and has a detection threshold of 18th–19th magnitude. The entire system has been constructed using low‐cost IBM‐compatible computers. Two original discoveries (SN 1993K, SN 1994R) have so far been made during automated search runs. This paper describes the hardware and software used for the supernova search program, and shows some preliminary results from the search system

Electrophonic sounds from the re-entry of the Molniya 1-67 satellite over Australia: Confirmation of the electromagnetic link.

Accepted versio

Section 230 and the Problem of Social Cost

This Article employs, with certain modifications, the framework developed in Ronald Coase’s classic article, “The Problem of Social Cost,” to analyze the current debate over Section 230 of the Communications Decency Act. This provision absolves interactive computer services, also known as platforms, from liability when they disseminate materials that cause “harm” to third parties, “harm” that can take the form of compensable damage of a sort found in ordinary tort cases but also can include broader injuries to social order and cohesion in the form of such things as hate speech and misinformation. The Article begins by pointing out that, as Coase observes, the ability of private markets to deal with such externalities is limited when the harmful effects are widely distributed, so that many of the entities that are harmed do not have incentives to bring private actions against their sources. It also notes that this problem is compounded in the case of information that is distributed over the internet because of the difficulties involved in identifying, and obtaining jurisdiction over, the ultimate sources of such information. For that reason, it concludes that private actions to limit the dissemination of harmful materials are likely to be more effective if interactive computer services, in addition to information sources, can be held liable by their victims both because the services will often be easier to identify and because they have greater ability to engage in content moderation. However, it also observes that this is likely to be of limited effectiveness, in part because of the difficulties of bringing private actions against these services both because of the cost, delay, and uncertainty of litigation and because some services may obtain substantial economic benefits when they disseminate harmful information. For these reasons, the Article concludes that policy makers should consider expanding the range of carve outs, provisions that eliminate the immunity from liability that interactive computer services currently enjoy when they are involved in the dissemination of certain types of harmful materials, and that empowering the government to bring civil actions against interactive computer services for disseminating specific types of harmful information should also be considered

Homologous association of the Bithorax-Complex during embryogenesis: consequences for transvection in Drosophila melanogaster

Transvection is the phenomenon by which the expression of a gene can be controlled by its homologous counterpart in trans, presumably due to pairing of alleles in diploid interphase cells. Transvection or trans-sensing phenomena have been reported for several loci in Drosophila, the most thoroughly studied of which is the Bithorax-Complex (BX-C). It is not known how early trans-sensing occurs nor the extent or duration of the underlying physical interactions. We have investigated the physical proximity of homologous genes of the BX-C during Drosophila melanogaster embryogenesis by applying fluorescent in situ hybridization techniques together with high resolution confocal light microscopy and digital image processing. The association of homologous alleles of the BX-C starts in nuclear division cycle 13, reaches a plateau of 70% in post-gastrulating embryos, and is not perturbed by the transcriptional state of the genes throughout embryogenesis. Pairing frequencies never reach 100% indicative that the homologous associations are in equilibrium with a dissociated state. We determined the effects of translocations and a zeste protein null mutation, both of which strongly diminish transvection phenotypes, on the extent of diploid homologue pairing. Surprisingly, the pairing of homologous alleles was reduced, albeit only to 20 - 30%, by translocating one allele of the BX-C from the right arm of chromosome 3 to the left arm of chromosome 3 or to the X chromosome although trans-regulation of the Ultrabithorax gene was abolished. A zeste protein null mutation neither delayed the onset of pairing nor led to unpairing of the homologous alleles. These data are discussed in light of different models for trans-regulation. We examined the onset of pairing of the chromosome 4 as well as of loci near the centromere of chromosome 3 and near the telomere of 3R in order to test models for the mechanism of homologue pairing

“Time Is A-Wasting”: Making the Case for CEDAW Ratification by the United States

Since President Carter signed the Convention for the Elimination of All Forms of Discrimination Against Women (the “CEDAW” or the “Convention”) on July 17, 1980, the United States has failed to ratify the Convention time and again. As one of only a handful of countries that has not ratified the CEDAW, the United States is in the same company as Sudan, Somalia, Iran, Tonga, and Palau. When CEDAW ratification stalled yet again in 2002, then-Senator Joseph Biden lamented that “[t]ime is a-wasting.” Writing in 2002, Harold Koh, former Assistant Secretary of State for Democracy, Human Rights, and Labor, bemoaned America’s abdication of its moral leadership: “From my direct experience as America’s chief human rights official, I can testify that our continuing failure to ratify CEDAW has reduced our global standing . . . hindered our ability to lead in the international human rights community . . . [and] challenge[d] our claim of moral leadership in international human rights . . . .” Today, ratifying the CEDAW would undoubtedly be an important foreign policy tool and would communicate to the global community that the United States considers dismantling all forms of discrimination to be an inalienable and universal obligation. However, we argue that the value of ratifying the CEDAW is not limited to its foreign policy implications: At a time of a mass public reckoning on equality, ratifying the Convention would also be a central vehicle for change for women in America, including minority women, to claim their rights in courts, in work-places, and in the family. Our study is a tour de force of the CEDAW’s impetus for progressive legal changes around the world and an exegesis of its intersections along the axes of security and minority status. The language of the Convention allows each State Party to use “all appropriate measures” to implement legislation to eliminate discrimination and take “all appropriate measures, including legislation” to promote de jure and de facto equality between men and women. Although a causal link cannot always be proven, the very language of the laws of surveyed countries reflects the CEDAW Committee’s Concluding Observations and General Recommendations. Despite challenges to the CEDAW’s implementation and the imperfect commitments of the 189 ratifying states, the Convention stands as the central vehicle for the incorporation of women’s rights norms into national laws and practice. The Biden Administration should waste no more time in ratifying the CEDAW and joining the international community as it seeks to bring women and girls to the center of our current global recovery. As we write these words, the Taliban has taken control of Afghanistan. The United States must signal its renewed commitment to multilateralism and women’s equality by joining the global bill of rights for women