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Background: Sedentary behaviour is associated with cardiometabolic diseases amongst office-bound workers, mostly through extended sitting and engaging in low-energy-demanding activities during work hours. The aim of this study is to assess the effectiveness of standing desks and healthy messages on cardiovascular parameters in a cohort of office-based workers and to explore the perceptions of these workers about the suitability of this intervention to lower occupation-related sedentariness. Methods/design: The protocol will use a mixed-methods study design. Phase 1 of this study is a 12-month, single blinded, randomised controlled trial, which will include baseline, 3-month, 6-month and 12-month post-intervention assessments of plausible cardiometabolic risk biomarkers in office-bound workers at a South African credit and information management company. These biomarkers include anthropometry, sedentary behaviour and physical activity, sleep duration, blood pressure, glucose, glycated haemoglobin (HbA1c), lipid profile and cardiorespiratory fitness. Participants will be randomised into an intervention or control group. The intervention group will be provided with an adjustable sit–stand desk and receive weekly health-promoting messages for the intervention period. Phase 2 will use focus group discussions conducted post-intervention to explore the study participants’ perceptions of the effectiveness of the intervention. Cardiometabolic risk biomarkers and changes in these variables will be compared between the intervention group and the control group at the four time points using descriptive and inferential statistics. Discussion: Regression analysis will be undertaken to determine the association of cardiometabolic risk biomarkers with cardiometabolic diseases. A thematic content analysis approach will be used to explore emerging themes from focus group discussions. Protocol identification: Pan African Clinical Trial Registry, PACTR201911656014962.

In this case report, we focus on Muenke syndrome (MS), a disease caused by the p.Pro250Arg variant in fibroblast growth factor receptor 3 (FGFR3) and characterized by uni- or bilateral coronal suture synostosis, macrocephaly without craniosynostosis, dysmorphic craniofacial features, and dental malocclusion. The clinical findings of MS are further complicated by variable expression of phenotypic traits and incomplete penetrance. As such, unraveling the mechanisms behind MS will require a comprehensive and systematic way of phenotyping patients to precisely identify the impact of the mutation variant on craniofacial development. To establish this framework, we quantitatively delineated the craniofacial phenotype of an individual with MS and compared this to his unaffected parents using three-dimensional cephalometric analysis of cone beam computed tomography scans and geometric morphometric analysis, in addition to an extensive clinical evaluation. Secondly, given the utility of human induced pluripotent stem cells (hiPSCs) as a patient-specific investigative tool, we also generated the first hiPSCs derived from a family trio, the proband and his unaffected parents as controls, with detailed characterization of all cell lines. This report provides a starting point for evaluating the mechanistic underpinning of the craniofacial development in MS with the goal of linking specific clinical manifestations to molecular insights gained from hiPSC-based disease modeling.

Temsirolimus has long been the only approved first-line standard of care (SOC) with overall survival (OS) benefit in poor-risk patients with advanced or metastatic renal cell cancer (mRCC). However, tyrosine kinase inhibitors are also commonly used in clinical practice. Pazopanib is an SOC for first-line mRCC treatment, but for poor-risk patients data are scarce. The FLIPPER (First-Line Pazopanib in Poor-Risk Patients with Metastatic Renal Cell Carcinoma) study aimed to assess efficacy and safety of first-line pazopanib in poor-risk mRCC patients. FLIPPER was a single-arm, multicenter, Phase IV trial. Key inclusion criteria were treatment-naive clear cell, inoperable advanced or mRCC, poor-risk according to MSKCC with slight modification, Karnofsky performance status (KPS) ≥60% and adequate organ function. Oral pazopanib 800 mg was given daily. Primary endpoint was the 6-month progression-free survival rate (PFS6). Secondary endpoints included PFS, OS, overall response rate (ORR), duration of response (DOR) and safety. For analysis, descriptive statistics were used. Between 2012 and 2016, 60 patients had been included. Forty-three patients qualified for safety analyses, 34 for efficacy. Median age was 66 years, 64.7% of patients were poor-risk, 82.4% had a KPS ≤70%. PFS6 was 35.3% (95% CI, 19.7-53.5). Median PFS and OS were 4.5 months (95% CI, 3.6-7.8) and 9.3 months (95% CI, 6.6-22.2), respectively. ORR was 32.4% (95% CI, 17.4-50.5), median DOR 9.7 months (95% CI, 1.8-12.4). The most common treatment-related grade 3/4 adverse event reported in 4.7% of patients was hypertension. No treatment-related death occurred. Since pazopanib is active and well tolerated in poor-risk patients with clear cell mRCC, our results support its use as first-line treatment in this setting.

IP multicast (IPMC) delivers one-to-many traffic along distribution trees. To that end, conventional IPMC requires state in forwarding devices for each IPMC group. This limits scalability of IPMC because forwarding state in core devices may be extensive and updates are necessary when IPMC groups or the topology change. The IETF introduced Bit Index Explicit Replication (BIER) for efficient transport of IPMC traffic. BIER leverages a BIER header and IPMC-group-independent forwarding tables for forwarding of IPMC packets in a BIER domain. However, legacy devices do not support BIER. In contrary, two SDN-based implementations for OpenFlow an P4 have been published recently. In this paper, we assess BIER forwarding which may be affected by network failures. So far there is no standardized procedure to handle such situations. Two concepts have been proposed. The first approach is based on Loop- Free Alternates. It reroutes traffic to suitable neighbors in the BIER domain to steer traffic around the failure. The second approach is a tunnel-based mechanism that tunnels BIER packets to appropriate downstream nodes within the BIER distribution tree. We explain and compare both approaches, and discuss their advantages and disadvantages.

1+1 protection is a method to secure traffic between two nodes against failures in between. The sending node duplicates the traffic and forwards it over two disjoint paths. The receiving node assures that only a single copy of the traffic is further forwarded to its destination. In contrast to other protection schemes, this method prevents almost any packet loss in case of failures. 1+1 protection is usually applied on the optical layer, on Ethernet, or on MPLS. In this work we propose the application of 1+1 for P4-based IP networks. We define an 1+1 protection header for that purpose. We describe the behavior of sending and receiving nodes and provide a P4-based implementation for the BMv2 software switch and the hardware switch Tofino Edgecore Wedge 100BF-32X. We illustrate how to secure traffic, e.g. individual TCP flows, on the Internet with this approach. Finally, we present performance results showing that the P4-based implementation efficiently works on the Tofino Edgecore Wedge 100BF-32X., 5 pages, 4 figures

Esophageal cancer is the eighth most common malignancy worldwide, producing a high morbidity and mortality rate around the globe. Minimally invasive esophagectomy (MIE) is most commonly performed on patients with this devastating disease. Esophagectomy is a high-risk procedure, and perioperative mortality remains around 5%–8%. Because esophageal cancer is associated with chronic alcohol and tobacco use, patients have serious comorbid conditions that affect anesthetic management and perioperative care. Among them, pulmonary complications and anastomotic failure remain the most common causes of perioperative morbidity and mortality. The anesthesiologist managing a patient during MIE must be able to reduce the effect of the patient’s multiple comorbidities intraoperatively while mitigating the factors that lead to adverse postoperative outcomes.

Bit Indexed Explicit Replication (BIER) is a novel IP multicast (IPMC) forwarding paradigm proposed by the IETF. It offers a transport layer for other IPMC traffic, keeps core routers unaware of IPMC groups, and utilizes a routing underlay, e.g., an IP network, for its forwarding decisions. With BIER, core networks do not require dynamic signaling and support a large number of IPMC groups with large churn rates. The contribution of this work is threefold. First, we propose a novel fast reroute (FRR) mechanism for BIER (BIER-FRR) so that IPMC traffic can be rerouted as soon as the routing underlay is able to carry traffic again after a failure. In particular, BIER-FRR enables BIER to profit from FRR mechanisms in the routing underlay. Second, we describe a prototype for BIER and BIER-FRR within an IP network with IP fast reroute (IP-FRR). It is based on the programmable data plane technology P4. Third, we propose a controller hierarchy with local controllers for local tasks, in particular to enable IP-FRR and BIER-FRR. The prototype demonstrates that BIER-FRR reduces the protection time for BIER traffic to the protection time for unicast traffic in the routing underlay.

Software-defined networks (SDN) usually require intervention of a controller to restore connectivity in case of link or node failures. To avoid this dependence, a fast failover function enables switches to locally detect a failure and deviate affected traffic. In this paper, we develop fast reroute (FRR) methods leveraging that feature and the principle of loop-free alternates (LFAs) from IP networks for network-wide configuration. We explain how LFAs, remote LFAs, and novel explicit-path LFAs may be implemented with OpenFlow so that SDN with general destination-based routing can be protected. An advanced loop detection and termination function is suggested to prevent loops that may be caused by FRR in case of severe failures. We evaluate the FRR methods on a large set of representative network topologies and compare them with existing FRR methods. Classic rLFAs from IP networks generate many loops in case of node failures so that they are not appropriate for SDN. One developed protection method is particularly suitable for SDN as it can protect all flows in a network against any single link and node failure. The solution is efficient because it secures most traffic also in case of dual failures, leads to short backup paths, and requires in most networks only a few additional forwarding entries per node. The latter is important as OpenFlow switches can accommodate only a moderate number of forwarding entries in their flow tables.

Resilient networks react to a failure by reconfiguring routing tables in a network-wide manner and utilizing fast reroute (FRR) in the meanwhile. FRR uses pre-computed backup paths to avoid the failure locally. The existing FRR approaches for IP networks and Software-Defined Networking (SDN) differ in regard to computational complexity, backup path length, additional forwarding state and required capacities. Maximally Redundant Trees (MRTs) are standardized by the IETF and are already available for IP and MPLS networks. In this paper, we propose destination-specific MRTs (dMRTs), an improved variant of MRTs, for protection of IP networks. This mechanism reduces the generated path lengths but increases the computational complexity of the MRT algorithm. We analyze and compare our proposal with simple MRTs and MPLS FRR. We show on a large and publicly available network data base that dMRTs provide significant shorter backup paths compared to simple MRTs and require less forwarding state and network capacities than MPLS FRR. Adapting an existing FRR mechanism for IP networks to SDN enables its deployment in hybrid-SDN networks. Thus, we outline implementation options of dMRTs in IP and MPLS networks and (d)MRTs in SDN. Finally, we discuss the computational overhead of our proposal in the context of (decentralized) IP networks and (centralized) SDNs.

Background For patients (pts) with advanced or metastatic renal cell carcinoma (mRCC), approval of novel therapies led to continuous changes in treatment options. The Tumour Registry Renal Cell Carcinoma (TNK) analysed treatment and outcome of pts treated in Germany from 2007-2017. CARAT is the successor registry, which continues to assess longitudinal real world clinical outcome, incl. patient-reported outcomes (PROs) and decentralized biobanking. Today, we introduce CARAT and report on current changes of the treatment landscape in mRCC in Germany. Methods Since Dec 2017 150 pts have been enrolled in CARAT, expanding the previous TNK (2007-17, 1500 pts). CARAT is an observational, prospective, open, multicentre clinical research platform aiming to enrol 1000 pts by 150 sites. Pts with mRCC who start systemic 1stline treatment are eligible. Treatment characteristics, clinical outcome and physician-reported factors on treatment decision making are collected. Overall survival (OS) is assessed by the KM-method. Changes of the treatment landscape are shown descriptively. Results By April 2019 >1650 pts with mRCC have been recruited. Median age is 68 years. 60% had intermediate risk (MSKCC) at start of 1st-line. Median OS for pts with start of 1st-line 2007-17 is 19 months (>60% events). If selected by trial eligibility criteria, the median OS is 27 months. Pts who started treatment in 2018 mostly received pazopanib or sunitinib (38%/34%). Since the approval (May 2018) 18% are treated with cabozantinib. Preferred 2nd-line treatment changed from sorafenib/temsirolimus (35%/21%, 2007-09), everolimus (33% 2010-12), everolimus/axitinib/sunitinib (29%/19%/18%, 2013-15) to nivolumab (>60% since 2016). The impact of new treatment options on OS will be analysed. Conclusions Pts in routine care in Germany are older and have inferior prognosis than trial-eligible pts. CARAT complements results of RCTs with prospective data on clinical and PROs for pts with mRCC in routine care. CARAT will show changes in the choice of treatment due to new approvals, applied sequences and investigate the effectiveness in a “real world” setting. For the first time, these data will be combined with PROs and a decentralized biobank for translational research. Legal entity responsible for the study IOMEDICO. Funding Ipsen. Disclosure P.J. Goebell: Honoraria (self), Advisory / Consultancy: Amgen; Honoraria (self), Advisory / Consultancy: Astellas; Honoraria (self), Advisory / Consultancy: AstraZeneca; Honoraria (self), Advisory / Consultancy: Bayer; Honoraria (self), Advisory / Consultancy: BMS; Honoraria (self), Advisory / Consultancy: Eisai; Honoraria (self), Advisory / Consultancy: Ipsen; Honoraria (self), Advisory / Consultancy: Janssen; Honoraria (self), Advisory / Consultancy: MSD; Honoraria (self), Advisory / Consultancy: Novartis; Honoraria (self), Advisory / Consultancy: Pfizer; Honoraria (self), Advisory / Consultancy: Sanofi; Honoraria (self): IOMEDICO. M. Bogemann: Honoraria (self), Advisory / Consultancy, Research grant / Funding (self): Janssen; Honoraria (self), Advisory / Consultancy, Research grant / Funding (self): Astellas; Honoraria (self), Advisory / Consultancy: Novartis; Honoraria (self), Advisory / Consultancy: Pfizer; Honoraria (self), Advisory / Consultancy, Research grant / Funding (self): Ipsen; Honoraria (self), Advisory / Consultancy: BMS; Honoraria (self), Advisory / Consultancy: MSD; Honoraria (self), Advisory / Consultancy: Eisai; Honoraria (self), Advisory / Consultancy: Bayer; Honoraria (self), Advisory / Consultancy: Eusa Pharma; Honoraria (self), Advisory / Consultancy: ABX; Honoraria (self), Advisory / Consultancy: Sanofi; Honoraria (self), Advisory / Consultancy: AstraZeneca; Honoraria (self), Advisory / Consultancy: Amgen. S. Dorfel: Shareholder / Stockholder / Stock options: IOMEDICO. N.W. Marschner: Advisory / Consultancy, Leadership role, Research grant / Funding (institution), Shareholder / Stockholder / Stock options: IOMEDICO; Research grant / Funding (institution): Pfizer; Research grant / Funding (institution): Novartis; Research grant / Funding (institution): Ipsen. M. Staehler: Honoraria (self), Advisory / Consultancy, Research grant / Funding (self): Pfizer; Honoraria (self), Advisory / Consultancy, Research grant / Funding (self): Bayer; Honoraria (self), Advisory / Consultancy, Research grant / Funding (self): Novartis; Honoraria (self), Advisory / Consultancy, Research grant / Funding (self): GSK; Honoraria (self), Advisory / Consultancy, Research grant / Funding (self): Roche. V. Grunwald: Honoraria (self), Research grant / Funding (self), Shareholder / Stockholder / Stock options, Non-remunerated activity/ies: MSD; Research grant / Funding (self): Novartis; Honoraria (self), Research grant / Funding (self), Shareholder / Stockholder / Stock options: AstraZeneca; Honoraria (self), Research grant / Funding (self), Shareholder / Stockholder / Stock options, Non-remunerated activity/ies: BMS; Honoraria (self), Non-remunerated activity/ies: Merck Serono; Honoraria (self): Roche; Honoraria (self): Pfizer; Honoraria (self): Lilly; Honoraria (self), Non-remunerated activity/ies: PharmaMar; Honoraria (self): Nanobiotix; Honoraria (self): Janssen. All other authors have declared no conflicts of interest.

Oncotype DX testing is reimbursed in Israel for node-negative and node-positive (N1+; up to 3 positive nodes including micrometastases), estrogen receptor positive (ER+), breast cancer patients. This retrospective study evaluated the impact of Oncotype DX testing on treatment decisions in N1+/ER+ breast cancer patients. To this end, we compared treatments for all N+ patients for whom testing had been ordered with treatments for patients with similar characteristics where the test had not been available. The retrospective analysis included 951 patients (282 Oncotype DX, 669 controls), all of whom received endocrine therapy with or without chemotherapy. In Oncotype DX patients, 7.1, 37.0, and 100 % of those with low, intermediate, and high Recurrence Score results (Oncotype DX summary score) received chemotherapy, respectively (P

Cardiovascular disease is the leading cause of death, and the role of occupation continues to generate interest. Using the National Occupational Mortality Surveillance system, proportionate mortality ratio (PMR) analyses were used to examine the association between occupation and ischemic heart disease among 16- to 60-year-old males. We used data from 1982-1992 from 27 states. Separate analyses were conducted for blue-collar and white-collar occupations. Among the blue-collar occupations with the highest PMRs for ischemic heart disease mortality were sheriffs, correctional institution officers, policemen, firefighters, and machine operators. Physicians (blacks only) and clergy (both races) were among the white-collar occupations with the highest PMRs for ischemic heart disease. Although more study is needed, consideration should be made for targeting high-PMR occupations, with improvement in work organization to reduce occupational stress and promotion of healthy lifestyles through cardiovascular disease prevention programs.

e22111 Background: The Oncotype DX Colon Cancer Recurrence Score (RS) is a validated prognosticator in stage II colon cancer following surgery. However, the impact of the RS on daily practice is still unclear. Clalit Health Services(CHS) has reimbursed Oncotype DX colon testing since 1/2011. This prospective study examined the use of the RS and its association with treatment decisions in this setting in Israel. Methods: Eligible patients had stage II colon cancer and testing reimbursed by CHS from 1/2011 to 5/2012. Patient/tumor data and treatment information were gathered prospectively. Data were analyzed using the Chi-squared test. Results: The study included 341 patients of whom 314 had confirmed stage II, T3N0 disease, and were included in the analysis. Median age was 68 years (range: 29-89); 18.2%, 68.5%, and 9.9% had grade 1, 2, and 3 tumors, respectively; 15.3% had colonic obstruction and 5.7% had lymphovascular invasion. Thirty-nine patients (12.4%) had mismatch repair (MMR)-deficient tumors and their samples were not tested further. Of the 275 tested patients, 160 (58.2%), 87 (31.6%), and 27 (9.8%) had low (40) RS, respectively (1 patient [0.4%] had no RS due to technical failure of the assay). The grade 3 group had a higher proportion of MMR-deficient tumors than the grade 2 and grade 1 groups (35.5%, 7.9% and 10.5%, respectively, P

6075 Background: Recent Oncotype DX studies indicate that the recurrence score (RS) can identify certain N+/ER+ patients who may not benefit from chemotherapy. Clalit Health Services, Israel, was the first HMO outside the United States to reimburse the assay, and the RS has been used for treatment planning in N+/ER+ patients. We evaluated the relationship of the RS and actual adjuvant chemotherapy treatment in ER+ N+ patients. Methods: Eligible patients with micrometastases, 1, 2, 3, or 4 positive lymph nodes were identified between March 2006 and September, 2009. Claims data were reviewed to identify actual treatment administered. Results: 260 patients were eligible. 126 (48%) had micrometastases, 92 (35%) had 1 node, 36 (14%) had 2 nodes, 5 (2%) had three nodes, and 1 (

Despite the significant advancement in HIV/AIDS treatment with highly active antiretroviral therapy (HAART), HIV/AIDS remains incurable. Limitations of HAART include expense, disabling complications, and a stringent requirement for compliance. In the United States, where HAART has become the standard of care, approximately 20% of newly transmitted virus is already resistant to at least one antiretroviral drug. In anticipation of expanded HAART in Africa, there is concern regarding rapid emergence of drug resistant strains of HIV that brings into question HAART as a long-term solution. We have developed an alternative therapy for HIV/AIDS therapy using an HIV-1-based lentiviral vector expressing a 937-base antisense gene against the HIV envelope, VRX496, for autologous T cell therapy. T cells are transduced with vector in the presence of co-stimulatory CD3/CD28 beads, and subsequently expanded in culture. Preclinical studies demonstrated the feasibility of this approach in normal CD4+ T cells and inCD4+ T cells isolated from 20 early and late stage patients, as defined by viral loads. An efficient gene transfer procedure was established, which demonstrated stable transfer rates of 94% +/- 5%. Antisense inhibited HIV in cultures by >93% over mock transduced controls, regardless of patient status or the tropism of the infecting virus. A Phase I open label non-randomized clinical trial was then initiated to investigate the safety and tolerability of autologous T cells modified with VRX496. In this study, 5 HAART resistant patients having CD4 T cells counts between 200-500 cells/mm3 are serially enrolled in the study that includes 3-week, and 3 and 6-month monitoring points. Each patient is given approximately 1 1010 modified autologous CD4 T cells in a single dose. Patients are monitored for viral load, CD4 count, emergence of any replication competent lentivirus (RCL), immunological parameters, and clinical indications. Adverse events are defined in part by a sustained 0.5 log increase in viral load, or sustained 0.5 log decrease in CD4 count within 3 weeks post dose. To date, 3 subjects have been infused, and the first and second subjects have completed the 6 and 3-month monitoring points, respectively. No adverse events have been noted, and all RCL assays have been negative. CD4 counts remained steady and engraftment of VRX496-modified cells was observed for at least 6 months in the first patient and 3 months in the second patient. At dosing, subject 1 had an average viral load of 188,500 and subject 2 had an average viral load of 40,428. After three and six months post dosing, subjects 1 and 2 respectively, had viral loads below baseline. This interim analysis supports the promise of lentiviral vectors for late stage HIV infection, and that VRX496 could become a viable treatment modality for individuals infected with HIV/AIDS.

This study examines shifts in the relationship between the Brooklyn Family Court and Kings County Hospital, a child-adolescent municipal psychiatric hospital. It focuses on the 4,532 psychiatric admissions during three periods (1960–1962, 1972–1974, and 1975–1977), which represent periods of historical change in the relationship between the Family Courts and municipal psychiatric hospitals. A comparison of the admissions during these periods indicates that the addition of a large mental health screening staff in the courts (1972–1974) and increased mental health facilities in Brooklyn (1975–1977) led to a significant decrease in the hospitalization of social rather than psychiatric emergencies that resulted in a major improvement in the care that could be given to the psychiatric emergencies.

SYNOPSIS. In order to observe a specimen at high magnifications in the electron-microscope whilst keeping the instrumental magnification and intensity low, an optical magnifier is used to observe the image on the fluorescent screen. The brightness of the fluorescent screen at various instrumental magnifications and in combination with several optical magnifications is given in a table. A second table shows how the latitude encountered in the electron-microscope when determining “sharp focus” is compressed by using the optical binocular magnifier at increasing magnifications. When observing finest details at the highest magnifications and taking photographs with the electron-microscope the findings of the “sharpest focus” with the aid of the binocular magnifier results in the highest resolution becoming both visible and recordable. So far a resolution better than 25° has been obtained. The combination of the highly efficient zinc-cadmium-sulphide screen with the binocular magnifier is applied to the study of bacteriophage of Bacterium coli. A number of photographs show the sharpness obtained with the help of this combination and it is possible to follow the mechanism of bacteriophage action and behaviour in finest detail: the moment of entry of one ‘phage body into the bacterial cell, beginning and end stages in the multiplication of bacteriophage, colony formation, and the reaction of bacterial protoplasm during and after lysis.

When working with bacteria, bacteriophages and viruses, the limits, first of resolution and then of visibility, were approached. Examples showed how resolution was increased by increasing the numerical aperture (N.A.) and the refractive index. Internal structures, involution granules and spores in dried not-fixed bacteria, bacteriophages from B. coli and staphylococci can be resolved in this way. A method of azimuthal illumination was shown to give similar results with active cells. Further, a method was described in which resolution was obtained by reduction of intensity; the reduction was effected by crossing polaroid discs or by interposing neutral grey filters. This method of increased resolution by decreased intensity was illustrated by a number of photographs showing the separation of otherwise inseparable holes in a screen, the resolution of the shape of otherwise unresolved holes and the application of this method to viruses. In this way the slit between diplococci could be resolved after highest N.A. and n had not rendered it resolvable. The elementary bodies of certain viruses were separated and their shapes resolved. This method has been applied successfully to the measurement of the sizes of virus bodies. The measurements were checked and confirmed with a microphotometer built on the artificial star principle. Most of the results were recorded photographically as well as observed visually, showing that the effect of increased resolution by reduced intensity can be produced if the eye is the perceptive instrument or if the photographic emulsion is employed for the purpose. The medium of reception, whether retina or emulsion grain, imposes its modifications on the effect, which was realized with a number of different optical systems by various makers. To sum up, it appeared in the course of the experiments described that all ways of increasing resolution must lead to the same effect, that is the reduction of the diameter of the Airy disc or diffraction fringe. Whether this is done by increasing the N.A. or n, or decreasing the wave-length or the intensity, the result must be in the same direction. The factors N.A., n and λ are represented in the formula for resolution, and it was suggested that intensity should be included.

THE diffraction of light on a circular aperture in a thin opaque screen has been studied by G. B. Airy1, E. Lommel2 and many others after them. The experiment is of fundamental importance for the theory of the image formation in optical instruments. The formula given by Airy has been but little modified, and in its present form (Preston3) is: where X is the minimum separable distance between two neighbouring disks, representing points of the object, the wave-length of the light, F the focal length and d the diameter of the lens.