Invariant variational principle for Hamiltonian mechanics

It is shown that the action for Hamiltonian equations of motion can be brought into invariant symplectic form. In other words, it can be formulated directly in terms of the symplectic structure $\omega$ without any need to choose some 1-form $\gamma$, such that $\omega= d \gamma$, which is not unique and does not even generally exist in a global sense.Comment: final version; to appear in J.Phys.A; 17 pages, 2 figure

Improved metrological software test for temperature measurements

Запропоновано структуру вдосконаленого метрологічного програмного тесту шляхом введення в його структуру нових блоків, що дають змогу враховувати вплив специфічних похибок термоелектричного перетворювача з керованим профілем температурного поля. В такому вигляді він стає придатним для імітації вимірювального каналу, який використовує ТЕП з КПТП і створює можливість дослідження метрологічних характеристик такого вимірювального каналу. Крім того, наведено результати досліджень і дано рекомендації щодо подальшого зменшення похибки вимірювання температури.Modern measuring channels of measurement and control systems become more complex. This complicates the process of determining metrological characteristics of such systems due to the rapid growth of the amount of experimental investigations. Nowadays the model simulation is often used to solve this problem [1 ... 3] and allows to speed up the metrological investigations. There was suggested the creation of specialized software – metrological software tests (MST) [4, 5]. MST contains blanks simulation models of typical components of measuring channels. These models contain specific errors of relevant components of the system units. They take into account the mentioned above errors effect on measurement results during modeling process. The signal is sent to the corresponding input of MST component. It makes possible the investigation of considered set of components reaction on the corresponding errors and estimate efficiency of the available in the measuring channel means of decreasing of those errors. Thus, the MST allows investigation of the efficiency of methods and means of correcting errors for different conditions and environments. Available MST allows to investigate only measuring channels, in which the error from the acquired thermoelectric heterogeneity of thermocouples is adjusted according to the method considered in [7, 8]. That is why MST should be appropriately modified. The aim of the proposed paper is to improve the MST described in [4, 5] to be able to apply improved MPT for investigations of the measuring channel that use TBS with CPTF. The structure of the proposed MST measuring channel of temperature measurements that uses TBS with CPTF is presented in Fig. 1. The MST similar to the MST is considered to be described in [4 ... 6], the same additive error model of measuring channel components. The structure of the measuring channel itself and digital to analog converters that can directly interact with components of the measuring channel is shown in the top of Fig. 1. The most important part of the MST is the sets forming software located in the middle of Fig. 1. Each MST block simulates only one property of a component of the measuring channel then blocks are grouped by components ( below each component of the measuring channel of the top part of Fig. 1 "its own" blocks of MST). The blocks that simulate main error are located in the top row. These errors are split into components. Additional errors caused by the temperature and time of exploitation are located below. The errors caused by the additional parameters are located in the next row. The only difference is that additional block – block of thermoelectric heterogeneity is built-in structure of conventional MST. If any error consists of separate components, these components are placed below it. The lowest row are blocks of nominal conversion characteristic (CC) of components. The thermocouple is split into two subcomponents (hot and cold junctions). CC of switch is considered to be equal to one. However, the profile of temperature field of the main thermocouple TBS with CPTF is not constantly stable. It changes under influence of: 1. Non ideal design of TBS with CPTF. 2. Errors of built-in multi-channel temperature control subsystem, which supports and stabilizes the profile of the temperature field along main thermocouple of TBS with CPTF. The structure of MST for research of measuring channel that use TBS with CPTF as it was shown in [4, 5], MST consist of three relatively independent units: 1. Software for creating sets of test signals (codes). These codes correspond to output signals of components of the measuring channel, whose work is simulated by MST; 2. Software for providing communication with considered measuring channel that delivers the generated set of test signals to the inputs of the respective components, and also receives and stores the measurement; 3. Software for processing the results obtained during the investigations

Characterising Australian memory clinics: current practice and service needs informing national service guidelines

Background: Memory clinics (MCs) play a key role in accurate and timely diagnoses and treatment of dementia and mild cognitive impairment. However, within Australia, there are little data available on current practices in MCs, which hinder international comparisons for best practice, harmonisation efforts and national coordination. Here, we aimed to characterise current service profiles of Australian MCs. Methods: The ‘Australian Dementia Network Survey of Expert Opinion on Best Practice and the Current Clinical Landscape’ was conducted between August-September 2020 as part of a larger-scale Delphi process deployed to develop national MC guidelines. In this study, we report on the subset of questions pertaining to current practice including wait-times and post-diagnostic care. Results: Responses were received from 100 health professionals representing 60 separate clinics (45 public, 11 private, and 4 university/research clinics). The majority of participants were from clinics in metropolitan areas (79%) and in general were from high socioeconomic areas. While wait-times varied, only 28.3% of clinics were able to offer an appointment within 1-2 weeks for urgent referrals, with significantly more private clinics (58.3%) compared to public clinics (19.5%) being able to do so. Wait-times were less than 8 weeks for 34.5% of non-urgent referrals. Only 20.0 and 30.9% of clinics provided cognitive interventions or post-diagnostic support respectively, with 7.3% offering home-based reablement programs, and only 12.7% offering access to group-based education. Metropolitan clinics utilised neuropsychological assessments for a broader range of cases and were more likely to offer clinical trials and access to research opportunities. Conclusions: In comparison to similar countries with comprehensive government-funded public healthcare systems (i.e., United Kingdom, Ireland and Canada), wait-times for Australian MCs are long, and post-diagnostic support or evidence-based strategies targeting cognition are not common practice. The timely and important results of this study highlight a need for Australian MCs to adopt a more holistic service of multidisciplinary assessment and post-diagnostic support, as well as the need for the number of Australian MCs to be increased to match the rising number of dementia cases

Formation of Giant Quasibound Cold Diatoms by Strong Atom-Cavity Coupling

We show that giant quasi-bound diatomic complexes, whose size is typically hundreds of nm, can be formed by intra-cavity cold diatom photoassociation or photodissociation in the strong atom-cavity coupling regime.Comment: 4 pages, 3 figure

Gate-tunable black phosphorus spin valve with nanosecond spin lifetimes

Two-dimensional materials offer new opportunities for both fundamental science and technological applications, by exploiting the electron spin. While graphene is very promising for spin communication due to its extraordinary electron mobility, the lack of a band gap restricts its prospects for semiconducting spin devices such as spin diodes and bipolar spin transistors. The recent emergence of 2D semiconductors could help overcome this basic challenge. In this letter we report the first important step towards making 2D semiconductor spin devices. We have fabricated a spin valve based on ultra-thin (5 nm) semiconducting black phosphorus (bP), and established fundamental spin properties of this spin channel material which supports all electrical spin injection, transport, precession and detection up to room temperature (RT). Inserting a few layers of boron nitride between the ferromagnetic electrodes and bP alleviates the notorious conductivity mismatch problem and allows efficient electrical spin injection into an n-type bP. In the non-local spin valve geometry we measure Hanle spin precession and observe spin relaxation times as high as 4 ns, with spin relaxation lengths exceeding 6 um. Our experimental results are in a very good agreement with first-principles calculations and demonstrate that Elliott-Yafet spin relaxation mechanism is dominant. We also demonstrate that spin transport in ultra-thin bP depends strongly on the charge carrier concentration, and can be manipulated by the electric field effect

PDL1 Signals through Conserved Sequence Motifs to Overcome Interferon-Mediated Cytotoxicity

PDL1 blockade produces remarkable clinical responses, thought to occur by T cell reactivation through prevention of PDL1-PD1 T cell inhibitory interactions. Here, we find that PDL1 cell-intrinsic signaling protects cancer cells from interferon (IFN) cytotoxicity and accelerates tumor progression. PDL1 inhibited IFN signal transduction through a conserved class of sequence motifs that mediate crosstalk with IFN signaling. Abrogation of PDL1 expression or antibody-mediated PDL1 blockade strongly sensitized cancer cells to IFN cytotoxicity through a STAT3/caspase-7-dependent pathway. Moreover, somatic mutations found in human carcinomas within these PDL1 sequence motifs disrupted motif regulation, resulting in PDL1 molecules with enhanced protective activities from type I and type II IFN cytotoxicity. Overall, our results reveal a mode of action of PDL1 in cancer cells as a first line of defense against IFN cytotoxicity

Generation of a wave packet tailored to efficient free space excitation of a single atom

We demonstrate the generation of an optical dipole wave suitable for the process of efficiently coupling single quanta of light and matter in free space. We employ a parabolic mirror for the conversion of a transverse beam mode to a focused dipole wave and show the required spatial and temporal shaping of the mode incident onto the mirror. The results include a proof of principle correction of the parabolic mirror's aberrations. For the application of exciting an atom with a single photon pulse we demonstrate the creation of a suitable temporal pulse envelope. We infer coupling strengths of 89% and success probabilities of up to 87% for the application of exciting a single atom for the current experimental parameters.Comment: to be published in Europ. Phys. J.

The Promise and Perils of Private Voluntary Regulation: Labor Standards and Work Organization in Two Mexican Garment Factories

This paper is part of a larger project on globalization and labor standards organized by Professor Richard Locke of M.I.T.. In addition to the results presented in this paper (some of which appear as well in Monica Romis, "Beneath Corporate Codes of Conduct: What Drives Compliance in Two Mexican Garment Factories," (Masters Thesis, Dept. of Urban Studies and Planning, M.I.T., 2005)), the project entailed field research in China, Turkey, Europe and the United States as well as systematic analysis of Nike’s factory audits of working conditions in over 800 factories in 51 countries.What role can private voluntary regulation play in improving labor standards and working conditions in global supply chain factories? How does this system relate to and interact with other systems of labor regulation and work organization? This paper seeks to address these questions through a structured comparison of two factories supplying Nike, the world’s largest athletic footwear and apparel company. These two factories have many similarities - both are in Mexico, both are in the apparel industry, both produce more or less the same products for Nike (and other brands) and both are subject to the same code of conduct. On the surface, both factories appear to have similar employment (i.e., recruitment, training, remuneration) practices and they receive comparable scores when audited by Nike’s compliance staff. However, underlying (and somewhat obscured by) these apparent similarities, significant differences in actual labor conditions exist between these two factories. What drives these differences in working conditions? What does this imply for traditional systems of monitoring and codes of conduct? Field research conducted at these two factories reveals that beneath the code of conduct and various monitoring efforts aimed at enforcing it, workplace conditions and labor standards are shaped by very different patterns of work organization and human resource management policies

Associations between reaction time measures and white matter hyperintensities in very old age.

In old age, a relationship has been reported between intraindividual variability (IIV) in reaction time and white matter integrity as evidenced by white matter hyperintensities (WMH). However, it is unclear how far such associations are due to incipient neurodegenerative pathology in the samples investigated. The present study examined the relationship between IIV and WMH in older individuals (N=526) drawn from the Sydney Memory and Ageing Study. Using a complex reaction time (RT) task, greater IIV and mean-RT were related to a higher WMH burden in the frontal lobe. Critically, significant associations remained having taken future dementia into account suggesting that they were not explained by incipient dementia. Additionally, independent measures of executive function accounted for the association between RT metrics and WHM. The results are consistent with the view that frontally-supported cognitive processes are involved in IIV-WMH relations, and that RT measures are sensitive to compromise in white matter structures in non-demented older individuals