287 research outputs found

    Adapt then Unlearn: Exploiting Parameter Space Semantics for Unlearning in Generative Adversarial Networks

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    The increased attention to regulating the outputs of deep generative models, driven by growing concerns about privacy and regulatory compliance, has highlighted the need for effective control over these models. This necessity arises from instances where generative models produce outputs containing undesirable, offensive, or potentially harmful content. To tackle this challenge, the concept of machine unlearning has emerged, aiming to forget specific learned information or to erase the influence of undesired data subsets from a trained model. The objective of this work is to prevent the generation of outputs containing undesired features from a pre-trained GAN where the underlying training data set is inaccessible. Our approach is inspired by a crucial observation: the parameter space of GANs exhibits meaningful directions that can be leveraged to suppress specific undesired features. However, such directions usually result in the degradation of the quality of generated samples. Our proposed method, known as 'Adapt-then-Unlearn,' excels at unlearning such undesirable features while also maintaining the quality of generated samples. This method unfolds in two stages: in the initial stage, we adapt the pre-trained GAN using negative samples provided by the user, while in the subsequent stage, we focus on unlearning the undesired feature. During the latter phase, we train the pre-trained GAN using positive samples, incorporating a repulsion regularizer. This regularizer encourages the model's parameters to be away from the parameters associated with the adapted model from the first stage while also maintaining the quality of generated samples. To the best of our knowledge, our approach stands as first method addressing unlearning in GANs. We validate the effectiveness of our method through comprehensive experiments.Comment: 15 pages, 12 figure

    Warm tachyonic inflation in warped background

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    We analyze warm tachyonic inflation, proposed in the literature, but from the viewpoint of four dimensional effective action for tachyon field on a non-BPS D3-brane. We find that consistency with observational data on density perturbation and validity of effective action requires warped compactification. The number of background branes which source the flux is found to be of the order of 10 in contrast to the order of 101410^{14} in the standard cold inflationary scenario.Comment: 9 pages, RevTe

    Sister chromatid exchange in peripheral blood lymphocytes as a possible breast cancer risk biomarker: A study of Iranian patients with breast cancer

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    Introduction: Sister chromatid exchanges (SCEs) can be induced by variousgenotoxic treatments, suggesting that SCEs refl ect a DNA repair process and it may be a good index for assessment of genomic instability. However, the occurrence of genetic instability and in particular, of spontaneous SCEs has been strongly linked to cancer. Several chromosomal regions and many genes have been implicated in breast cancer.Materials and Methods: Blood samples were obtained from 31 Iranian breast cancer patients and 11 healthy women. SCE was measured in peripheral blood lymphocytes by adding to Ham’sF10 medium in presence of PHA, BrdU (5-bromo-deoxy Uridine) fl uorochrome Hoechst 33258, exposure to UV light and Giemsa staining. Then, SCE frequencies of patient and control groups were compared by the Mann-Withney U-test.Results: Signifi cantly difference was observed between two groups (

    DEVELOPING ANDROID APPLICATION ASSISTED BY ANDROMO FOR SOLAR SYSTEM LEARNING

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    ABSTRAK   Pesatnya perkembangan teknologi informasi salah satunya dipengaruhi oleh perkembangan teknologi dan handphone yang semakin maju, sehingga dapat dikatakan perkembangan keduanya sangatlah erat dan berjalan beriringan. Multimedia merupakan gabungan beberapa komponen seperti teks, audio, video, animasi, dan gambar yang berguna untuk menunjang proses pembelajaran, karena visualisasi dalam bentuk animasi sangat diperlukan untuk materi yang disampaikan oleh guru. Tujuan dari penelitian ini adalah mengembangkan produk aplikasi android dan untuk mengetahui penilaian terhadap produk yang telah dihasilkan oleh peneliti dan peneliti dapat mengetahui respon produk kepada siswa. Hasil penilaian yang dilakukan responden terhadap produk yang dihasilkan peneliti adalah produk yang dihasilkan sangat baik, hal ini dibuktikan dengan total skor rata-rata sebesar 20 dengan keterangan produk yang dihasilkan sangat baik dimana produk tersebut dinilai dari beberapa aspek, termasuk kemudahan penggunaan, presentasi, keterbacaan dan peran multimedia.   Kata kunci:  Multimedia, Andromo, IPA   ABSTRACT   The rapid advancement of information technology, heavily influenced by the ever-advancing mobile phone technology, has led to a closely intertwined development of the two. Multimedia, comprising components such as text, audio, video, animation, and images, plays a vital role in supporting the learning process. This is especially important because visual aids, in the form of animations, are essential for conveying instructional material. The primary aim of this study is to evaluate the products created by the researchers. The significance of this research lies in enabling the researchers to identify areas for improvement in the multimedia products they have developed. The assessment conducted by respondents on the researcher-produced products yielded highly positive results, with an average score of 20. These results confirm the products' excellence, with evaluations encompassing factors like user-friendliness, presentation, readability, and the multimedia's overall contribution to the learning experience.   keywords, Multimedia, Andromo, IP

    A study of bone marrow angiogenesis and its correlation with serum vascular endothelial growth factor levels in acute leukaemia

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    Background: Angiogenesis, which is the development of new capillaries from existing blood vessels, occurs in both the developing embryo and postnatal life. The growth of solid tumours requires the development of micro vessels; therefore, tumour expansion correlates with the extent of angiogenesis.Methods: A prospective study was conducted on bone marrow trephine biopsies of 40 new cases of acute leukaemia diagnosed on complete blood count, bone marrow aspiration examination, and flow cytometry, including 20 control cases. Micro sections were stained with immuno-histochemical stains using monoclonal antibodies to CD31, CD34 and vWF. Micro vessel density was analysed at a 400× using automated image analyser by two investigators independently. Data were calculated, tabulated and statistically analysed using statistical package for the social sciences (SPSS) statistical program version 18.Results: A total of 1522 micro vessels were analysed using CD31 including 802 in acute myeloid leukaemia (AML), 512 in acute lymphocytic leukemia (ALL) and 208 in the control group. The bone marrow microvessel density (MVD) in acute myeloid leukaemia using CD31, CD34 and Von Willebrand factor (VWF) was 70.83±20.76, 66.48±18.99 and 60.32±18.75 respectively while MVD in acute lymphoblastic leukaemia was 62.74±21.09, 70.58±22.46 and 51.22±21.13 respectively. The study revealed significant difference between AML, ALL and normal bone marrow cases by using CD31, CD34 and vWF antibody. Serum vascular endothelial growth factor (VEGF) concentration in AML, ALL and control group was 163.74±119.03, 168.23±154.22 and 43.45±9.14 respectively.Conclusions: Higher micro vessel density was observed in acute leukaemia. Present findings suggested the potential significance of characteristics of micro vessel density as potential prognostic marker as well as its application in improved selection of patients for anti-angiogenic and other treatments

    Universal Scaling of Wave Propagation Failure in Arrays of Coupled Nonlinear Cells

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    We study the onset of the propagation failure of wave fronts in systems of coupled cells. We introduce a new method to analyze the scaling of the critical external field at which fronts cease to propagate, as a function of intercellular coupling. We find the universal scaling of the field throughout the range of couplings, and show that the field becomes exponentially small for large couplings. Our method is generic and applicable to a wide class of cellular dynamics in chemical, biological, and engineering systems. We confirm our results by direct numerical simulations.Comment: 4 pages, 3 figures, RevTe

    Mutation analysis of BRCA1 and BRCA2 genes in Iranian high risk breast cancer families

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    Background: Telomerase is a ribonucleoprotein enzyme that synthesises telomeres after cell division and maintains chromosomal stability leading to cellular immortalization. Telomerase has been associated with negative prognostic indicators in some studies. The present study aims to detect any association between telomerase sub-units: hTERT and hTR and the prognostic indicators including tumour's size and grade, nodal status and patient's age. Methods: Tumour samples from 46 patients with primary invasive breast cancer and 3 patients with benign tumours were collected. RT-PCR analysis was used for the detection of hTR, hTERT, and PGM1 (as a housekeeping) genes expression. Results: The expression of hTR and hTERT was found in 31(67.4%) and 38 (82.6%) samples respectively. We observed a significant association between hTR gene expression and younger age at diagnosis (p = 0.019) when comparing patients ≤ 40 years with those who are older than 40 years. None of the benign tumours expressed hTR gene. However, the expression of hTERT gene was revealed in 2 samples. No significant association between hTR and hTERT expression and tumour's grade, stage and nodal status was seen. Conclusion: The expression of hTR and hTERT seems to be independent of tumour's stage. hTR expression probably plays a greater role in mammary tumourogenesis in younger women (≤ 40 years) and this may have therapeutic implications in the context of hTR targeting strategies

    Using circular dichroism to control energy transfer in multi-photon ionization

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    Chirality causes symmetry breaks in a large variety of natural phenomena ranging from particle physics to biochemistry. We investigate one of the simplest conceivable chiral systems, a laser-excited, oriented, effective one-electron Li target. Prepared in a polarized p state with |m|=1 in an optical trap, the atoms are exposed to co- and counter-rotating circularly polarized femtosecond laser pulses. For a field frequency near the excitation energy of the oriented initial state, a strong circular dichroism is observed and the photoelectron energies are significantly affected by the helicity-dependent Autler-Townes splitting. Besides its fundamental relevance, this system is suited to create spin-polarized electron pulses with a reversible switch on a femtosecond timescale at an energy resolution of a few meV
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