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  1. Book ; Online: Infusing Lattice Symmetry Priors in Attention Mechanisms for Sample-Efficient Abstract Geometric Reasoning

    Atzeni, Mattia / Sachan, Mrinmaya / Loukas, Andreas

    2023  

    Abstract: The Abstraction and Reasoning Corpus (ARC) (Chollet, 2019) and its most recent language-complete instantiation (LARC) has been postulated as an important step towards general AI. Yet, even state-of-the-art machine learning models struggle to achieve ... ...

    Abstract The Abstraction and Reasoning Corpus (ARC) (Chollet, 2019) and its most recent language-complete instantiation (LARC) has been postulated as an important step towards general AI. Yet, even state-of-the-art machine learning models struggle to achieve meaningful performance on these problems, falling behind non-learning based approaches. We argue that solving these tasks requires extreme generalization that can only be achieved by proper accounting for core knowledge priors. As a step towards this goal, we focus on geometry priors and introduce LatFormer, a model that incorporates lattice symmetry priors in attention masks. We show that, for any transformation of the hypercubic lattice, there exists a binary attention mask that implements that group action. Hence, our study motivates a modification to the standard attention mechanism, where attention weights are scaled using soft masks generated by a convolutional network. Experiments on synthetic geometric reasoning show that LatFormer requires 2 orders of magnitude fewer data than standard attention and transformers. Moreover, our results on ARC and LARC tasks that incorporate geometric priors provide preliminary evidence that these complex datasets do not lie out of the reach of deep learning models.

    Comment: Accepted for publication at the International Conference on Machine Learning, ICML 2023
    Keywords Computer Science - Artificial Intelligence ; Computer Science - Machine Learning ; Statistics - Machine Learning
    Subject code 006
    Publishing date 2023-06-05
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Article ; Online: The profunda artery perforator flap for upper limb reconstruction: A case report and literature review on the flap applications in reconstruction.

    Boriani, Filippo / Sassu, Paolo / Atzeni, Matteo / Buckley, Christina / Figus, Andrea

    Microsurgery

    2022  Volume 42, Issue 7, Page(s) 714–721

    Abstract: The profunda femoris artery perforator (PAP) flap has been recently popularized as an alternative option for microsurgical reconstruction. The use of PAP flap has never been reported and described for reconstruction of the upper extremities, in ... ...

    Abstract The profunda femoris artery perforator (PAP) flap has been recently popularized as an alternative option for microsurgical reconstruction. The use of PAP flap has never been reported and described for reconstruction of the upper extremities, in particular the forearm. The purpose of this case report is to describe a case suggesting the PAP flap as a further reconstructive option in the upper limb. A 16-year-old girl who sustained a traumatic injury to her right dominant forearm resulting in subtotal circumferential tissue loss following a road traffic accident was referred to the authors' department 2 years post-trauma. The disabling fibrotic sequelae on her volar forearm (15 × 10 cm) resulted in a nonfunctional hand. She was unable to perform any active movement of her wrist or digits. Passive movements in the finger joints were preserved. Following debridement and reconstruction of nerves and tendons, soft tissues were resurfaced with a PAP flap. The transverse skin paddle, 12 × 7 cm, was placed distally with the adipofascial portion positioned proximally above the muscle bellies and anastomoses site. A small raw area (4 × 3 cm) was covered with an acellular dermal matrix (ADM). The postoperative course was uneventful. At 9 months postoperatively, the patient demonstrated active flexion and extension of the fingers with independent function. The patient reported satisfaction with the flap donor site and forearm resurfacing. The PAP flap can be a further option for areas requiring soft tissue coverage in patients refusing visible scars. This flap had both the advantage of reducing the morbidity and visibility of the donor site, as well as the ability to resurface a large recipient site with soft and pliable tissue, covering exposed nerves and tendons.
    MeSH term(s) Adolescent ; Female ; Femoral Artery/surgery ; Forearm/surgery ; Humans ; Mammaplasty/methods ; Perforator Flap/blood supply ; Reconstructive Surgical Procedures/methods ; Soft Tissue Injuries/etiology ; Soft Tissue Injuries/surgery ; Thigh/surgery
    Language English
    Publishing date 2022-07-25
    Publishing country United States
    Document type Case Reports ; Review
    ZDB-ID 605524-2
    ISSN 1098-2752 ; 0738-1085
    ISSN (online) 1098-2752
    ISSN 0738-1085
    DOI 10.1002/micr.30941
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Superficial outside-flap shunt (SOS) is associated with a low incidence of postoperative DIEP flap venous congestion: A single-institution retrospective cross-sectional study.

    Salzillo, Rosa / Boriani, Filippo / Atzeni, Matteo / Haywood, Richard M / Persichetti, Paolo / Figus, Andrea

    Journal of plastic, reconstructive & aesthetic surgery : JPRAS

    2023  Volume 85, Page(s) 367–375

    Abstract: Introduction: Venous congestion burdens up to 15% of deep inferior epigastric artery perforator (DIEP) flap breast reconstructions. For these cases, venous augmentation by superficial outside shunt (SOS) is associated with 100% success in secondary ... ...

    Abstract Introduction: Venous congestion burdens up to 15% of deep inferior epigastric artery perforator (DIEP) flap breast reconstructions. For these cases, venous augmentation by superficial outside shunt (SOS) is associated with 100% success in secondary salvage surgeries. Intraoperative venous augmentation using other techniques yields a 0.3% rate of return to theater due to venous congestion, but there is no evidence assessing the effectiveness of the SOS technique applied preventively. Comparing this preventive approach to data prior to its implementation, we expect to find a reduced number of venous congested flaps with reduced flap losses and revision surgeries.
    Patients and methods: This retrospective cross-sectional study involved DIEP flap breast reconstructions performed between 2011 and 2020. The control group included patients receiving additional venous anastomosis as a secondary salvage procedure. The "preventive SOS group" included patients who received preventive SOS during the main surgery. Age, body mass index (BMI), pregnancies, perioperative treatments (neoadjuvant or adjuvant chemo or radiotherapy), follow-up complications (arterial ischemia, venous congestion, hematomas, partial/total flap loss), and revision surgeries (breast debridement, flap remodeling) were recorded and compared.
    Results: Within 695 flaps performed, 397 flaps were included in the control group, and 298 flaps were included in the preventive SOS group. The groups were homogeneous for age (p = 0.418), BMI (p = 0.747), and flap weight (p = 0.064). Fifty-one flaps (12.8%) in the control group compared to zero (0.0%) in the preventive SOS group required return to theater (p < 0.001).
    Conclusions: We reported encouraging preliminary results for SOS to prevent DIEP flap venous congestion. These results must be validated prospectively.
    MeSH term(s) Humans ; Retrospective Studies ; Hyperemia/etiology ; Hyperemia/surgery ; Hyperemia/prevention & control ; Cross-Sectional Studies ; Incidence ; Mammaplasty/adverse effects ; Mammaplasty/methods ; Perforator Flap/blood supply ; Epigastric Arteries/surgery
    Language English
    Publishing date 2023-07-21
    Publishing country Netherlands
    Document type Journal Article
    ZDB-ID 2217750-4
    ISSN 1878-0539 ; 1748-6815 ; 0007-1226
    ISSN (online) 1878-0539
    ISSN 1748-6815 ; 0007-1226
    DOI 10.1016/j.bjps.2023.07.036
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: Breast reconstruction using the profunda artery perforator (PAP) flap: Technical refinements and evolution, outcomes, and patient satisfaction based on 116 consecutive flaps.

    Atzeni, Matteo / Salzillo, Rosa / Haywood, Richard / Persichetti, Paolo / Figus, Andrea

    Journal of plastic, reconstructive & aesthetic surgery : JPRAS

    2021  Volume 75, Issue 5, Page(s) 1617–1624

    Abstract: Introduction: When a deep inferior epigastric artery flap is not suitable, the profunda artery perforator (PAP) flap can be a good alternative for autologous breast reconstruction. Popularity of the PAP flap is expanding, but it is still only slowly ... ...

    Abstract Introduction: When a deep inferior epigastric artery flap is not suitable, the profunda artery perforator (PAP) flap can be a good alternative for autologous breast reconstruction. Popularity of the PAP flap is expanding, but it is still only slowly being adopted worldwide. We report our experience with 116 consecutive PAP flaps showing refinements and evolution of the technique towards improvement in outcomes and patients' satisfaction.
    Methods: We prospectively collected data from consecutive PAP flap breast reconstructions performed from 2016 to 2019. Patients' demographics, pre-, intra-, postoperative data, and revision procedures were analyzed. The BREAST-Q and a specific questionnaire investigating outcomes at the donor site were completed preoperatively and 12 months postoperatively.
    Results: One-hundred and sixteen PAP flaps were performed in 86 patients, 64 unilateral and 22 bilateral breast reconstructions. Mean body mass index was 24.72 kg/m
    Conclusions: Breast reconstruction with PAP flap yields a high success, low complications, and excellent cosmetic outcomes in the breast and donor sites. It improves patients' satisfaction and quality of life; hence, it can be considered an excellent option for autologous breast reconstruction.
    MeSH term(s) Arteries/surgery ; Breast Neoplasms/complications ; Breast Neoplasms/surgery ; Female ; Humans ; Mammaplasty/methods ; Patient Satisfaction ; Perforator Flap/blood supply ; Postoperative Complications/etiology ; Quality of Life ; Retrospective Studies
    Language English
    Publishing date 2021-12-01
    Publishing country Netherlands
    Document type Journal Article
    ZDB-ID 2217750-4
    ISSN 1878-0539 ; 1748-6815 ; 0007-1226
    ISSN (online) 1878-0539
    ISSN 1748-6815 ; 0007-1226
    DOI 10.1016/j.bjps.2021.11.085
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Unilateral immediate deep inferior epigastric artery perforator flap breast reconstruction following skin sparing mastectomy: A comparative study on revision surgeries to improve breast symmetry.

    Atzeni, Matteo / Salzillo, Rosa / Haywood, Richard M / Persichetti, Paolo / Ribuffo, Diego / Figus, Andrea

    Microsurgery

    2022  Volume 42, Issue 8, Page(s) 766–774

    Abstract: Background: The number of revision surgeries to improve breast asymmetry after deep inferior epigastric perforator (DIEP) flap breast reconstruction is still high worldwide with impact on both patients and healthcare systems. These procedures include ... ...

    Abstract Background: The number of revision surgeries to improve breast asymmetry after deep inferior epigastric perforator (DIEP) flap breast reconstruction is still high worldwide with impact on both patients and healthcare systems. These procedures include fat grafting, contralateral breast symmetrization, scar revision, flap repositioning and remodeling. A previously published DIEP flap insetting algorithm has proven to be effective in selecting patient-tailored strategies to achieve excellent aesthetic outcomes. This study investigated whether this insetting algorithm was effective in reducing revision surgeries in patients undergoing SSM and immediate DIEP flap breast reconstruction to achieve the goal of a one-stage reconstruction.
    Methods: This retrospective case-control study included 60 patients (group A) treated without the DIEP flap standardized insetting algorithm and 60 patients (group B) treated with the standardized insetting algorithm, which considers among its variables the type of breast to be reconstructed, abdominal tissue thickness, rotation due to harvesting side. Demographic data, operative data, complications and number of revision surgeries were recorded.
    Results: One hundred and twenty primary and 106 revision surgeries were performed. Groups were homogenous for age (p = .32), body mass index (p = .77), flap weight (p = .7), operative time (p = .87) and early complications (p = .78). When excluding isolated nipple reconstruction from the revision surgeries, one-stage reconstruction was successfully performed in 26 patients in group A (43.3%) and 39 patients (65.0%) in group B, with a statistically significant difference between the groups (p = .003).
    Conclusions: The introduction of a standardized insetting algorithm for immediate unilateral DIEP flap breast reconstruction can be effective in reducing the number of revision surgeries for breast asymmetry, making a one-stage reconstruction an achievable and reliable target.
    MeSH term(s) Humans ; Female ; Mastectomy/methods ; Perforator Flap/blood supply ; Epigastric Arteries/transplantation ; Retrospective Studies ; Case-Control Studies ; Reoperation ; Breast Neoplasms/surgery ; Mammaplasty/methods
    Language English
    Publishing date 2022-08-02
    Publishing country United States
    Document type Journal Article
    ZDB-ID 605524-2
    ISSN 1098-2752 ; 0738-1085
    ISSN (online) 1098-2752
    ISSN 0738-1085
    DOI 10.1002/micr.30945
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: Narrow inferior-central septum-based pedicle: A safe technique to improve aesthetic outcomes in breast reduction.

    Longo, Benedetto / D'Orsi, Gennaro / La Padula, Simone / Atzeni, Matteo / Vanni, Gianluca / Buonomo, Claudio Oreste / Cervelli, Valerio

    Journal of plastic, reconstructive & aesthetic surgery : JPRAS

    2023  Volume 85, Page(s) 226–234

    Abstract: Background: Inferior-central pedicle has some aesthetic drawbacks, including hypertrophic scar along the inframammary fold (IMF), squaring of the breast contours, and propensity to develop long-term 'bottoming-out.' This study aimed to verify if the ... ...

    Abstract Background: Inferior-central pedicle has some aesthetic drawbacks, including hypertrophic scar along the inframammary fold (IMF), squaring of the breast contours, and propensity to develop long-term 'bottoming-out.' This study aimed to verify if the narrow inferior-central (NIC) septum-based pedicle can allow the surgeon to improve aesthetic outcomes compared with the traditional inferior-central pedicle approach.
    Methods: Forty breasts underwent NIC-based breast reduction (group A), and 37 underwent traditional inferior-central pedicles (group B). The NIC pedicle was drawn with a width of 3.5-4.5 cm. The recorded measurements were sternal notch to nipple distance (S-N) and nipple to IMF distance (N-IMF) at the time of preoperative markings and follow-up 1, 6, and 18 months after the procedure.
    Results: The two groups were homogeneous regarding demographics, operative data, and preoperative S-N and N-IMF distances. Both groups showed no total or partial nipple-areola necrosis. At the 18-month follow-up, S-N (p < 0.00001) and N-IMF (p = 0.00039) distances were statistically different between the two groups, in favour of NIC group A. Changes in N-IMF distances between the 1- and 18-month visits were statistically different among groups (p < 0.0001), with a length variation of + 17.51% and + 28.46%, respectively. Patient satisfaction rate regarding "breast shape" (p = 0.021), "lower pole appearance" (p = 0.00017), and "scar" (p = 0.047) were higher in group A.
    Conclusion: NIC-based pedicle proved to be a safe procedure and allowed us to overcome limitations that typically characterise the inferior pedicle, i.e., 'bottoming-out' deformity, hypertrophic scar of the lower pole, and squaring of the breast contours.
    Level of evidence: II.
    MeSH term(s) Humans ; Cohort Studies ; Follow-Up Studies ; Cicatrix, Hypertrophic/surgery ; Treatment Outcome ; Retrospective Studies ; Surgical Flaps/surgery ; Hypertrophy/surgery ; Mammaplasty/methods ; Nipples/surgery ; Esthetics
    Language English
    Publishing date 2023-07-11
    Publishing country Netherlands
    Document type Journal Article
    ZDB-ID 2217750-4
    ISSN 1878-0539 ; 1748-6815 ; 0007-1226
    ISSN (online) 1878-0539
    ISSN 1748-6815 ; 0007-1226
    DOI 10.1016/j.bjps.2023.07.016
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article ; Online: The profunda artery perforators: Anatomical study and radiological findings using computed tomography angiography in patients undergoing PAP flap breast reconstruction.

    Sonda, Regina / Atzeni, Matteo / Martini, Federica / Kohlschëen, Eva / Monticelli, Andrea / Baruffaldi-Preis, Franz W / Saba, Luca / Bassetto, Franco / Tiengo, Cesare / Figus, Andrea

    Journal of plastic, reconstructive & aesthetic surgery : JPRAS

    2024  Volume 89, Page(s) 164–173

    Abstract: Background: The popularity of the profunda femoris artery perforator (PAP) flap is increasing; however, knowledge concerning the standardization of radiological findings and their clinical implications is limited. We evaluated the radiological ... ...

    Abstract Background: The popularity of the profunda femoris artery perforator (PAP) flap is increasing; however, knowledge concerning the standardization of radiological findings and their clinical implications is limited. We evaluated the radiological architecture of posterior thigh perforators using Computed Tomography Angiography (CTA) to identify landmarks to facilitate flap dissection.
    Methods: A retrospective study was conducted on 35 patients who underwent unilateral breast reconstruction with a PAP flap. The preoperative CTA scans were analyzed, and the perforator characteristics were evaluated. The perforators were mapped using a Cartesian coordinate system. Data were normalized by anatomical landmarks and overlapped. Perioperative and postoperative results were analyzed. Radiological and intraoperative were compared.
    Results: Two CTA scans were excluded; 66 thighs were examined. The mean perforator number was 3.2. The mean diameter of chosen perforators was 2.7 mm (DS ± 0.6 mm) at the origin, 2.2 mm (DS ± 0.4 mm) at the adductor space midpoint, and 1.7 mm (DS ± 0.3 mm) at the deep fascia. The mean adipose tissue thickness was 3.35 cm (DS ± 0.94) at the deep fascia and 3.59 cm (DS ± 1.19) at the adductor space midpoint. Intraoperatively, the perforator was located 3.22 cm (DS ± 0.87) from the posterior border of the gracilis muscle and 8.98 cm (DS ± 1.44) from the inferior gluteal crease. A radiological area located 9.33 cm (DS ± 4.81) from the y-axis and 7.48 cm (DS ± 1.88) from the x-axis was identified.
    Conclusions: CTA using the volume-rendering technique is a valuable method to study in vivo the radiological anatomy of the posterior thigh perforators.
    MeSH term(s) Humans ; Computed Tomography Angiography ; Retrospective Studies ; Perforator Flap/blood supply ; Mammaplasty/methods ; Femoral Artery/surgery ; Thigh/diagnostic imaging ; Thigh/surgery ; Thigh/blood supply
    Language English
    Publishing date 2024-01-09
    Publishing country Netherlands
    Document type Journal Article
    ZDB-ID 2217750-4
    ISSN 1878-0539 ; 1748-6815 ; 0007-1226
    ISSN (online) 1878-0539
    ISSN 1748-6815 ; 0007-1226
    DOI 10.1016/j.bjps.2023.12.006
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Book ; Online: Workers and Labour in a Globalised Capitalism

    Atzeni, Maurizio

    Contemporary Themes and Theoretical Issues

    (Management, Work and Organisations)

    2013  

    Series title Management, Work and Organisations
    Language English
    Size Online-Ressource (272 p)
    Publisher Palgrave Macmillan
    Publishing place Basingstoke
    Document type Book ; Online
    Note Description based upon print version of record
    ISBN 9780230303171 ; 023030317X
    Database Library catalogue of the German National Library of Science and Technology (TIB), Hannover

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  9. Book ; Online: Case-based Reasoning for Better Generalization in Textual Reinforcement Learning

    Atzeni, Mattia / Dhuliawala, Shehzaad / Murugesan, Keerthiram / Sachan, Mrinmaya

    2021  

    Abstract: Text-based games (TBG) have emerged as promising environments for driving research in grounded language understanding and studying problems like generalization and sample efficiency. Several deep reinforcement learning (RL) methods with varying ... ...

    Abstract Text-based games (TBG) have emerged as promising environments for driving research in grounded language understanding and studying problems like generalization and sample efficiency. Several deep reinforcement learning (RL) methods with varying architectures and learning schemes have been proposed for TBGs. However, these methods fail to generalize efficiently, especially under distributional shifts. In a departure from deep RL approaches, in this paper, we propose a general method inspired by case-based reasoning to train agents and generalize out of the training distribution. The case-based reasoner collects instances of positive experiences from the agent's interaction with the world in the past and later reuses the collected experiences to act efficiently. The method can be applied in conjunction with any existing on-policy neural agent in the literature for TBGs. Our experiments show that the proposed approach consistently improves existing methods, obtains good out-of-distribution generalization, and achieves new state-of-the-art results on widely used environments.

    Comment: Published as a conference paper at ICLR 2022
    Keywords Computer Science - Computation and Language ; Computer Science - Machine Learning
    Subject code 006
    Publishing date 2021-10-16
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  10. Book ; Online: SQALER

    Atzeni, Mattia / Bogojeska, Jasmina / Loukas, Andreas

    Scaling Question Answering by Decoupling Multi-Hop and Logical Reasoning

    2021  

    Abstract: State-of-the-art approaches to reasoning and question answering over knowledge graphs (KGs) usually scale with the number of edges and can only be applied effectively on small instance-dependent subgraphs. In this paper, we address this issue by showing ... ...

    Abstract State-of-the-art approaches to reasoning and question answering over knowledge graphs (KGs) usually scale with the number of edges and can only be applied effectively on small instance-dependent subgraphs. In this paper, we address this issue by showing that multi-hop and more complex logical reasoning can be accomplished separately without losing expressive power. Motivated by this insight, we propose an approach to multi-hop reasoning that scales linearly with the number of relation types in the graph, which is usually significantly smaller than the number of edges or nodes. This produces a set of candidate solutions that can be provably refined to recover the solution to the original problem. Our experiments on knowledge-based question answering show that our approach solves the multi-hop MetaQA dataset, achieves a new state-of-the-art on the more challenging WebQuestionsSP, is orders of magnitude more scalable than competitive approaches, and can achieve compositional generalization out of the training distribution.

    Comment: NeurIPS 2021
    Keywords Computer Science - Machine Learning ; Computer Science - Artificial Intelligence ; Computer Science - Computation and Language ; Computer Science - Information Retrieval
    Subject code 004
    Publishing date 2021-10-27
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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