Out-of-Distribution Optimality of Invariant Risk Minimization

Deep Neural Networks often inherit spurious correlations embedded in training data and hence may fail to generalize to unseen domains, which have different distributions from the domain to provide training data. M. Arjovsky et al. (2019) introduced the concept out-of-distribution (o.o.d.) risk, which is the maximum risk among all domains, and formulated the issue caused by spurious correlations as a minimization problem of the o.o.d. risk. Invariant Risk Minimization (IRM) is considered to be a promising approach to minimize the o.o.d. risk: IRM estimates a minimum of the o.o.d. risk by solving a bi-level optimization problem. While IRM has attracted considerable attention with empirical success, it comes with few theoretical guarantees. Especially, a solid theoretical guarantee that the bi-level optimization problem gives the minimum of the o.o.d. risk has not yet been established. Aiming at providing a theoretical justification for IRM, this paper rigorously proves that a solution to the bi-level optimization problem minimizes the o.o.d. risk under certain conditions. The result also provides sufficient conditions on distributions providing training data and on a dimension of feature space for the bi-leveled optimization problem to minimize the o.o.d. risk.Comment: 23 pages, submitted for a publicatio

Microinjection-Based RNA Interference Method in the Water Flea, Daphnia pulex and Daphnia magna

It is well known that most daphnid species have several attractive life history characteristics such as cyclical parthenogenesis, environmental sex determination, and predator-induced defense formation. Recent advances in high-throughput omics technologies make it easy to obtain a huge number of potential candidate factors involved in environmental stimuli-triggered phenotypic alterations. Furthermore, our group has developed a microinjection system to introduce foreign materials such as nucleotides and chemicals into the early-stage (one-cell stage) egg of Daphnia pulex and Daphnia magna. Consequently, we established a microinjection-based RNAi system that allows arbitrary gene functions to be investigated. However, this microinjection system does not seem to have pervaded in the daphnid research community due to its low throughput and high level of skills required. In this chapter, we review the microinjection method and its RNAi system in water fleas, D. pulex and D. magna, providing some technical tips and making challenging proposals for the development of novel high-throughput RNAi methods. Finally, we provide an overview of recently developed gene functional analysis methods such as overexpression and genome-editing systems

In-situ ice and meteorological observations in the southern Sea of Okhotsk in 2001 winter: ice structure, snow on ice, surface temperature, and optical environments

The 2001-ice season in the Sea of Okhotsk was characterized by extraordinarily developed ice extent. During the period February 17 to 21, we conducted in-situ observations in the southern ice area with the icebreaker \u27Soya\u27. In this paper, we show the observational results, concerning the core sampling of about 1.3 m-thick ice, snow sampling, surface temperature, and solar radiation under clear sky conditions. It is shown that (1) the sampled ice core is composed entirely of granular ice, (2) the 30 cm-thick snow pack overlying sea ice is composed mainly of depth hoar and significant vertical gradients of δ^O and temperature are found within the snow, probably associated with the depth hoar formation, (3) surface temperatures as low as about -30°C are detected on snow-covered sea ice floes at nighttime under almost clear and light breeze conditions, (4) from the estimation of the turbidity coefficient, the atmosphere over the ice-covered area is considered to be significantly clean. Furthermore, the NOAA/AVHRR satellite data are used to estimate the surface temperature distribution in the southern Sea of Okhotsk. It is shown that these data are useful for discriminating thick ice floes

チョウヘイソク オ キタシタ シキュウ ケイガン ショウチョウ テンイ ノ 1レイ

We report a patient of a metastatic small intestinal tumor from uterine cervical cancer. A 76 year-old woman admitted to our hospital because of dyspnea. She showed progressive acute renal failure with pulmonary edema. Abdominal CT showed an advanced uterine cervical tumor and bilateral hydronephrosis. She was treated with temporary hemodialysis and tube nephrostomy. 1 week after admission, she presented with severe nausea, vomiting and rapidly progressive abdominal distension. We diagnosed her as strangulated ileus of the small intestine and she underwent an emergency operation. Laparotomy revealed an isolated tumor of the ileum and dilatation of the proximal small intestine without peritoneal dissemination, and a partial resection of the ileum was performed. Histopathological findings showed that the tumor was composed of squamous cell carcinoma cells, indicating that it was metastasis from uterine cervical cancer. Metastatic small intestinal tumor from primary uterine cervical cancer is very rare. To our knowledge, only 5 cases have been reported in Japan, including the present case

イマチニブ ガ チョコウ シ チョウキ カンゼン カンカイ CR オ イジ シテ イル ショウチョウ GIST フクマク ハシュ サイハツ ノ 1レイ

We report the case of a patient with recurrent gastrointestinal stromal tumor （GIST） complicated with peritoneal dissemination who achieved long-term complete remission （CR） with imatinib mesylate therapy. A 64-year-old man was admitted to our hospital because of severe abdominal pain. Abdominal computed tomography （CT） showed free air and an intra-abdominal abscess. Perforation of the small intestine was diagnosed, and an emergency operation was performed. Two adjacent tumors （each,6cm in size）, one of which was ruptured, were found by laparotomy in the jejunum and as a peritoneal dissemination. Jejunojejunostomy with the two adjacent tumors was performed and as much of the disseminated tumors as possible were resected. Histopathological analysis indicated a high-risk GIST of the small intestine. Abdominal CT at 1.5 years after the initial operation showed multiple recurrent tumors due to peritoneal dissemination. The patient subsequently received imatinib mesylate therapy at 400mg/day, and 5 months later, abdominal CT showed no evidence of tumor recurrence. DNA analysis of the tumor revealed an exon 11 mutation in the c-kit gene. The patient continues to receive imatinib mesylate therapy （400mg/day）, and CR of the recurrent tumors has been maintained for 8 years and 7 months

Metabolomics reveals an involvement of pantothenate for male production responding to the short-day stimulus in the water flea, Daphnia pulex

Under favorable conditions, the micro-crustacean Daphnia pulex produces female offspring by parthenogenesis, whereas under unfavorable conditions, they produce male offspring to induce sexual reproduction (environmental sex determination: ESD). We recently established a suitable system for ESD studies using D. pulex WTN6 strain, in which the sex of the offspring can be regulated by alterations in day-length; long-day and short-day conditions can induce female and male offspring, respectively. Taking advantage of this system, we have already demonstrated that methyl farnesoate (MF) synthesis is necessary for male offspring production, and identified ionotropic glutamate receptors as an upstream regulator of MF signaling. Despite these findings, the molecular mechanisms associated with MF signaling have not yet been well elucidated. In this study, we analyzed the whole metabolic profiles of mother daphnids reared under long-day (female-producing) and short-day (male-producing) conditions, and discovered that pantothenate (vitamin B5), a known precursor to coenzyme A, was significantly accumulated in response to the short-day condition. To confirm the innate role of pantothenate in D. pulex, this metabolite was administered to mother daphnids resulting in a significantly increased proportion of male offspring producing mothers. This study provides novel insights of the metabolic mechanisms of the ESD system in D. pulex

トクシマシ ヤカン キュウジツ キュウビョウ シンリョウジョ ノ ゲンジョウ ト カダイ : ショウニ キュウキュウ タイセイ ノ キキ

Night and holiday emergency clinic of Tokushima City（Emergency clinic）was open １９９６ in Tokushima by entrusted Tokushima City Medical Association. Both pediatrics and internal medicine are under treatment as a first emergency clinic. Emergency clinic is open at every night through a year and at daytime on holiday. As Emergency clinic moved to Fureai Kenko-kan in ２０００, patients were convenient to visit and increased gradually in number. In２００５as a designated administrator, Tokushima Medical Association managed Emergency clinic independently. Especially swine influenza was extremely popular as pandemic in ２００９, and the number of patients was above １８０,００ as a new record. The patients were divided about７０％ of pediatrics and about３０％ of internal medicine, and from in and outside of Tokushima City. The main problem is the difficulty of acquisition because of the lack of pediatricians. As for the protection of the emergency system for children in Tokushima Prefecture, residents need enlightenment of decreasing unnecessary and nonurgent visits. So residents are encouraged to keep this emergency system by themselves. We hope emergency medical system for children in Tokushima will be established as soon as possible

Adaptability and selectivity of human peroxisome proliferator-activated receptor (PPAR) pan agonists revealed from crystal structures

The structures of the ligand-binding domains (LBDs) of human peroxisome proliferator-activated receptors (PPARα, PPARγ and PPARδ) in complexes with a pan agonist, an α/δ dual agonist and a PPARδ-specific agonist were determined. The results explain how each ligand is recognized by the PPAR LBDs at an atomic level